Pwr Ratings Exposed
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Bronze Member Username: BlazerPost Number: 89 Registered: Feb-04 | I came accross this information on another website thread and found it extremely interesting. Enjoy! One of the biggest exaggerations in audio is surround receiver specifications. Most everyone claims at least 75W/ch or more, but most receivers put out about 1/3rd to half their rated power when all channels are running. So how can they claim that kind of power? FTC rules allow you to exaggerate power as long as you don't lie. As long as the receiver can put out 75W into any one or more channels under *some* condition, it is permissable to say "75W/ch". However, if you say "75W/ch RMS, all channels driven with .1% distortion" THEN you must be able to do this much power under these conditions. Unfortunately, most receivers aren't rated this way. IOW, most receivers are rated using a "best case scenario" instead of a worst case scenario. So, how does your receiver stack up? Well, we don't have all figures for all receivers, but we do have them from Home Theater magazine for the following units, all channels driven with .1% distortion (I can't verify that this is continuous power or peak power). Finally, HT has tested NAD's receiver. And now for some others (bold indicates the rated power is honest): NAD T753 Claimed - 70Wx6 Actual - 78Wx6, 94Wx5, 108Wx2 Kenwood VR-7070 Claimed - 120Wx6 Actual - 63Wx6 Pioneer VSX-D912K Claimed - 110Wx7 Actual - 41Wx7 Yamaha RX-V640 Claimed - 90Wx6 Actual - 39Wx6 Onkyo TX-SR601 Claimed - 85Wx6 Actual - 57Wx6 Denon AVR-2803 Claimed - 90Wx7 Actual - 25Wx7 H/K AVR-325 Claimed - 50Wx7 Actual - 53Wx7 Yamaha RX-V2400 Claimed -120Wx7 Actual - 32Wx7 Sunfire Ultimate Claimed - 200Wx7 Actual - 95Wx7 Kenwood Sovereign VR-5700 Claimed - 120Wx7 Actual - 77Wx7 Onkyo Integra DTR-9.1 Claimed - 130Wx7 Actual - 90Wx7 Rotel RSX-1065 Claimed - 100Wx5 Actual - 107Wx5 Linn Classik Claimed - 75Wx5 Actual - 43Wx2 Calculated - 17Wx5 |
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Bronze Member Username: MofoknowsPost Number: 46 Registered: Mar-06 | FTC enforcement in this area has always been a joke. Good for the industry. Not so good for the consumer. I guess that's why it's the Federal Trade Commission. |
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Silver Member Username: GeekboyTampa, FL United States Post Number: 436 Registered: Dec-03 | So, only the following do better (or as good as) advertised! Rotel Harman Kardon NAD Figures. This confirms our list. We've been tracking the Sound & Vision reports for some time now. Most of the details of the reports (bench tests) are available at http://audio.erobinson.net. I guess this is just more reinforcement. |
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Silver Member Username: HawkHighlands Ranch, CO USA Post Number: 740 Registered: Dec-03 | Blazer: I have been on this soapbox for the past 4 years, absolutely aghast at the crap that is foisted on consumers. Kudos to you for finding this info and publishing it here! It is no wonder that Mark Fleischman of Secrets of Home Theater recently wrote that he can count on one hand the companies that publish honest power ratings (while praising the Outlaw 1070 as an honest receiver). Just to provide further proof, I remember the Sound & Vision report of the Onkyo TX-SR901 about a year back. Onkyo claimed that their $1600 receiver was capable of 125W x 7, but actual bench tests showed the sucker clipped at a mere 56W when 5 channels were driven. |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 1065 Registered: May-05 | I've seen these before, but it's been a while since I've seen a current one. The biggest surprises for me were from Sunfire and Linn. I figured that these two (esp Linn) didn't need to fool around with numbers to make them look better. |
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Silver Member Username: ChitownPost Number: 908 Registered: Apr-05 | Some of these at the erobinson.net look a bit suspicious. How does the Marantz SR7200 claim 105wpc and produce only 29 and the lower sr5400 claim 90wpc and produce 103? They couldn't push the power from a lower unit into the higher one?? |
