Biwiring - I Cant Choose a Cable!
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New member Username: Jazzy639Post Number: 1 Registered: Mar-06 | Hello, I've got a fairly cheap but decent hi fi from Richer Sounds, UK. Cambridge Audio A5 Amp, TDL KV1 Bookshelf Speaker. I currently use single wire Gale X315 cable - its copper and quite thick. I am wanting to Biwire and I have been reading What Hi FI. The choice seems to be between Chord Carnival Silver and QED Silver Anniversary. I am looking for nice crisp treble but then again, still lots of bass. On my current setup, the very high frequencies are clear but I am looking for the high frequencies to be a bit clearer than the moment as they are quite muddy. I have heard the QED has good treble but they can be a little too bright. I am looking at cable at under £10/metre. Any advice or suggestions would be greatly apprechiated! Thanks |
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Bronze Member Username: Mortal_oneCanada Post Number: 15 Registered: Nov-04 | Well I would say to do a test first. This will put you out a few pounds but not much and is a very good exercise. Go take the bars that are between the posts on the back of the speakers off and connect them using a couple of inches speaker wire. Listen for a week. Perhaps if you have couple of minutes go back and for between the two. Next go by yourself a very large power cord, must be 12 gauge! (SWG). I am not sure how the British would mark this on the extension cords, but you are looking for the almost industrial type, heavy, three conductors in fine. Over here on the other side of the water it would have a mark on it that says "12/3". Now cut that sucker in four, this is the hard part. Wire snips will be needed! Or a knife! Descard the ends, stupid molded plastic crap. Strip the ends down to the wire, if you do not have wire strippers, they are cheap and if you can use scissors, they are that easy. Wire up your speaker with the ugliest speaker wires ever! Listen for a week. Buy the way you will not be able to stop looking at them so close your eyes, turn out the lights, cover them up, do whatever you can. You can make them prettier later. Tell us what you think. Mention how everybody thinks you are crazy! I hope this makes sense. |
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New member Username: Jazzy639Post Number: 3 Registered: Mar-06 | Well, thanks for your suggestion but I really don't think power cable can match oxygen free speaker cable. Id rather go out and spend £33 GPB on QED Anniversary XT cable! |
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Bronze Member Username: Mortal_oneCanada Post Number: 16 Registered: Nov-04 | You are quite correct it is only a suggestion, and not an impractical one, and very easy to do with a little time invested. Any exercise that can help educate is never a loss. All I can say is check out. http://www.audioholics.com/techtips/audioprinciples/cables.htm Just a thought, and also fun. |
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New member Username: Jazzy639Post Number: 4 Registered: Mar-06 | Thanks |
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Bronze Member Username: Mortal_oneCanada Post Number: 17 Registered: Nov-04 | Oh and one more thing J. Replacing the bars on the back of the speakers between the binding post with actual speaker cable has always brought forward an improvement in sound when I have done this. Try it first. |
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New member Username: Jazzy639Post Number: 5 Registered: Mar-06 | Well I went ahead and ordered the more expensive QED XT300 cable so I wont be bi-wiring. I was looking at solid pure silver speaker jumpers but i think ill try some of the speaker cable first! Thanks for the tip |
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Silver Member Username: GmanMt. Pleasant, SC Post Number: 864 Registered: Dec-03 | Biwiring has no electrical effect if the speaker wire has lower series impedance than the source impedance of the power amp and the speaker- (both these conditions are commonly satisfied with any good 12-14 gauge wires, as long as the wire isn't too long for the application). One can't get any more power from 1 or 20 wires coming from an amp channel. Law of physics. With some very low ohm speakers and poorly designed speakers that have very low impedance dips then bi-wiring may be helpful by increasing the apparent diameter of the wire. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7869 Registered: May-04 | Pssst, Greg, bi-wiring isn't about how much power you get to the speaker. Where did you get that idea? Please explain how bi-wiring could make an improvement on; a) "poorly designed" speakers, 2) "speakers that have very low impedance dips". a) While some very poorly designed speakers might gain some benefit from bi-wiring, that would suggest bi-wiring would be useless on a well designed speaker. So how come all those expensive speakers have the capacity for bi-wiring? Do you really think the speaker designers are in league with the cable guys just to get us to spend more money? Do you think Oswald acted alone? Are you telling Jazzy his TDL's are poorly designed since they have provisions for bi-wiring? 2) Any speaker with a crossover will have some peaks and dips in its impedance curve. Is it only the speakers with very low impedance dips that would benefit from bi-wiring? Why would that be affected by additional wire? So how come all those speakers that don't have very low impedance dips have the capacity for bi-wiring? "Biwiring has no electrical effect ... " That's not true at all. Separating the ground paths for the various drivers has an obvious electrical "effect". "When two such filters (low pass for the woofer and high pass for mid+high) are combined and share a common resistance (speaker leads) back to the source (the amplifier), interaction is inevitable, with the resulting final frequency and phase variations being unpredictable in real life."* Greg, I guess I need to read some more. I've never seen any of your conditions or explanations for the benefits of bi-wiring from anyone I trust. Therefore, some links would be nice. * http://sound.westhost.com/bi-amp.htm |
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Silver Member Username: GmanMt. Pleasant, SC Post Number: 866 Registered: Dec-03 | Jan- My point is the following: The law of "superposition" (the basis for why a speaker can reproduce a complex series of wavelengths simultaneously) states that any two voltages applied to a linear network (in this case, a crossover) will have the same voltage transfer as if they were applied separately. Simply stated, it says that any two currents applied simultaneously to a linear network result in the same current as when applied individually. Getting to my point of poorly designed speakers: If the crossover is poorly isolated (bass to Mid/treble) no manner of cable TWEAKING will correct it. Increasing the apparent diameter through bi-wiring may help it, but it won't cure it. Regarding the bi-wiring adherents and some suppliers claim that running bass and treble frequencies protects the delicate trebles from the mean bass currents is sheer nonsense. If you are bi-wiring by connecting to the same amp channel there is no benefit, unless you are using very long speaker runs with very thin wire. Just get 12-14 gauge wire and you will be good to go. Since most speakers are designed with passive crossovers, bi-wiring ends up being a waste of money--but it is very beneficial to the dealer and manufacturer. The simple explanation for why the advantages of bi-wiring are pretty much nonexistent is that most people only have speakers built for bi-wiring, while their amplification is not. By using the same amplifier channel for both sets of bi-wire cables (both sets are connected to the same binding posts on the amplifier or receiver), the same electrical path is being used for both sets of terminals on each speaker, thus negating any advantages of bi-wiring. All the power has to go through the passive crossover anyway, whether with standard, bi, or tri-wiring. From an electrical perspective (and that is the only perspective the drivers care about), this is NO different than running one speaker cable to the speaker, and bridging the two sets of terminals together with the bar or plate. If you notice, most bi-wireable speakers have plates, rods, or wires connecting the speaker connections anyway. This should tip you off on the BS of bi-wiring. The speaker manufacturers do this because they need the power to pass through the passive crossover for the drivers to operate properly. By using the same amplifier channel (and terminals) for each set of bi-wire terminals on your speakers, you would be bridging the two sets of terminals together with your amplifier (since they share the same connection point on the amplifier). The only advantage in most setups (only speakers built for bi-wiring) for bi-wiring would be using twice as much physical wire (two separate runs to each speaker, thus making the wire act as if it is thicker. However, if you are already using a fairly low gauge speaker cable, such as 10-14 gauge there is nothing to be gained by "doubling-up" unless you have 100 foot runs at 4 ohms-or 200 foot runs at 8 ohms, which is certainly a rarity, unless your home theatre is the size of an auditorium. The added expense of running twice as much speaker cable for a an inaudible difference doesn't make too much sense. Bi-wiring only makes sense when it is used in conjunction with bi-amping (running more than one amplifier channel per speaker). In order to bi-amp correctly, an external active crossover between the preamplifier and each amplifier channel will be needed (so that only the high-frequency or the low-frequency parts of the signal will be amplified), and the internal crossovers inside the speakers will need to be disconnected (so that each amplifier will go directly to the corresponding speaker driver, i.e. the woofer for low frequency and the tweeter for high-frequency). I personally don't know of many people who will go to these extremes to take advantage of the benefits of bi-wiring, so bi-wiring just ends up getting WAY more attention than it should. And if the speaker is designed to operate properly in passive crossover, why mess with it. Bi and tri-wiring makes good sense when you have a speaker system designed around active crossovers. These are often the best speakers and are ideal for DIY-ers. Go to the Siegfried Linkwitz site (famous for the Linkwitz-Riley crossover)for some great active crossover designs. |