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Silver Member Username: GeekboyTampa, FL United States Post Number: 442 Registered: Dec-03 | Stof: you'll have to refer to Sound and Vision magazine for specifics. They run very specific bench tests and include various charts and graphs -- that even I don't understand. If you look at when the test was performed... you'll see a 3 years difference... so the manufacturer (Marantz) could have improved their power supply design over the term. In any event, Marantz is usually "expected" to be close to the claimed WPC. For what it's worth... I trust Sound and Vision as a truly unbiased reviewer. They don't shy away from saying bad things about bad receivers/equipment. Unlike the mainstream magazines. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1917 Registered: Dec-04 | As expected, Rotel is right on the money. Of course, the smoke chuffing from the left hand speaker port told me that, no clipping and surprisingly, no distortion(ok, that I could hear)but the neighbor said it was fine. When manufacturers follow the guidlines(such as they are) the amp is run into 1 channel, at a fixed tone and a fixed impedance. Uh huh. Even at a fixed impedance into ALL channels, this is Kief. I wanna see the unit run 5x 4ohmspeaker, with wild impedance swings before I buy the sucker. I offer my basement as a typical listening environment for makers of mid-fi stuff, with the spl and scopemeter handy. Signed, Made in Missouri. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8079 Registered: May-04 | I knew a maid in Missouri once. Unusual girl, she wanted to show everybody everything. |
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New member Username: ShawnharmanPost Number: 5 Registered: Dec-05 | I knew harman kardon had it in them. very good units. I have the AVR-325, Its pretty cool to just find out I just gained 21 watts. |
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Gold Member Username: Edster922Abubala, Ababala The Occupation Post Number: 3754 Registered: Mar-05 | Every once in a while I post that same S&V chart on audio forums whenever a newbie who's obsessed with wpc numbers pops up (fairly often, alas), just use a different link: http://www.geocities.com/Area51/Hollow/3401/ratevsac.htm?20055 Geekboy's link is a little bit more recent though, goes to September 2004 while mine ends at April 2004. I wish they would add newer models, many of those are long out of production. |
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Gold Member Username: Edster922Abubala, Ababala The Occupation Post Number: 3755 Registered: Mar-05 | geekboy wrote: "For what it's worth... I trust Sound and Vision as a truly unbiased reviewer. They don't shy away from saying bad things about bad receivers/equipment. Unlike the mainstream magazines." Yep, they are about the only print audio magazine to review one of the Panasonic digital-switching receivers and gave it a pretty good (though not ecstatically-raving like SOME people, lol) review. http://www.soundandvisionmag.com/article.asp?section_id=3&article_id=806&page_nu mber=1 |
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Silver Member Username: GeekboyTampa, FL United States Post Number: 443 Registered: Dec-03 | Edster: I just looked at that report and the Lab Test (in PDF). It seems this 100W x 7 receiver only did 77.4W x 6 and S&V only did a 1kHz tone at 8Ohms. I think it does better than MOST receivbers which advertise 100WPC x 5/6/7... but still shows that most receivers still don't meet their advertised numbers. It was also only 87.8W into 2 channels. The closest it came to 100W was with 1 channel driven (91..2W). The reviewer also cautioned with 6Ohm speakers as the power was nowhere near the spec, and 4Ohm was not advisable. I think these DPR receivers have come along way, but still have some kinks to be worked out. I think they are great in most home theater applications. Especially where size and "heat dissipation" (or generation) matters. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1928 Registered: Dec-04 | Good thread, folks! Jan I owe you a beer for that laugh at the right time.Jolly Good! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8090 Registered: May-04 | Remember, Nuck, Parker thinks us the Buffoons of Cahoots County. Poor Parker, its such a shame when they have to remove your sense of humor at birth. Odd isn't it? How Parker and Wiley came and went in the same time period. You don't think ... ? Nah, that would be psychotic. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1942 Registered: Dec-04 | But I've never seen them together, looking for us together, so altogether, uhh... I'll call back when I get it together. |
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New member Username: StefanomDublin, CA United States Post Number: 5 Registered: Apr-06 | "Just to provide further proof, I remember the Sound & Vision report of the Onkyo TX-SR901 about a year back. Onkyo claimed that their $1600 receiver was capable of 125W x 7, but actual bench tests showed the sucker clipped at a mere 56W when 5 channels were driven." Just to clarify this statement, it isn't that the receiver clipped at 56wpc, but it went into protection mode. Under normal operating conditions, it wouldn't have that problem. A lot of the receivers with obscenely low ratings, such as the Marantz 7200, I would guess have similar problems. |
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Gold Member Username: Edster922Abubala, Ababala The Occupation Post Number: 3758 Registered: Mar-05 | "Edster: I just looked at that report and the Lab Test (in PDF). It seems this 100W x 7 receiver only did 77.4W x 6 and S&V only did a 1kHz tone at 8Ohms. I think it does better than MOST receivbers which advertise 100WPC x 5/6/7... but still shows that most receivers still don't meet their advertised numbers. It was also only 87.8W into 2 channels. The closest it came to 100W was with 1 channel driven (91..2W)." Actually this was the only weak point of the review. See the Panny is speced to do 100wpc at SIX ohms. As you increase the ohms, the wpc numbers naturally decrease. So 88wpc at 8 ohms is pretty good if it claims 100wpc at 6 ohms. Panasonic is guilty of a bit of marketing hocus pocus here, they would've been more honest to advertise it as 90wpc at 8 ohms, but I guess they figured "100wpc" is the magic number for a lot of newbs shopping audio. Also it's kind of funny that the S&V lab report says the Panny "does not perform to spec at 4 ohms"---because it was never speced to perform at 4 ohms! In fact I think somewhere in the xr55's manual it specifically cautions against using speakers with under 6 ohms impedance. |
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New member Username: JawPost Number: 3 Registered: Mar-06 | And, Harman Kardon only references 8 ohms on the back of their receiver, in their owners manual and service manual. No mention of their vaunted capability in driving 4 ohms. Then, Stereo Review's/Sound & Vision cannot even spell Harmon Kardon correctly; so much for their credibility. Then, we dwell on the fact that only 10-15 watts are normally used by a receiver to drive speakers while emphasizing the importance of true disclosure because too many companies are punking out on their reported real mega-wattage to begin with. And, there is to begin with, no mention in this thread of what the speaker sensitivity, ohm rating or room size to be driven by said true wattage of the receiver is. Then, imagine the hysteria I had to endure in finally registering on this board. Edster, I promise you, there has never been anything wrong with your documentaion, hearing or opinions on the Panasonic. In fact, you opened up the board to a digital consideration. In light of all this, I forgot what my point was. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8097 Registered: May-04 | "there is to begin with, no mention in this thread of what the speaker sensitivity, ohm rating or room size to be driven by said true wattage of the receiver is." More than likely, that would be due to the fact none of those factors are of any consequence to the results of the test. If I understand correctly, the review was merely looking for the test bench wattage numbers obtained vs. the advertised wattage. They were not making a recommendation regarding which amplifier might drive which speaker to any specific level. These are not THX certified recivers and do not have to meet any minimum SPL specifications to be held accountable. I would guess the thrust of the article(s) would be to have the consumer judge products a bit less based on specifications than many people are wont to do. My question would be whether they suggest a viable alternative to reading specs for someone trying to purchase a new system. Do they have an audition process the consumer can use to feret out the sub-par equipment? Otherwise, once these models are discontinued, the conusmer is back to a guessing game as to which models do what properly. However, adding sensitivity or nominal impedance of an "ideal" speaker to these test results would still be inadequate information if the suggestion were how to match speakers to an amplifier. Since there is no such beast as the "ideal" speaker, anything other than the one model chosen as the target for the test would leave far too many people with no better understanding of the matching process. Unless, of course, another article were devoted to that topic. That article, by necessity, would require another article concerning room interaction and the speakers you might choose. I can understand why this information was left out of this article. Not to disagree too strongly, but we shouldn't dwell at all upon the small amount of wattage typically required to play at "normal" levels. These are all home theater receivers and will be expected to deliver full wattage on demand when that explosion or car wreck takes place on screen. With discrete information in all channels, it would be of some consequence whether the amplifier produced 100 watts or 56 watts. Though, in reality, what is the audible difference we would hear? There seems to be a diachotomy between suggesting specs do not tell us everything and (possibly) then not informing the reader that specs simply don't tell us enough. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1953 Registered: Dec-04 | And besides, if we are dealing with maximum output wattage only, there is no consideration of the receivers recovery time from delivering that cannon shot before the next comes along, which really points out the depth of the power supply. In real wworld listening, thesevolumes can be deafening, unless in a large room, or theatre, but can the unit do it time after time, without the receiver looping into distortion due to a lack of bleed down time?(if wrong term, right idea)? |