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Bronze Member Username: DobyblueSt. Catharines, Ontario Canada Post Number: 53 Registered: Oct-05 | I wish I had read that before I spent so much money on my Ultralink Excelsior 2.4 cables. Amp end 2 ports to speaker end 4 ports. Speakers roughly a 10 foot fun from the amp. Am I stil using a good cable? Picture of speaker end :- |
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New member Username: Jazzy639Post Number: 6 Registered: Mar-06 | Well, My Cambridge Audio A5 Amp has two outputs for the left speaker and two for the right, presumably for bi-wiring. Would that be classed as a different output so I would be effectively utilising bi-wiring? Thanks |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7880 Registered: May-04 | J Azzy - Classed as a different output? No, about the only thing Greg has correct would be the two speaker posts for each channel act as "A" and "B" speakers (without the A/B switch I assume) and are wired in parallel to the same output devices internally in the amplifier. But how your amplifier is connected internally is not the issue on which bi-wiring's benefits hang. Greg, I guess if you start off with the wrong supposition for what bi-wiring will do, you will come to the wrong conclusion regarding its benefits. (However, it is interesting to know you believe Oswald was part of a conspiracy.) You seem to be under the impression bi-wiring is all about adding more wire guage to the connection between amplifier and speakers. I have no idea where you got that idea (I'd appreciate if you'd show me) since you haven't provided any links or even any of your infamous quotes to your posts; but I have never, until now, heard anyone explain bi-wiring in terms of guage of cable. Bi-wiring is about separating the electrical ground paths in the crossover. It is primarily concerned with the voltage that comes out of the woofer's motor (back EMF), not what is going into the crossover from the amplifier. If you understand that your law "says that any two currents applied simultaneously to a linear network result in the same current as when applied individually", you should understand that any current or voltage coming from the woofer as a result of the voice coil's movement will not have the ability to stop, look both ways and decide it will only go back to the amplifier where it will be met by some circuitry or a transformer to keep it from doing further damage. If the woofer and other drivers share a common signal/ground path in the crossover, the energy from the woofer's motor will end up on a path that leads to/from the other drivers. By physically breaking that path at the crossover, bi-wiring acts as a traffic cop to direct the large motor's energy away from any path(s) which would cause it to swamp the smaller signals leading to the higher frequency drivers just as it would swamp the outputs of the amplifier if it weren't handled properly. Your logic here seems a bit tortured and distorted, Greg. If we ignore the idea that bi-wiring is about the conspiracy to buy more cable to make "larger" cable, we can first address the idea that all the energy has to pass through the passive crossover, and that the way the amplifier is wired internally has any effect on the performance of the speaker. There can be little argument that most amplifiers have all their speaker outputs connected in parallel. But, that has nothing to do with bi-wiring other than as a convenience feature. By separating the ground paths for the vaious drivers we are breaking the simplest, straightest, possibly lowest resistance path for the energy from the woofer to disturb the voltage meant for the tweeter. So, in this case, all the energy created in the function of an amplifier driving a speaker is not going through the whole crossover; it is passing only through the portions of the Xo it needs to do its job of driving the speaker. "From an electrical perspective (and that is the only perspective the drivers care about), this is NO different than running one speaker cable to the speaker, and bridging the two sets of terminals together with the bar or plate." I hope you see that your sentence is incorrect in that you are assuming the connection at the speaker end is the same as the connection at the amplifier end. Where the ground path is terminated is the difference here. If you isolate the ground path to a termination point at the amplifier, it isn't likely to find its way back to the high frequency drivers. "If you notice, most bi-wireable speakers have plates, rods, or wires connecting the speaker connections anyway. This should tip you off on the BS of bi-wiring. The speaker manufacturers do this because they need the power to pass through the passive crossover for the drivers to operate properly." Now, Greg, I assume when you typed that, you knew it was gibberish and really rather blatantly false. "Bi-wiring only makes sense when it is used in conjunction with bi-amping (running more than one amplifier channel per speaker)." This makes no sense either, Greg. Either bi-wiring has some advantage by your logic or it doesn't. But your logic falls apart once your begin to describe "bi-amping". You should know that many speakers designed for bi-wiring also. Bi-amping is allowed because the electrical path between the drivers is disconnected when the jumpers are removed. There is no need to disconnect the internal passive filters. If you send a signal from one amplifier to the woofer and it is met by a low pass filter which limits the information going to the woofer to, let's say, beneath 2kHz, the speaker will only see the signal beneath 2kHz from that amplifier. The highs will still be filtered off so why would you "have to" disconnect the filter itself? That you might prefer an external active crossover is one reason, but that is not what you stated. Likewise, with the second amplifier in a bi-amped system, feeding the signal through the speaker's internal high pass filter network will keep the low frequencies from destroying the tweeter. And, there, when there are no common signal paths between the two amplifier and the drivers they are attached to, you have a bi-amped system using the internal Xo. It is not considered a bi-wired system at that point because it is a bi-amped system instead. A point you seem to prefer to obscure, Greg. So, with your mistake there out of the way, we still haven't got an explanation for why you believe bi-wiring will work well in a bi-amped system but not in a single wire system. And, I think this is where, other than the guage thing you're hung up on, we can see how your understanding of what bi-wiring is attempting to achieve is faulty. You really confuse the two words and methods as if you didn't know any better. Possibly you just haven't given bi-wiring enough attention. You made no attempt to dissaude me from thinking you totally made up the stuff about "some very low ohm speakers and poorly designed speakers that have very low impedance dips". You know there are more than enough "well designed" speakers which have quite fanatical impedance curves. You should also know that impedance alone does not make a speaker easy or difficult to drive. But, I guess there's no sense in explaining that "dippy" idea when your whole concept of just adding "more cable" is the hingepin of your argument against a very logical process. Finally, the suggestion to visit Prof. Linkwitz's web page for some Xo designs was gratuitous and I am actually insulted that you thought I'd fall for that, Greg. There are more than enough speaker designers who feel bi-wiring has minimal effects on performance, all or most of which can be equalled or bettered by buying one good cable. How these designers build their Xo's isn't the issue here. I am not promoting bi-wiring just because Oswald didn't act alone. There is no conspiracy between manufacturers, Greg. There are some positive benefits to be had with bi-wiring a properly designed speaker. Too many companies use bi-wiring capability as a marketing tool and not as a way to tweak a bit more performance from their designs. That is not my point. My point is, you have this whole bi-wiring thing wrong, Gregory, and you seem to want to use gobbledegook words and incorrect ideas to cover your mistake. If you seriously think bi-wiring is only about adding more "apparent" (?) guage to the connection, please, provide me with a location where you found that idea. It is as wrong as several of the other concepts you've posted on this thread. |
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Bronze Member Username: Mortal_oneCanada Post Number: 18 Registered: Nov-04 | Now Jan. It was a nice normal conversation between un-enlightened fools before you had to step. There are popular misconceptions between bi-wiring speakers. "Why does everybody put those !@#$%^&* things back there anyways?" And most people do confuse bi-amping and bi-wiring. No they are not related at all. A quick search for diagrams will clearly show that. And anybody who was done it will tell you about the pinch in the pocket book. Now I do have questions for you. When bi-wiring and connecting the two runs back from the binding posts at the speakers (connectors removed) to the amp. You still have the connection at the binding posts at the amp. When you attach the two runs, do you think that because they are bound at the same place that current would actually flow to the other cable threw the same points of connection? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7883 Registered: May-04 | Sorry, TMO, I'm not clear what you're asking. If you are suggesting two conductors connected at a common location can create a "continuous" signal path, then, in most cases, I would agree. However, you haven't asked whether that connection is always "perfect" due to the effects of resistance, capacitance or inductance. My understanding is any such connection can range from a near zero Ohms impedance to an open circuit. However, I can't agree that bi-wiring and bi-amping are not related at all. They are clearly related in that either technique depends on breaking a common connection point between the various drivers and the amplifier. Bi-amping totally does away with the common connection of all drivers to a common amplifier's outputs. Bi-wiring does away with the common connection within the speaker's crossover and places that location at the lower impedance point of the amplifier. In a very broad sense, you can think of bi-wiring a crossover as similar to star grounding an amplifier. Let me ask you a question or three. If you have a motor which produces voltage and current, what will the motor do with that energy product? It must go somewhere; correct? The motor assembly of the speaker's voice coil produces energy as the voice coil moves within a magnetic field. Where does that energy go? What does it do when it gets there? If you have a motor outputting alternating current through a wire, what happens when that common wire is split in two directions? Does energy stop to consider that taking one path is better than going toward the other path? What would keep it from taking one path or the other from a common connection point? Is there a difference between a connection made at the amplifier's outputs (which should act as a zero impedance source) vs. a connection to the amplifier's outputs which is shared by all the drivers, inductors, capacitors, resistors and cable within a speaker/crosssover? What if there were no crossover, just a common connection point and two cables? What is intermodulation distortion? Feel free to go back to my linked article (http://sound.westhost.com/bi-amp.htm#fig5) or any other treatise on biwiring you can find. Here are a few to choose from; http://search.yahoo.com/bin/search?p=biwiring%20speakers I recommend staying away from those selections which are merely forum discussions. You know how inaccurate most forum discussions tend to be. |