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Silver Member Username: EramseySouth carolina United States Post Number: 454 Registered: Feb-05 | Nuck I think you are referring to the slew rate of the power supply. For most home theater receivers this will equate to about 40V/microsecond. For powerful home amps such as the Aragon this can be as high as 60V/microsecond. Taken from NAD's website" Wattage is an incomplete measurement of amplifier power, in terms of sonics and dynamics it's current that counts." This basically sums it all up. Many receivers such as the Onkyo boast high wattage ratings and claim to be a "high current design" but in reality are quite the opposite. When faced with complex speaker loading such as driving multiple surround speakers, the Onkyo,as well as other brands, will reduce their power output per channel by less than half of their stated FTC rating. This discrepancy is the direct result of current limiting by the power supply, to protect the amplifier which results in limited sonics and sound quality. Other than improper speaker wiring protection, Harman Kardon uses no such antiquated methods in their amplifier and power supply design. A receiver that goes into protection mode,when faced with a given speaker load indicates a problem, given that it cannot be assumed that less volume or less time of use will correct this. The biggest gripe I have with the audio mags is that they are more and more frequently using sine test tones to guage amplifier power ratings,which is basically an unrealistic torture test for an amplifer that will never be encountered in actual use, instead of making their measurements with the receiver connected to a speaker load of somewhat known parameters. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1955 Registered: Dec-04 | Thanks, Eric. Some sort of dynamic load would seem to make sense, varying within a given range of impedance and frequency. But now we have to change the industry, no? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8104 Registered: May-04 | ER - While slew rate would be a small consideration in the alternative specifications the consumer needs, it still doesn't tell us much in terms of how the amplifier will handle dynamic passages and certainly says nothing regarding the sound quality of an amplifier. The slew rate for a 25 watt solid state amplifier should, in order to reproduce the dynamics of most music - and most especially the needs of ht - be the same as that of a 100 or 500 watt amplifier. As you said, all "well designed" amplifiers (solid state, at least) should aim for somewhere around 60V/msec. Depending upon the design of the power supply. However, slew rate still doesn't tell us much about how an amplifier will deal with a large dynamic peak which taxes the outputs. I would suggest a glance at the dreaded "peak power" specification while acknowledging its severe limitations to inform also. However, an amplifier with a fairly loosely regulated power supply can probably swing enough voltage, and some amount of current, during dynamic passages to meet the short term goals of "clean" reproduction. Under the inadequate but "correct" conditions (a speaker which requires little current drive comes to mind), a small 25 watt amplifier can manage almost triple that number on a very short term basis. Thus, the 100 watt RMS amplifier can sufficiently deal with the dynamics of ht use while only producing 56 watts RMS on a test bench assuming the power supply is designed for such swings of voltage during its operation. Two points should be raised here. First, the "peak power" specicifcation has suffereed mightily from more abuse at the hands of audio marketing departments than possibly any other specification in audio. The reason the FTC banned its many variants way back in the 1970's was the amount of inadequate information it provides the buyer and the many ways it can be used to mislead the consumer. The many problems of moving a loudspeaker to adequately reproduce a signal are not in the least addressed by this spec - nor are they addressed by most specifications typically provided to consumers. It is, however, peak power is a fact of amplifier performance and can be useful in covering up many of the faults of modern amplifier design. A point, I might add, not at all lost on NAD's marketing department. Also, not having read the article(s) from which these original numbers where presented, I can only assume the intent of the article was to point out that many manufacturers are not playing on a level and equally difficult to manage playing field. They are, in all intents and purposes, violating the rules for their own gain against the benefit to the consumer. As it stands, however, the numbers alone still tell little of the actual story behind the specifications a consumer will encounter. My advice to buyers still stands. Buy the amplifier/reciver with the least amount of watts and features per dollar spent. The likelyhood the money will have gone to better quality parts which will adequately reproduce music in a pleasant fashion is much higher with such a design. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1956 Registered: Dec-04 | But what if it is not powerful enough for the room? |
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Bronze Member Username: NadzCalifornia Post Number: 32 Registered: Aug-05 | The ironic thing about Blazers post is NONE of these manufactures except for NAD and Rotel claim ALL CHANNELS driven. The manufactures claim an output times a number of channels but they do not claim it with all channels driven. So in no way are they lying to anyone. These receivers will output there rated power into at least one channel driven most likely two. The number of channels listed will output there rated power just not all at once. Which is completely unrealistic in the first place. People need to learn how to read specs. Look closely at all the manufactures manuals. None them claim all channels driven. Except for NAD and Rotel. Here is great article about this very subject. http://www.audioholics.com/techtips/audioprinciples/amplifiers/allchannelsdriven .php |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1961 Registered: Dec-04 | Thanks NADz, and the test proved that fact, as the lesser pieces proved feeble at 5 channels driven. Outlaw are also happy to print all channels driven, too bad we cant see them in the test soon. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1962 Registered: Dec-04 | In fact, how about a comparo to power amplifiers, even if the procedure seems to be somewhat questionable? |
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Silver Member Username: My_rantzAustralia Post Number: 476 Registered: Nov-05 | After their dismal performance with the Sr-7200, Marantz now guarantees a minimum of 70% of its advertised power rating at all channels driven. Bench tests on several models have proved them to be putting their money where their mouth is with several models doing way, way, better than that. For example the SR-7500 (rated 105w @ 8ohms) tested at 130w for two channels and 90w at 5 channels driven (www.homecinemachoice.com). |
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Silver Member Username: EramseySouth carolina United States Post Number: 455 Registered: Feb-05 | Your right Jan, the slew rate will be of little use in determining how well a receiver will handle a complex speaker load, I was merely attempting to offer an explanation to Nuck. Harman Kardon rates it's receivers in surround modes on an individual basis, however this is a more honest spec which is x/Watts @20Hz-20KHz into 8 Ohms, than most manufacturers who will use the fudged X/Watts @1Khz. They also give the maximum power consumption, with all channels driven, which is maximum the unit can consume with AC input before the unit goes into clipping and/or a fuse is blown, so this in effect is an all channels driven disclosure. It is also important to note that during playback of surround material, very rarely are all channels called upon to deliver full equal amounts of power anyway. This trend of audio magazines when testing amplifiers and receivers to use sine tones, I find disturbing. Very few powerful amplifiers,let alone a receiver, will cope well with this type of testing which is completely unrealistic and ultimately meaningless to the consumer, who would understand a receiver or amp tested with a speaker of somewhat known characteristics much better as I said previously. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8107 Registered: May-04 | "But what if it is not powerful enough for the room?" Buy a smaller room. Try for an "L" shape. "The number of channels listed will output there rated power just not all at once." Not necessarily. That would require all channels to be designed identically, something a manufacturer looking to cut corners might not choose to do. Since most lower priced ht receivers still use output IC's, rather than discrete output devices, for anything other than the main front array, it is actually unlikely all channels would output the rated power stated for the front channels only. Certainly the rear channels from a chip amp won't be able to drive difficult loads as