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Bronze Member Username: Mortal_oneCanada Post Number: 19 Registered: Nov-04 | Now you are talking! I think we should go back to the plumbing analogy. Water will take the path of least resistance, now will the current do the same? Or will apply itself evenly across both? If both being equal then both would receive (given two) half. And from what I understand, and that is very little, a connection is just that. A point at which two things meet. The difference between a connection at an amp and that at the loudspeaker is very different, if you are bi-wiring. You are splitting the signal in two (given two equal wires, length and all variables being the same) and then connecting them to two separate inputs and that is very different than taking one set of wires and applying the current to two points. I guess my questions was, if you connect the two sets of wires at one point (the amp) will this connection be affecting the final result of the current? |
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Bronze Member Username: Frostyda9Calgary, AB Canada Post Number: 95 Registered: May-05 | What if one were to design and build a diode array that would positively prevent the LF driver's back EMF from interefering with the HF driver's path back to the amplifier? You could then reap the benefits of a biwire setup, while using only one standard wire to the speaker. Thoughts? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7887 Registered: May-04 | "The final result of the current"? I guess what you mean is; will the needs of each driver and its appropriate filter network react the same or differently when you connect the cables at different points in the speaker/amplifier circuit? I would surmise that at the beginning of the night the current requirements of both/all sections of the speaker will be essentially the same whether there is one wire or two (or three) feeding the signal to the speaker's crossover. The woofer will usually draw the most current and the components within the low pass filter will typically present the largest problems to the amplifier. However, as the night wears on and the inductors, caps resistors and voice coils have heated up from the energy passing through them, the current requirements of the driver will change somewhat as will the overall character of the filter network. The midrange and tweeter, however, will have a different degree of change compared to the woofer. The inductors, caps and resistors feeding the high pass side of the system will typically be smaller in value and will respond diffferently to the heat induced changes. By feeding these two networks separately, the amplifier should be in better control of the speaker's requirements. Placing the amplifier's common connection point within the crossover is less likely to provide the same results. This shouldn't be taken to mean bi-wiring will only be beneficial after a few hours of listening. This is just trying to answer the question regarding "the final result of the current". |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7888 Registered: May-04 | I assume the diodes might help somewhat in defeating crosstalk between drivers, but they wouldn't address some of the other problems of a single wire crossover design. There would be no change in the alteration of current requirements as the components change value with heat and there would certainly be no benefits to the mutual inductance of the circuit when passing large amounts of current. The addition of even the simplest diode configuration would add to the complexity of the crossover design while adding what would probably amount to very little benefit to the speaker manufacturer. There are more than enough speaker designers who feel a well designed Xo can deal successfully with the problems which bi-wiring seems to address. There are more than enough speakers which have bi-wiring facilites that provide little benefit other than to the marketing department. My choice would be a design meant to deal with the problems bi-wiring has pointed up while maintaining the simplicity of the straightest path from amplifier to driver. The over abundance of speakers which present difficult loads to an amplifier is further proof, in my estimation, that speaker and amplifier designers are seldom on the same page. Simplify the loads and make the entire system of amplifier and speaker more efficient in its operation and I would bet many of today's problems and hypothetical "solutions" would disappear. |
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Silver Member Username: GmanMt. Pleasant, SC Post Number: 868 Registered: Dec-03 | Jan- In a passive crossover speaker where the electrical information to operate the speaker goes through the crossover to operate properly, please explain what bi-wiring accomplishes? Unless you disable the croosover (which would probably ruin the speaker) the information is going through the crossover anyway, regardless whether you bi-wire or not. It is similar to splitting a 10" diameter pipe into 2 x 5" diameters pipes and then putting them back together into a 10" pipe. What is accomplished? Bi-amping in an active crossover system definitely makles sense. But then you aren't using the same amp channels for each crossover circuit. |
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Silver Member Username: GmanMt. Pleasant, SC Post Number: 869 Registered: Dec-03 | Fort bi-wiring to have any effect in a passive crossover system, one would have to have at least a 3 driver system with at least 2 crossovers that can be electrically separated. If the speaker is capable of that, then there may be a small difference. But any more dramatic difference would require a different amp channel. In a 2-driver passive crossover system there would be no real difference. |
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Silver Member Username: GmanMt. Pleasant, SC Post Number: 870 Registered: Dec-03 | Jan- I'm not a conspiracy theorist. You should stop attributing your nonsensical presumptions about others that you know next to nothing about. Oddly, many flame-ups on this forum have centered around you. I wonder why? You should learn to make your comments about audio without adding ad hominem attacks. |
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Bronze Member Username: Mortal_oneCanada Post Number: 20 Registered: Nov-04 | Gregory, Jan has probably forgot more than you can remember. And it may seem that he is stating fact, and he is, he is also stating opinion also, and he has a great way to pick out the stupid things we say (type). As to bi-wiring. If you presume that the two sets of inputs (binding posts) on the back of the are cabinets actually doing something. Then the idea is that the crossover is actually separated into a high and low frequency section at those inputs (posts). The idea is that the bars that go across the two inputs allow the current to flow to the two halves. There are actually two separate input therefore into the crossover itself. So bi-wiring does make sense because they are electrically separated. Two-way or three-way does not matter. Except if you are in bed with some fine ladies, then it counts! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7893 Registered: May-04 | Gregory - As to your post on Wednesday, March 15, 2006 - 12:12 pm; what part of the explanations I have provided in my last five posts are you failing to comprehend? If the explanations provided in those posts don't begin to at least make you consider you have been provided the information you need in reply to, "please explain what bi-wiring accomplishes", you are clearly just not going to accept any explanation that doesn't concur with your already decided upon position of, "I can't hear it, it doesn't measure any different and therefore can't be" world. It does measure diferently if you take the voltage and current from a low impedance source and return it to a low impedance source rather than distributing it through a higher impedance location. Please go back and read what I've posted and ask a specific question that I might be able to answer instead of asking me to repeat everything I've said. And keep an open mind this time, Greg. Regarding your post from Wednesday, March 15, 2006 - 12:27 pm; I see no logic, and you've provided no logic, for this statement. My argument has been stated as to the why's of bi-wiring's benefits. Your argument at this point is nothing more than a point of contention which indicates your shifting stance on bi-wiring and your inability to adjust to the logic of the argument. Please make a correction here, Greg, or provide some reasoning for what you stated against what you have already put on this thread. Finally, as to your post from Wednesday, March 15, 2006 - 12:34 pm; your final statement is all that needs to be said. You cannot make an argument regarding being "attacked" without adding your own personal salvo. You are a conspiracy nut! You have adopted the opinion that audio companies are out to manipulate the consumer and most things audio are a sham. You see things that aren't there and can't hear things which are. As to why so many new comers seem to want to pick me off; I've wondered that myself. Surely suggesting to ERC that he should lay off the caffiene was in no way an insult nor required the response it received. But, like so many before him, he decided it was wise to pick off the big dog with the Gold status. Testosterone driven madness? Maybe. All I know is many who have taken me on are no longer on the forum and I am. Seems the administrator doesn't see my faults which you find so obvious. Gregory, you and I disagree about most everything audio. I have nothing against your personally. But what you post is sometimes nothing more than drivel. Such as, "If you notice, most bi-wireable speakers have plates, rods, or wires connecting the speaker connections anyway. This should tip you off on the BS of bi-wiring. The speaker manufacturers do this because they need the power to pass through the passive crossover for the drivers to operate properly." What does that say, Greg? Nothing! That's what it says. Your idea about adding more "apparent" wire to the connection is clearly incorrect and, as I've said, can only be the ravings of a conspiracy nut. I disagree with you, Greg. Take that as my position on letting something I see as blatantly incorrect stand. If you put something in print and I disagree, I'll let you know. You can promote whatever gear you like on the forum as long as when you do, everyone knows you don't think equipment sounds different and you pick your own stuff based on the warranty and the remote. That really seems fair to me. |