effectively as a discreet amplifier might when current is required. " Marantz now guarantees a minimum of 70% of its advertised power rating at all channels driven ... " Why not just publish the 100% they actually manage? That's an odd claim to fame. Kind of like the Texas Rangers claiming they finished 70% of their game schedule last year. They lost that 70%, but they stayed until the end of the game. Whoopee! ER - I have to admit, I've never looked at the maximum power consumption sticker on an amplifier to decide whether the manufacturer has turned out a piece of junk. To me, that's somewhat like looking at the tire size before deciding which car to buy. I'm not sure why you find the use of sinewaves "disturbing". And I'm at a loss as to why any amplifier would have a hard time coping with sinewaves. Particularly, very "powerful amplifiers". This is not a "trend" but rather a classic test bench practice and amplifiers have been rated for RMS power using sinewaves for I don't know how long. I have no disagreement that sinewave and load resistor based measurements are all but meaningless to the consumer, but what's your alternative? Firstly, there is no such thing as a "speaker of somewhat known characteristics" and the measurements taken with the amplifier driving any speaker would be largely applicable to that speaker only. Secondly, even a relatively small change in the crossover configuration of the speaker you chose rather than the "known speaker" could result in a drastic change in how the amplifier would need to perform. I wholeheartedly think RMS, THD and so forth should only be used as filler when the designer has run out of things to say relevant to the design. The less there is to say about how the amplifier was designed, the sooner you'd see the specs. Of course, this too would be misleading since the mass market receiver companies have those "magic" circuits they invent each and ever year. Oh, well, eeney, meeney, miney mo'... |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8108 Registered: May-04 | Nuck - You know why you want an "L" shaped room if what you have is too big; don't you? That way you can only listen to the "|" part or the "_" part. So you get a whole lot more sound when you're not listening to the part of the room you're not using. Smart; huh? |
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New member Username: JawPost Number: 4 Registered: Mar-06 | Uh, by the way, a late thanks for your response. Now, while reading this stuff, I think my point was something along the lines of Compared to What, In What Application, What Does It Mean In The Real World, and how important Is The Truth In Lending Act For Power Ratings, anyways? This seems to be the way the information has unfolded and gives me some perspective. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8111 Registered: May-04 | Yep! |
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New member Username: JawPost Number: 5 Registered: Mar-06 | At least I'm paying attention. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8114 Registered: May-04 | Yep! |
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Silver Member Username: EramseySouth carolina United States Post Number: 457 Registered: Feb-05 | From a purely electrical standpoint, remember that no device can produce more power than it consumes- power in must equal power out(approximately). "Most manufacturers use ic amps for their rear channel outputs"- unfortunately all too true. This,however,is not the case with HK even with the entry level models as HK does not use ic's any where in the amplifier signal path and uses decent quality, high current rated output transistors for all channels. Your right sine tone testing is the standard as of late, but reactive load testing is certainly feasable, provided it is done properly and the reactive load does not contribute to the distortion figures themselves. This type of testing would more resemble an actual loudspeaker, rather than the unrealistic non inductive fixed 4 or 8 Ohm resistor. |
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Silver Member Username: GavincummNew York USA Post Number: 878 Registered: Feb-05 | geekboy thinks that S&V is unbiased? remember they think that Bose Acoustimass / lifestyle speakers sound good, with great bass! how is that for being unbiased? |