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Silver Member Username: EldTexas Post Number: 118 Registered: Dec-05 | Hehehe, I'm glad my wife doesn't look at this forum, TMO. <IMG SRC="https://www.ecoustics.com/bbs/clipart/happy.gif" ALT=":-)" BORDER=0> I didn't want to get drag into this technical thread. <IMG SRC="https://www.ecoustics.com/bbs/clipart/sad.gif" ALT=":-(" BORDER=0> This is a classic case where everyone is correct, just from different viewpoints. Law of Superposition and Law of Relativity. Bi-wiring is not always better, it could make your speakers sound worst, too many factors. That is why Dynaudio likes to control it with one crossover and one set of wires, could the Dyn speakers sound better with Bi-wire, definitely! Could it sound worst, with me tinkering with it, yes! <IMG SRC="https://www.ecoustics.com/bbs/clipart/happy.gif" ALT=":-)" BORDER=0> Like TMO said, one can have two separate crossovers with two drivers. Check out these DIY crossover on the ProAc Reponse 2.5 |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7895 Registered: May-04 | Eld - I can't imagine why or how bi-wiring would harm a speaker's performance. (With the possible exception of someone who tries to DIY a single wire crossover into a bi-wired coinfiguration.) The idea of bi-wiring is merely to treat each driver, or group of drivers, as a separate low source impedance signal path to and from the amplifier. There is no technical reason I am aware of which indicates a speaker should have the signal path of all drivers combined on one crossover board. In fact, from what I understand of bi-wiring it should only be a benefit to the speaker's performance to have each driver handled separately. How much improvement is made with bi-wiring can be debated, but the logic behind bi-wiring seems solid to me. As I said, think of bi-wiiring as a form of star grounding and I think you'll see the obvious benefits. It might not be deemed an improvement in terms of what any one person perceives to be beneficial against the cost of the additional cables, particularly if you are not attuned to the benefits which bi-wiring can bring to a speaker's sound. And that sometimes minimal improvement is the case with many speakers which have jumped on the bi-wire bandwagon for marketing purposes. Unlike bi-amping, bi-wiring is not a proven path to improvement with any and all speakers. But I can only see the extra cable as a benign addition to the connection. In this case, Gregory's idea of additional guage of cable would be a benefit assuming the user didn't begin with 8AWG and the amplifier can deliver the amount of current a lower guage cable can deliver. |
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Silver Member Username: EldTexas Post Number: 119 Registered: Dec-05 | Jan, Generally, I see bi-wiring will reduce bass response while improving the high response, since the worst feedback from the driver will be in the Low line. If your bass is already bad and treble is ok, you might not want to do bi-wiring, this will only inrease the low and hi discrepency. Also, it can affect the "bass" integration into the system by slowing the bass line while improving the treble line. The gap in the crossover can be more pronounce if not design correctly. Also opens the possibilities of user error, using the wrong gauge line for Hi and Low. Like you said, this all assumes we can hear the difference. Very nice to have bi or tri-wire option though.  |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7898 Registered: May-04 | OK, once again I don't see how bi-wiring can reduce bass response. Nor, can I see anything which would "slow" the bass line or affect bass integration. If anything, the point of bi-wiring should be to lower the source impedance of the electrical circuit between the amplifier and the driver and therefore better facilitate current delivery to the woofer. My guess would be that should make the low frequencies "better". Properly implemented, bi-wiring should only separate the signal path for the low frequency network and driver from the rest of the crossover and higher frequency driver(s) in the speaker. The amplifier's connection to the woofer is still made through the same low pass crossover components. It is usually the inductors and caps in the filters which give bass a "slow" sound by altering the electrical phase angle. Otherwise the sound of the driver is not changed and, if it was a good choice before bi-wiring, it's integration with the rest of the system shouldn't change by the process of bi-wiring. Please explain how you see this degradation of quality happening? What is it about bi-wiring that you believe would adversely affect the low frequency response? |
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Silver Member Username: EldTexas Post Number: 120 Registered: Dec-05 | I think you explained it earlier, Jan: "Bi-wiring is about separating the electrical ground paths in the crossover. It is primarily concerned with the voltage that comes out of the woofer's motor (back EMF), not what is going into the crossover from the amplifier. If you understand that your law "says that any two currents applied simultaneously to a linear network result in the same current as when applied individually", you should understand that any current or voltage coming from the woofer as a result of the voice coil's movement will not have the ability to stop, look both ways and decide it will only go back to the amplifier where it will be met by some circuitry or a transformer to keep it from doing further damage. If the woofer and other drivers share a common signal/ground path in the crossover, the energy from the woofer's motor will end up on a path that leads to/from the other drivers. By physically breaking that path at the crossover, bi-wiring acts as a traffic cop to direct the large motor's energy away from any path(s) which would cause it to swamp the smaller signals leading to the higher frequency drivers just as it would swamp the outputs of the amplifier if it weren't handled properly." |
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Silver Member Username: KanoBC Canada Post Number: 881 Registered: Oct-04 | Bottem line please, you guys lose me with all the technical. If I wanted to lose the jumper on my towers, would it be better to use - 1) Two wires from the amp to the towers 2) One wire which splits into 2 at the speaker 3) One wire from amp to speaker, with an extra cable connecting the binding posts. |
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New member Username: SerniterPiscataway, New Jersey USA Post Number: 2 Registered: Mar-06 | As I understand it, its choice 1) The one thing that I wonder is if the 'back EMF' can interfere with signals at the amplifier terminal itself, from where two distinct wires are run to the speaker terminals. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1607 Registered: Dec-04 | The back emf, or CEMF(counter electro-motive force) is delivered right back to the amplifier, generated motly by the heavy coil of the woofer, generating it's own current via the moving coil in a fixed magnetic field. Without this 'feedback', the amp would be running in open loop with no reference, or disallowed the 'global fedback' which is useful in a lot of ways. The amp uses the CEMF as a reference. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1608 Registered: Dec-04 | By the way, electricity is not a water tower as a capacitor, a resistor is not a skinny pipe and amperage is not a resevoir or water where people fish while it is not being used. Ohm's Law Or something like that, as I recall, it usually works. But I never studied law... |
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Bronze Member Username: Frostyda9Calgary, AB Canada Post Number: 99 Registered: May-05 | That is the million dollar question in my mind, Srinivas. What also makes the question interesting to me is that no matter what configuration you decide to use, ultimately there will be continuity between the return paths of the cables. Be it at the speaker (strips) in the wire (2 to 4 cable) or at the amplifier itself (internal cotacts that parallel the outputs). Biwiring is like religion, everyone has an opinion, yet no one can seem to definitively prove anything... |
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Silver Member Username: Timn8terSeattle, WA USA Post Number: 826 Registered: Dec-03 | Damping factor. "Unlike bi-amping, bi-wiring is not a proven path to improvement with any and all speakers." I believe this to be a true statement. Try it, if you don't like it or it doesn't change anything it's completely reversible. |
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Silver Member Username: EldTexas Post Number: 121 Registered: Dec-05 | I'm out of my league. How many circuit system are we talking about? One or two? Based on Superposition, is the overall voltage drop in the system the same with single or bi-wire arrangement? Is the net impedance in the wires equal in single or bi-wire (interesting)? What does relativity have to do with each mini-loops until you hit the amp binding post? Is your current or voltage the same at the binding posts no matter if its one set or two or three sets of wires coming from the speakers? Interesting questions...I knew I shouldn't have started in this thread so I will exit. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7899 Registered: May-04 | Let's try this again and hope the computer doesn't eat this reply. How many cables? Four. Two, dual conductor cable runs. Some manufacturers are placing four leads inside one dielectric (outer insulation). Eld - My post which you quoted says nothing about reducing the voltage or current to the woofer. There are other factors which affect the quality of bass response but in this thread we are only interested in bi-wiring and therefore the other factors (the amplifier's performance) haven't changed. If you care to explain what you are seeing that I'm not posting, feel free. Yes, the back EMF has to be dealt with somwehow, somewhere. EMF is a function of the movement of the driver's voice coil within a fixed magnetic field and therefore can be controlled to some extent by the mechanics of the speaker itself. The combination of a floppy driver suspension and an amplifier that allows the driver to "ring" will have the most problems with EMF. What you should know, if you take nothing else away from this discussion, is back EMF is dealt with by the amplifier's "damping factor". To begin, the speaker's mechanics will determine just how much EMF voltage is generated by the driver's voice coil. Large coil, more EMF. Longer travel within the magnetic gap, more EMF. More current in due to impedance, more EMF out. And so forth. Then that voltage has to make its way back to the amplifier along the ground path of the same crossover and cables which were used to make the driver move in the first place. Since speakers are ultimately inefficient devices and energy is lost in significant amounts within the crossover's components, the EMF is dissipated as it passes through the crossover and speaker cable and turned into heat just as the incoming energy has been. As the EMF voltage arrives at the amplifier our discussion turns to which type of output device does it meet there. In a tube amplifier, the EMF will (typically) face an output transformer which effectively isolates the output devices from the speaker. However, tube amps present a unique problem to dealing with EMF since they generally have a high output impedance and therefore low damping factor, i.e., more speaker "ringing". We all remember what more speaker movement gets us; don't we? In a solid state amplifier the output impedance is much lower and the EMF can be dealt with in several ways. The various protection devices which are found on amplifiers, notably "current limiting" will deal with EMF in one fashion. A Zobel network placed at the outputs will deal with the problem in another way. Current dumping amplifiers have their own little quirks when it comes to EMF. Protection devices and Zobels have fallen out of favor with the audiophile circuit readers due to their effects on sound quality. Current dumping amplifiers tend to blow up speakers when they see a shorted circuit which is what too much EMF amounts to. In the high end market one approach to EMF has been to design amplifiers with such high current capability that the amp becomes a champion rodeo bull standing amidst a field of mewing kittens. Most solid state amplifiers incorporate the EMF into the negative feedback network, as Nuck has suggested. However, the reliance upon NFB to deal with EMF has caused many a cheap amplifier problems. Obviously the more EMF you add to the NFB the more likely it will be that a difficult speaker will ultimately end up driving the amplifier (into oscillation). The cheap amplifier's solution to this is to place protection devices at the outputs. You can see how this becomes a vicious circle. The many problems and solutions which EMF presents are beyond the space allowances of this thread and my ability to present them in a simple manner. Here are a few links you can research should you want to know more. http://sound.westhost.com/project33.htm http://www.symphonysound.com/articles/tubefriendly.html From the above linked article: "What is Back EMF? Back EMF is one variable which is difficult to gauge from impedance graphs but contributes significantly to how tube-friendly a given speaker will be. Consider for a moment how a loudspeaker operates: an amplifier excites a loudspeaker driver by sending it current. Now look at the process in reverse: if you excite a loudspeaker driver (by pushing on it gently, for example) you will send some current from the speaker to the amplifier. You have simply reversed the circuit. Back EMF may be thought of in this context. Thus we know that when the amplifier is sending current to the speaker, and the speaker's driver's are moving, current is coming back from the speakers to the amplifier. Mathematically the amplifier sees this current as negative current because it flows in the opposite direction of the current it is sending to the speaker. The simplest way to think of Back EMF is to associate it with a net reduction in the loudspeaker's impedance. Back EMF is most severe with poorly damped woofers. As a result, if a speaker sends large amounts of Back EMF back to the amplifier, it will typically do so when reproducing lower frequencies, for those frequencies are where larger drivers reach their peak of excursion. Thus it is common to find speakers which perform well on tubes except for when music with a lot of bass information is played, at which point the speaker falters and the sound degrades quickly. This is simple the result of the bass frequencies exciting a large, "floppy" driver which in turn generates Back EMF and lowers the impedance. Hence some trial and error is in order. Simply glancing at an impedance graph will not always guarantee that a speaker is a good match. An impedance graph does not show the effects of Back EMF because Back EMF varies considerably based on the source material used. At the risk of repeating ourselves, much as one cannot simply judge the quality of a speaker by staring at its impedance graph, one cannot pass judgement on the sound of a speaker based on how much Back EMF it generates. All of the variables we have discussed in this article simply relate to how tube-friendly a given speaker will be, and hence how good it will sound when driven by tubes. A speaker with a low impedance, high capacitance, and significant Back EMF may sound fabulous on the right amplifier. But an important consideration when optimizing the sound of that speaker would be choosing an amplifier which can adequately handle the demands placed upon it by such electrical characteristics. Solid State Can be Picky Too! Let's discuss solid state amplifiers for a moment. It is important to understand that our entire discussion of impedance and Back EMF applies to all amplifiers, not just tube amps. Not all solid state amps are well suited to a speaker whose impedance dips below 4 ohms Some amplifiers make use of circuitry which is referred to as "current limiting" which simply means that as a speaker presents a lower and lower impedance to the amplifier, the amp actually decreases current output. For many amplifiers, current output is limited into loads lower than 4 ohms. What this means, essentially, is that a speaker whose impedance dips below 4 ohms for substantial portions of the audible spectrum will not be driven to its full potential by a current limiting solid state amp. This is why in our discussion of sensitivity we stated that a high sensitivity does not guarantee that a speaker will play loudly, even when driven by a solid state amplifier. Given a speaker with extremely low impedance, on the wrong solid state amp, you will hit a ceiling past which you simply cannot play regardless of sensitivity. Which amplifiers are current limiting? That is a question your dealer should be able to answer, and if not the amplifier's manufacturer certainly can. The reason that so many cheap receivers and amplifiers are unable to generate deep bass is that they have current limiting circuitry which prevents them from sending low frequencies at low impedance. Hence when connected to speakers with low impedance, particularly in the lower frequencies, these receivers or amplifiers will sound thin in the bass regions. Current limiting is not necessarily a bad sign: many wonderful solid state amplifiers make use of current limiting circuitry. Selecting speakers that will sound best on a current limiting solid state amplifier is a similar process to selecting speakers for a tube amplifier, although one need not be quite so rigid in one's criteria. Typically solid state amplifiers, even those which are current limiting, are more immune to high capacitance than tube amplifiers, and large swings in impedance are less important so long as the minimum impedance remains above a reasonable value such as 4 ohms. Back EMF tends not to be a concern with solid state amplifiers unless the speaker has a low impedance and sends substantial amounts of Back EMF to the amplifier. For those speakers which present more difficult loads with extremely low impedance, solid state amplifiers which use "current dumping" circuitry should be chosen. Current dumping amplifiers continue to output more and more current until the impedance is vanishingly low. Typically such amplifiers will only shut down when a short is presented, or when they reach thermal instability." http://www.crownaudio.com/pdf/amps/damping_factor.pdf#search='loudspeaker%20emf' http://search.yahoo.com/bin/search?p=loudspeaker%20emf While not specifically dealing with the EMF affecting the other drivers (I believe the first linked article touches on this subject), these artciles should give you some further ideas about the why's of choosing to bi-wire a speaker's crossover network. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7900 Registered: May-04 | "How many circuit system are we talking about? One or two?" Bi-wiring would allow two semi-independent circuits originating at one location. Bi-amping creates two distinct, independent circuits originating from two locations. "Based on Superposition, is the overall voltage drop in the system the same with single or bi-wire arrangement?' I can't answer that. It would depend on the particulars of the circuits and where you measure from. "Is the net impedance in the wires equal in single or bi-wire (interesting)?" Depends on what "wires" you use. "What does relativity have to do with each mini-loops until you hit the amp binding post?" It means you've grown much older reading this thread unless you did it while orbitting the Earth. "Is your current or voltage the same at the binding posts no matter if its one set or two or three sets of wires coming from the speakers?" Which binding posts? At the amplifier, it should be, that is your (near) zero Ohms source impedance. At the crossover, no, it probably isn't. "Interesting questions...I knew I shouldn't have started in this thread so I will exit." Toodles! " ... ultimately there will be continuity between the return paths of the cables." Continuity, yes. There is continuity all the way back to your source player. But that does not imply similar signal paths. Electrically, the speaker doesn't care what CD player you use. |