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Silver Member Username: GeekboyTampa, FL United States Post Number: 444 Registered: Dec-03 | Gavin wrote: geekboy thinks that S&V is unbiased? remember they think that Bose Acoustimass / lifestyle speakers sound good, with great bass! how is that for being unbiased? Let me position this. Because a reviewer believe that a product is good doesn't mean it's an overwhelming endorsement of the product, it's price, it's place in any particular application. I've owned Bose before in the past and I thought they were good. Later, I found that I could have better speakers for the same price. I say that S&V doesn't arbitrarily try to be nice to the manufacturers by pumping up otherwise poorly made or sounding equipment. Bose is decent, has a place, and has a great customer service reputation. Would I recommend Bose for "some" people, yes. Is Bose a quality built speaker, yes. Would I use them... NO! Bias, by definition, only means that they have a strong propensity to show stronger liking to them. I think S&V is neutral at best. Neither left nor right. They (S&V) are neutral. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8126 Registered: May-04 | "Is Bose a quality built speaker, yes." ??? Sorry, nothing I've seen from Bose has shown any intention to use quality parts. Without a decent level of quality in the components you use, you are not going to end up with a quality product. That is exactly why you found out you could have better speakers for the same price. Not trying to turn this into another Bose bashing thread. Just stating some facts. What hasn't been mentioned yet is Bose's advertising budget and marketing scheme. Sound and Vision is the offshoot of Stereo Review, a magazine that never found an advertised product it didn't think represented "good value". I understand SV's target audience is the average Bose buyer. Therefore they would be killing two birds with on ill placed stone to suggest a speaker with a 1 1/2" paper cone tweeter is not worth consideration. I think you can buy a similar tweeter for about $0.19 in bulk lots. |
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Silver Member Username: GavincummNew York USA Post Number: 882 Registered: Feb-05 | the only speaker that I heard with a cone tweeter that I thought sounded OK were the Cambridge Soundworks model 6. I think this is the correct number, as if memory serves me correctly the 6 was the larger of the two (6 and 17). the fact that they discontinued this speaker was a shame, as nothing could touch it for the price. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8137 Registered: May-04 | My understanding of how the Cambridge speaker came about was Kloss wanted to have a "redux" of his KHL Model Six. The KLH came along in the early 1960's and at that time had a cone tweeter. |
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Silver Member Username: HawkHighlands Ranch, CO USA Post Number: 790 Registered: Dec-03 | Hey guys, I just saw a new twist to the story. In looking up the specs on a new Pioneer 815, they claim that they get the rated power (110wpc) across all six channels, but it is carefully couched as "110 wpc x 6 @1kHz with 1% distortion." Thus, they cannot meet the rated power across the entire audio range. The last time I remember seeing this dodge was in the '70s. I wonder what this thing clips at when driving all channels? |
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New member Username: Mr_smithCanada Post Number: 4 Registered: Mar-06 | Hey Hawk, You may find this somewhat ironic, it's from the Outlaw 1070 receiver specs at: http://www.outlawaudio.com/products/1070.html
That's right...they've specified both the all channels driven rating and the carefully couched rating. It must have been some compromise between marketing and engineering  |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 1141 Registered: May-05 | One of my favorite specs is the Denon 2.1 HT system they sell at Best Buy - 50 watts x 2, 4 ohms, 1kHz @10% THD. I can't find the specs anywhere online, but the that's what the little info sheet says. The only specs I can find online say 50 x 2 @ 4 ohms. 10% THD? You've got to be kidding me. The LGs, Panasonics, and a few other HTIBs are right around the same THD level. Isn't 10% THD way past the level of clipping? |
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Silver Member Username: GeekboyTampa, FL United States Post Number: 445 Registered: Dec-03 | Stu wrote: Isn't 10% THD way past the level of clipping? Forget 10%. Audio designers will tell you that at 1% THD, all bets are off!!! That means at 1%, there's so much distortion, it's highly undesirable. What they are trying to tell you with that 50watts x 2 into 4 homs with 10% THD... is that at about 1/2 watt, you're at 1% THD ( )... The ohter telltale is the 50W into 4 ohms. That's terrible! 4 Ohm speakers require more power and thus, you'll usually an amplifier rated at 8Ohms at a lower number, then 6 ohms at a higher number, and 4 ohms at still ahigher number! (Has to do with the load presented to the amplifier. So, at 8Ohms, that receiver would output 25W... at 10% THD... sheesh) But what do you want from mass market HTIB systems? I don't know about you... but I don't know what "distortion" is anymore. Every since I got rid of those Bose speakers! |