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Silver Member Username: EldTexas Post Number: 122 Registered: Dec-05 | Jan, Thanks for the class on back flow EMF. We were looking at two different things, again, as you can see from my questions above. My point of view was the current flow between the mini loops for the parallel drivers and how they are changed relative to each other and your statement regarding the EMF affecting the crossover of the smaller drivers. Since the share points were moved from the crossover to the amp binding posts, the chance of the bigger EMF affecting the smaller driver is minimize, thus the smaller drivers are functioning more effciently, leaving less current to drive the bigger driver. At least this is what I thought your point was by moving the share points at the crossover to the binding posts of the amp. I didn't realize you were talking about the damping factor across the amp. Wouldn't this be the same, since all three driver network meets prior to crossing the amp, and the voltage drop would be the same either single or bi-wire between the binding postive and negative binding posts, like your answer above confirmed? I would guess voltage drop and dampening factor are not interlock. Thanks for answering my questions above. |
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Silver Member Username: EldTexas Post Number: 123 Registered: Dec-05 | Jan, Can you explain the two "semi" independent circuits orginating from the same source in Bi-wire? I always thought electrical loops are dependent of each other if sharing the same source, either in parallel or series. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7903 Registered: May-04 | I can explain "semi" as a convenience item I used hoping not to have to explain anything further. The circuits cannot be totally independent of each other with a common connection at the amplifier and no regulation stages beyond the output devices. But the amount of current migrating from the low pass section to the high pass section has been altered. You've created two circuits which feed from the same power source. They are not independent of each other but one is less influenced by the other than would be the case in a single wire set up. " ... thus the smaller drivers are functioning more effciently, leaving less current to drive the bigger driver." I'm not seeing how there would be less current coming from the amplifier to drive the low frequency system. I've never seen an explanation of bi-wiring which indicates any change in current availability from the amplifier by separating the networks, with the possible exception of the connection point having a slightly lower source impedance. That, however, should provide slightly better current flow on demand. Slightly is the operative word there and could vary to some degree if we consider Gregory's "poorly designed" speaker as the worst case. In most "well designed" speakers, I would suspect the change in available power would be noticeable to an astute listener, but not significant. Probably about what you would get from cleaning the pins on your output tubes or the RCA connections on your system. I suppose how the bi-wired crossover board is laid out could make some difference in whether the amplifier faces an difficulty once the speaker is biwired, but that would take a very poor designer who didn't understand at all how to arrange inductors and signal paths. Will damping factor remain the same? Sure, why not! "Damping factor" is a nebulus number which isn't much of a spec in the first place. It is measured (guessed at?) under static conditions much like RMS wattage and has no bearing on the real world conditions of an amplifier driving a real speaker and vice versa. The first time I ever had to deal with an explanation of damping factor was when Bob Carver put a 1000:1 damping factor on his Phase Linear amplifiers. The Macs and Citations were just stating 50:1 and no one cared to ask about damping factor. Of course the PL's usually burst into flames at the very sight of an electrostatic speaker while the Macs and Citations did yoe-man's work into a highly capacitive load. For the most part damping factor is a useless spec since it is a dynamic system. How the amplifier designer chooses to deal with the problem is going to make a large difference in what numbers they choose to present. Many tube amplifiers will take their feedback loop from the 16 Ohm tap and measure damping factor from there. That's terrific if you own a pair of LS3/5a's (as the "Tube Friendly Speaker" article points out). If you drive a nominal four Ohm load, that damping factor number has no meaning to you. My suggestion for anyone concerned about damping factor was to listen to something like the last movement of "The Firebird Suite" and as the drums whacked away, the strings strained and the horns got hornier, try to determine what the damping factor was for each drum strike. "That's about a 47.5." "That one's gotta be a 75." And so on. That game's best done with some single malt Scotch to bring clarity to the proceedings. If you are measuring the voltage drop across the amplifier's outputs, I would guess there might be another slight change when the system is bi-wired. I say that simply because the aim of separating the networks is to increase the efficiency of the system as a whole. But I don't know how you would measure that conclusively since you want a measurement that reflects the dynamic nature of the amplifier playing music. Does it really do any good to bi-wire a load resistor? This is where the "specs tell me all I need to know" people get upset with bi-wiring. Yes/no answers don't exist here. The system is dynamic and that seems to be largely ignored by the test bench crowd when the numbers won't fit their conclusions. One amplifier might do well when bi-wired to this speaker but not that speaker. One speaker might do well when bi-wired to one amp but not another. So, for anyone who wants audio to be a series of numbers which add up to a yes/no answer, bi-wiring's "suck it and see" approach is dismissed out of hand. The fact that cables enter into the equation makes bi-wiring bad joo-joo for any Luddite anyway. Perhaps Tim has more information regarding voltage drop since he, out of necessity, spends more time measuring things. That is the best answer I can provide. |
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Silver Member Username: EldTexas Post Number: 124 Registered: Dec-05 | Jan, Based on your answers, I think we are in agreement on these issues from the start. I thought we were miscommunication, and your answers confirmed we were thinking about the same thing. From my first post, the Law of Superposition would dictate the voltage difference in the total system remain the same across the amp (if there is any difference it would be very small), the Law of Relativity would dictates if the listener would perceive the difference in the Hi and Low loops when the crossing points are changed. Better or worst would depend on the relative impedance change in each loop and the listener preferences. "The fact that cables enter into the equation makes bi-wiring bad joo-joo for any Luddite anyway," can't agreed with you more. Cheers. |
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Bronze Member Username: Frostyda9Calgary, AB Canada Post Number: 100 Registered: May-05 | Has anyone mentioned the possibility of eddy currents circulating on the jumper bars? It would seem that the very short distance between the terminals when jumpered would be conducive to this effect... |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7915 Registered: May-04 | Nope, nobody's mentioned it. Most everybody just agrees it's best to ditch the stock jumpers. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1638 Registered: Dec-04 | Right hand rule in the North and Left hand rule in Australia et.al.? Using the clockwise/anti-clockwise flush test? The bars are of enough robustness to generate a current, yes. Is this RFI of any consequence? No. |
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Silver Member Username: Frostyda9Calgary, AB Canada Post Number: 101 Registered: May-05 | Here's one to think about...if you were to run two separate runs of cable from the amp to the speaker, while leaving the jumpers in place, would the net effect be the same as if you had used a single wire and the jumper bars? |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1639 Registered: Dec-04 | The bars are in place to signal the amp that the arrangement is single run, single speaker config.(unit power out) Pulling the jumper is a signal, and nothing else, that the amp is in multi-task or pre-amp operaton, usually meaning an external amp is being used. The big fat jumper is only cosmetic/ or easier to handle. |
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Silver Member Username: Frostyda9Calgary, AB Canada Post Number: 102 Registered: May-05 | Nuck, I am referring to the jumpers on the speaker terminals. The effect of biwiring whilst keeping the jumpers in place on the binding posts... |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1648 Registered: Dec-04 | Well, heck, just pull them bad boys outta there!Replace with speaker wire tout suite! |
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Silver Member Username: Frostyda9Calgary, AB Canada Post Number: 103 Registered: May-05 | hehe no worries Nuck, I am currently using two cables per speaker in my biwire setup. As for what I said, it was a somewhat logical progression to the conclusion that if you could isolate the high and low input from each other in one signal path direction only, you would have a system that behaved exactly as a biwire setup, yet only needed one wire to operate. Now I just need to see if I can build a prototype and prove my theory.. ;o) |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1650 Registered: Dec-04 | A very good thread all around. As I try to absorb a few of Jan's links I am reminded why I come here. Thanks folks. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1651 Registered: Dec-04 | The 'dumping' amp, BTW is denying the global feedback that most regular amps use as a 'mellowing' factor. An amp which might be described as 'warm' is influanced mostly by global feedback. A 'dumping' amp will be most accurate and revealing of any defiencies that exist. I like the description of dumping amps as 'stringent'. However, all SS amps use feedback to some extent. The lead or tail FET of a chain usage is usually the deciding factor in how the CEMF is used. A leading FET which bleeds the CEMF to the collector will be more infuenced than a design allowing tail FET's to bleed to the emitter. In either case, if ANY voltage is leaked to base, you get a $30 POS. And I didn't say Bose, did I? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7917 Registered: May-04 | "An amp which might be described as 'warm' is influanced mostly by global feedback." LUCEEE!!! YOU GOTTA LOTTA 'SPLANIN TO DO! |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1654 Registered: Dec-04 | Heck, I better bone up for this one. |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 1021 Registered: May-05 | Wouldn't a "warm amp" be best characterized as having a bump in the 125 Hz or so region? |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1667 Registered: Dec-04 | Sure, but where does Sarah McGlochlan sing? The push at 125 is a frontal and friendly nudge, but the front at 600 is where a 'warm' unit becomes'forward', but that is the sweet spot for a lot of female vocals. How can one unit, or kit, cover them all adequatly? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7923 Registered: May-04 | "Wouldn't a "warm amp" be best characterized as having a bump in the 125 Hz or so region?" Not by any definition of "warmth" that I've ever seen. According to Mr. Holt, who put most of these words in our venacular; "warm The same as dark, but less tilted. A certain amount of warmth is a normal part of musical sound." Hmmm, thanks, Mr. H. OK, then "dark" is; "dark A warm, mellow, excessively rich quality in reproduced sound. The audible effect of a frequency response which is clockwise-tilted across the entire range, so that output diminishes with increasing frequency. Compare "light." OK, last one, Gord. "light Lean and tipped-up. The audible effect of a frequency response which is tilted counterclockwise. Compare "dark." See, now what's 125Hz got to do with that? What a small blip/hump/rise at around 110Hz is called is the bottom half of a classic BBC curve. It is meant to give the impression of deeper bass than the speaker can actually produce by playing up the value of the second harmonic of those notes which fall below the speaker system's low frequency resonant point. But, it has nothing to do with a speaker being "warm". It might be found in speakers which are typically "warm". But that doesn't make the blip in the mid bass the cause of warmth any more than the cigarette lighter in your car makes it a pryotechnic device. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1688 Registered: Dec-04 | Yes it does. That bump in the mid-bass is what defines a speaker as warm, that is the description of the sound. It is designed in there for a reason, and that is to sound 'warm'. It works. We could argue over sounds with words on a page until our little fingers look like sausages, but the designers want a 'warm' sound, and achieve that by working about the 110-130 Hz bandwidth. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1689 Registered: Dec-04 | mmmm...sausages... |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7927 Registered: May-04 | I sincerely have to disagree. That would mean a speaker with a rising high frequency region, but with a bump at 125Hz, would be "warm". Nope, can't agree with that. Now, back to warm being influenced by global feedback ... |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7930 Registered: May-04 | I guess, since we're playing this game, someone might want to inform us how a designer would put a small frequency "bump" at 125Hz into a "warm amp". My concept of a BBC curve relates only to speakers and is fairly easy to accomplish by the designer. However, we were discussing "warm amps", so we might need a bit more 'splanin. Anyone have any ideas how this would be accomplished? |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1697 Registered: Dec-04 | Sure. Program the amp to use the PWM of the output stages to clip the upper and lower ranges of output between, say, 100 and 200 Hz. By shortening the pulse widths, the upper and lower stages are softened, thus the warm delivery in whatever frequency is chosen. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7938 Registered: May-04 | "Program"? |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1698 Registered: Dec-04 | Design, pardon me. Program, for new processors, like Outlaw, which I been looking at for days. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1699 Registered: Dec-04 | should read 'have been' |
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Bronze Member Username: Mortal_oneCanada Post Number: 21 Registered: Nov-04 | OK Jan you are starting to lose me. But from my limited knowledge I will try to understand. First question, global feedback network versus the negative feedback network? I know that you can change the way a negative feedback network works to reflect the class of amp you are designing. Will this have an effect on the sound? What is the difference between the two? I have heard also the diodes that are used can also effect the sound of a amp, given who long they store the current for, release times and efficiency. Somne starting ideas. I think I my have to go and revue some 1950's RCA schematics. |
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Silver Member Username: Frostyda9Calgary, AB Canada Post Number: 104 Registered: May-05 | TMO - diodes don't store energy, that is the realm of capacitors. Diodes function to allow current flow in one direction while suppressing it in the other, generally. I have a feeling you knew that, but somehow got your terms mixed up. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1702 Registered: Dec-04 | Yup, TMO meant caps, I bet. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1703 Registered: Dec-04 | And the caps'bleed off' power at the start or end of a mosfet chain, to either the emitter or collector, and create a 'warm' sounding power, these power downs can be directed to any frequency, the 100-200 is in question here. Warm. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7940 Registered: May-04 | Well, of course, I should have known you would just "design" the amp to have that hump. "Programming" is for DSP, not analog. So, how then do you "design" the amp to have this small rise in response centered around 110-125Hz? "First question, global feedback network versus the negative feedback network?" Feedback is feedback. You are taking a portion of the signal, measured in dB, and "feeding it back" to the input signal where it represents a negative waveform (see the text above). This negative waveform is either the negative current flow from the driver's EMF or the signal is phase inverted within the circuit. The feedback circuit "compares" the two signals by running them together, out of phase, and whatever emerges is the difference signal and represents the distortion of the input signal. The remainder is the signal minus the distortion and is considered the "cleanest" signal the amplifier/circuit can produce - hopefully - and is passed to the speaker terminals or the output of the circuit. http://search.yahoo.com/search?p=negative+feedback+audio+amplifier&sp=1&fr2=sp-t op&ei=UTF-8&SpellState=n-603743504_q-Eb0nYS6Ojf4b%2F%2FFksRp.DgABAA%40%40 You can have a local feedback network within a small portion of the amplifier's circuitry or you can have global feedback taken from the outputs back to the inputs. Or, you can have a bit of both. The amount of feedback is going to determine how stable the amplifier will be under load conditions. Most all amplifiers and particularly solid state designs will need some measure of feedback to remain stable. A bit of feedback will lower distortion. The more feedback you introduce to the amplifier, especially global feedback, the lower the distortion product will be, theoretically. In most cases while THD will decrease, IM and most especially TIM will increase expotentially. Slew rate will also suffer as NFB is increased. The amplifier will eventually become unstable and current will stop flowing in response to the speaker's requirements. At this point the amplifier changes it characteristics and attempts to dump enough voltage into the loudspeaker to make up for the lowered amperage. It will eventually feed upon itself to attain the needed voltage. In the end, the amplifier may go into oscillation which will enter the loop feedback and, if not stopped, destroy the amplifier. Feedback has become a bad word for some audiophiles who have learned about it only from their experience with cheap receivers. Some feedback is helpful while excessive feedback is often used as a poor substitute for good design. I have to stop for the moment. I'll be back to get to the other issues. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1704 Registered: Dec-04 | So the amplifier, given the opportunity and the proper NFB, will become a self-eating watermelon. I will bone-up, Jan and look forward to your leisure time. Thanks. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7941 Registered: May-04 | "feedback" The longest word in the English language that uses all the letters "A" through "F." Amazing what you can find on the internet! "And the caps'bleed off' power at the start or end of a mosfet chain, to either the emitter or collector, and create a 'warm' sounding power, these power downs can be directed to any frequency, the 100-200 is in question here." Nuck - I don't know that I understand what you're implying here. Are you proposing a circuit design which intentionally alters (power downs) the frequency response of an amplifier through all but a small region of the mid bass in order to make the 110Hz response stand out? And then brings the response back down to flat around 70-80Hz? If so, I have three questions. How many amplifiers have you seen measured that had this lump in their response? Have you seen any amplifiers which measure flat but are described as "warm"? And, aren't you now talking about a vastly more complex signal path which is anathema to good circuit design in high end audio? I can only see the addition of a sufficient number and size of capacitors to do this type of up/down frequency shaping adding far more phase problems than the effort would be worth. "I know that you can change the way a negative feedback network works to reflect the class of amp you are designing. Will this have an effect on the sound? What is the difference between the two?" Uh, two what? Feedback networks? That would be the answer I provided above; global feedback and local feedback. There is also feedforward but I don't know of anyone using that design idea at the present time. (But who knows. Nelson Pass loves that kind of quirky stuff.) The class of operation doesn't really dictate the way the designer would go about feedback. Most high end amplifiers and most cheap receivers run as class AB and yet the way they implement