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Silver Member Username: GeekboyTampa, FL United States Post Number: 446 Registered: Dec-03 | Self correction... 4O speakers don't require more power than 8O speakers. I was just getting a little too excited! Where's that post retraction button anyhow? |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 1143 Registered: May-05 | Geekboy - If it were a goor power supply, the power would double from 8 ohms to 4 ohms. Actually, even good power supplies don't always double in power form 8 to 4 ohms, only the best ones do. I highly doubt the numbers would change significantly between 8 and 4 ohms on this POS. 50 @ 4 ohms probably looked better than 39 @ 8 ohms (I don't know what the exact number would be) to the marketing guys. Also, 50 watts @ 10%THD probably looked better than 12 watts @ .05% "What do you want from mass market HTIB systems?" Exactly. That's why all of my meager budget is tied up into a quality 2 channel system. I'd rather have two very good channels than 5 or 7 crap channels. When the budget goes up, I'll still stick with 2 channel. |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 1144 Registered: May-05 | Posts crossed... |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8255 Registered: May-04 | I wouldn't get too vexed over 10% "distortion". Many low frequency drivers will produce substantial amounts more harmonic distortion than that on relatively simple material. The intermodulation distortion of a typical woofer could be through the roof by most estimates of "proper" or "acceptable" specifications for an amplifier. And surely the phase distortion of most loudspeakers is far more audible and constant than the instantaneous and ever changing harmonic distortions of an amplifier. Even when the amplifier is in mild clipping. Much of what you hear is the result of what happens immediately after the amplifier produces 10% harmonic distortion. Remember it is a dynamic signal you're referring to when you talk about music. It has little to do with what you will see on an oscilloscope. While THD is what a manufacturer should be referring to on any spec sheet where power is stated, harmonic distortion is quite often fairly benign in music reproduction simply because it is harmonic content being added. The addition of certain predominant distortion products can make a "total" harmonic distortion spec quite misleading. To adequately discuss distortion you have to consider all the ways the signal reaching your ears can deviate from the original. IM, TIM, Doppler, digital jitter and phase distortions all would appear to be more disturbing than a simple harmonic distortion spec would indicate. http://www.klippel.de/aura/ http://www.stereophile.com/reference/1104red/index.html http://www.stereophile.com/reference/1291jitter/index.html http://search.yahoo.com/bin/search?p=audibility%20of%20distortion http://www.stereophile.com/asweseeit/572/index.html http://www.stereophile.com/searchresults/index.html?stype=X&terms=audibility+of+ distortion While quoting power output at 10% harmonic distortion content is somewhat misleading, it is not what I would be concerned with. It is merely marketing at it's best. |
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Silver Member Username: GeekboyTampa, FL United States Post Number: 447 Registered: Dec-03 | Jan wrote: ... simply because it is harmonic content being added... That makes sense to me as harmonics aren't always "noticeable". I wonder what the true correlation is to Harmonic Distortion versus Sound Quality... I mean the kind of distortion that's noticeable. So what's worse... 10% THD at 200W or 1% THD at 70W... I usually will look at the specs and make sure the THD is below 1% at "rated power" for any amplifier. Is this the way to go? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8257 Registered: May-04 | " I usually will look at the specs and make sure the THD is below 1% at "rated power" for any amplifier. Is this the way to go?" You might be disappointed if you begin looking at tube power amps. I would ignore THD completely. Any competently designed amplifier will have THD specs that are acceptable. There's far more to it than any paper spec can begin to suggest, but as I said, it is what happens immediately after the amp clips that is often the most important factor in amplifier sound. I don't know of a spec commonly quoted which indicates this, you've got to look pretty far into the measurements and you'll still only know a bit more than before you started since the measurements are made with static sinewaves and not music. |
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Gold Member Username: NuckPost Number: 2151 Registered: Dec-04 | Where at clipping, the amp is quite liable to 'run away', at the feedback loop, if not protected. Cheap amps come here to die. |
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