NFB is vastly different. As a rule class A amplifiers run small amounts of local feedback loops and disdain global feedback due to its perceived negative effects on sound quality and stability. Class AB amplifiers are all over the board with how NFB is utilized. Local feedback is typically kept to low levels and global FB is usually not in a high end designer's handbook. Different designers have various approaches however since a few db of global feedback can help in some cases. As the price lowers, the designers are often designing for specifications and global feedback becomes more prominent as the way to lower on paper THD specs. As I stated above this tends to make the amplifier unstable into low impedance and/or difficult to drive speaker loads or when high capacitance cables are used. Other forms of signal distortion creep into the picture as NFB is increased but receiver designers will sometimes seem to design for the THD spec a buyer will look at for comparison. Altering the amount of feedback in the amplifier will alter its gain also, so this is a desirable feature of high feedback amplifiers when designing for a specs are everything buyer. More gain in a circuit should make it less prone to noise but at the same time will make the amp even more unstable. Only one of those qualities appears on the spec sheet. The high end approach would normally be to use less gain acquired through feedback and better quality parts and circuit design/layout to lower the inherent noise floor. One of the improvements in high end audio that has occurred over the last thrity years has been the overall rise in quality of passive component parts such as caps, resistors and inductors. This has allowed designers willing to spend the money to purchase capacitors with a 1% tolerance where an amplifier such as my Mcintosh tube amps from the early 1960's had 5% caps and was considered as good as could be had in those days. Most of the lower priced amplifiers from the same time period, such as a Dynaco, used 10% tolerance on caps. My Macs had stock 1% to %5 resistors when it was designed. Today's top flight resistors are measured to within 0.1% tolerance. This tighter control over the specifications and tolerance for deviation from that spec in circuit design has improved the overall sound of the high end components of today. The materials used to construct the passive parts has changed drastically also. Polypropolene caps didn't exist until fairly recently in audio history. Now the swing is back to "better sounding" old fashioned but tightly toleranced paper in oil caps. All this has lead to the idea that all parts of the amplifier down to the input/output connectors will affect the sound quality. On this subject I will allow everyone to make their own decisons regarding what is important and what is still just a connector, or switch, or circuit board material, etc. Capacitors do affect the sound quality of an amplifier depending on where in the circuit they are used and for what function. Changing out the capacitors in my amplifiers made more improvement than any other type of component change I later made including the output tubes. Even the tech who felt "parts is parts" had to agree to that. Diodes in the power supply or in the output section of an amplifier can also affect the sound adversely. So, yes, you've heard correctly I would say. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7948 Registered: May-04 | Overall, this is a pretty good article covering the basics of negative feedback. Wade through the technical stuff to at least find some interesting ideas. http://www.normankoren.com/Audio/FeedbackFidelity2.html |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1709 Registered: Dec-04 | Wow, that's a lot of long-haired stuff. Me read. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7949 Registered: May-04 | Oongoywa, Simba, oongoywa! |
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Bronze Member Username: Armyscout42DUGWAY , UTAH USA Post Number: 47 Registered: Sep-04 | must everything be a CONSPIRACY? there is no conspiracy in regards to bi-wiring. it is absurd to stereo type and put all manufacturers, engineers and designers in the same boat. that is very close minded and rather absurd. there is a very common reason as to why speaker designers develop high end loudspeakers to be made to be bi wired or bi amped. after all, to say that german, swedish, danish, italian, british, american, canadian, japanese, chinese and others who manufacture high end loudspeakers are all in the conspiracy to get people to buy expensive cables is about as absurd as the world being flat. that's a paranoia or a delusion conjured up in one's mind. Not everything is made the same or designed the same. to say that bi wiring is a conspiracy is about as absurd as the bose crowd defending the bose as the best speaker in the world in which there is NONE! it's prefencial as bi wiring is to those who want to go another notch of CRITICAL listening for those in the high end world. Like speaker selection, so is bi wiring, bi amping and tweaks for all i care! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7952 Registered: May-04 | https://hometheaterhifi.com/volume_5_4/essaynegativefeedbackoctober98.html |
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Silver Member Username: PraetorianCanada Post Number: 118 Registered: Dec-05 | EC, not everyone who creates bi-wire/bi-amp ready speakers has to be taking part in a concerted effort to part us with our money, but this does not mean they are not complicit either. I certainly can see the merits of bi-amping in some applications, but bi-wire? In my opinion, the benefits are doubtful, but by all means your speakers = your set-up. However, to expand on my point: Whether or not manufacturers believe in any tangible benefits, the customers obviously do, and market pressures will force these company's to meet that particular demand, hence they make bi-wire ready speakers. |
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Bronze Member Username: Armyscout42DUGWAY , UTAH USA Post Number: 49 Registered: Sep-04 | Most high end manufacturers design for bi-wiring for technical reasons not because of consumer demands. you cannot mix general consumer electronics in the same level and manufacturing approach as the high end world. The high end community generally cater to those with large pocket books who are audiophiles not regular consumer based who are critical listeners or audiophiles. companies like acoustat, nikko audio, SAE, soundcraftsmen and the like could no longer compete as great as they were because of strict competition and the economy. Infinity and polk used to make real high end til they found it more conducive to tap into the general markets of home theater for general consumers which is much more profitable so they discontinued their high end division. some of your points maybe true regarding companies manufacturing bi-wire speakers just suit the consumer, but that is not the intention or the design approach of high end manufacturers. high end is not or never was intended for everybody as much lambhorgini and ferrari is not for everybody. Bi wire, bi amping, the use of power conditioners and filters are all there for a technical purpose in the high end world as much as sound processors, compressors, equalizers are to the recording/dj professionals. bi wire like all these items are merely an OPTION and the not the rule. sound processors are not the rule and that's my specialty. I wouldn't have a system without sound processors. to me no matter how expensive and high grade a system is, without my processors, it sounds just plain to me and not suitable for my needs. bi wire like SPECIFICATIONS is not really audible or recognizable to the common listener whether you believe it or not, such enhancements or optional set ups are designed and made for those that are critical listeners in the world of audiophiles. Many engineers, designers or inventors come up with products or devices out of their passion for the industry or there wouldn't be any progression in technological advancement. You cannot undermine those with innovative ideas who develop things out of passion not necessarily for profit. If that was the case then everybody would copy the bose approach of overpricing their products to 800% more than what it costs them to develop good or bad! Of course there are products more guilty than bose in overpricing, but this is not the bash the bose forum. In the high end world, you have $90k clearaudio turntables, the same price as a martin logan flagship statement e loudspeaker and you have 300lb each krell monoblocks costing $150k, you can buy a nice house for that in utah, arkansas, oklahoma or anywhere in the south. sure there are $8K speaker wires, there are also $10k phono cartridge too, there's a reason for it by the designers. sure for us average low paying workers, it's only worth $500 bucks on the most, so does elvis's lotus with a bullet in the car seat but worth millions to a collector! in my experience and personal taste, bi wire, bi amping and using higher cables does make a difference but not like night and day as what sound processors do that creates psycho acoustics like my bbe, carver holography, acoustic research, srslabs or peavey kosmos. I like some of the experience and more technical professionals here indicate things in the forum based on experience and technical knowledge not on sales. I'm not a salesman and neither are those who are sharing their technical expertise. Not everyone will ever meet eye to eye on anything. I hardly bi-wire myself but I do bi-wire on some of my loudspeakers and I do hear a slight difference because of it's design. I'm not an expert on the subject but merely defending it based on my experience and technical knowledge of my own systems designed for bi wiring. enough of bi wiring cause the subject is like any other subject, there will be pros and cons! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7968 Registered: May-04 | Are we still working on the "warm" amp theory? |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 1040 Registered: May-05 | Jan - Elvis has left the building |
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Bronze Member Username: DobyblueSt. Catharines, Ontario Canada Post Number: 55 Registered: Oct-05 | Infinity Series V Reference speakers were $70,000/pair back in 1990! Gorgeous creatures. http://www.6moons.com/industryfeatures/forbidden/billhero1.jpg http://www.6moons.com/industryfeatures/forbidden/forbidden_9.html |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1735 Registered: Dec-04 | Thank-you, thank-you verry much. See you in Memphis in May. |
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