Prima Luna Prologue One question
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New member Username: Philipt95148Post Number: 7 Registered: Jun-06 | Hi, Just completed set up of Prima Luna amp/Rega Apollo CDP and Monitor Audio RS6 speakers. The speakers positive was first connected to the 4ohm output of the amp. The sound was warm, full range at first, then faded out in the low frequency over a while so I ended up with next to nothing for bass. I switched to the 8ohm output (per Prima Luna's manual) and got the same thing. Good at first and then next to nothing for bass. When I first switched on the amp, I noticed that 2 of the tubes never lit up like the others, they stay like that. Could this be the reason? Tubes not working? Could it be that the speakers need more running in time to settle down? It is just so weird! All the components review with great bass response and I would not imagine that the sum of its parts is a lot less than that! Anyone got any idea? I'd appreciate your answers. Thanks Philip |
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Gold Member Username: John_aLondonU.K. Post Number: 4335 Registered: Dec-03 | Philip, All four output tubes/valves should glow equally. In your place I would first make sure that all eight tubes/valves are seated correctly in their sockets. If the sound and "no-glow" problems persist, then contact the dealer. It sounds like your amp is still under warranty. That is a nice system. |
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Bronze Member Username: Leafs_fan_4_evaToronto, Ontario Canada Post Number: 30 Registered: Jun-06 | hey |
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Bronze Member Username: Leafs_fan_4_evaToronto, Ontario Canada Post Number: 31 Registered: Jun-06 | wuts up guys |
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Bronze Member Username: Leafs_fan_4_evaToronto, Ontario Canada Post Number: 32 Registered: Jun-06 | hey john do you live on the east end of london? |
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Gold Member Username: John_aLondonU.K. Post Number: 4338 Registered: Dec-03 | John; Yes. |
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New member Username: JmstankiPost Number: 1 Registered: Jul-06 | Hey Phil, I'm interested in the combo you put together--I was actually thinking about getting the same thing. Have you gotten things fixed and are you happy? Also, what other equipment did you look at before you bought? I have monitor rs6 as well. I'm also considering creek 5350 se and naim nait 5i both potentially with Apollo CD player. What do you (or anyone else!) think? |
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Bronze Member Username: WaydownPost Number: 58 Registered: Jun-06 | cool |
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Gold Member Username: NuckPost Number: 3299 Registered: Dec-04 | Did Phillip sort out his dark tubes, I wonder? JS those are 3 very very different amps you have mentioned there. So far as comparing, it's apples and undergarments. The PL is going to deliver smooth untainted sound without pushing the bass to the front of the stage. As described to me by Stu here 'if you like the Rotel presentation, you will love the Nait'. Ideally, no setup will taint the music away from the original recording, but presentations favor some aspects more than others. Nice selection, BTW. |
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New member Username: Philipt95148Post Number: 8 Registered: Jun-06 | Hi James/Nuck, Sorry for delay, been out of the country, just got back this w/e. I am none the wiser, I am afraid. My dealer said that if the 2 12AX7 tubes did not work, I would not get any sound from the amp and that if you look carefully, you should see it glow, true, if you look close enough, you can see the glow. Before I left for my trip, I disconnected the Apollo and hooked up an old 15 years old beaten up Panasonic portable CD player, and then a Timex clock radio with a CD player, just to go through the process of elimination of a bad source. Low and behold, I got deeper bass coming out of the speakers. Contacted dealer and shipped Apollo back to him for A/B comparison, I got a call from him to say that my Apollo sounds just like the one he has in the shop ? So now I hooked up my DVD/CD player and got good bass from it. So I have to wait for the Apollo to come back to compare again. When I was chosing speakers, I heard the Vienna Acoustics Beethoven and Mozart, and loved them for the really deep sound stage and low frequency, especially for violin pieces but just don't have the budget for them. On the same piece of music, the RS6 could not match the Vienna Acoustics. Maybe I should have after all?/?? I am not entirely sure that I am happy with the whole system right now. Nuck is right, the PL is very smooth, without pushing the bass to the front. Maybe that is what I am hearing, on Miles Davis Kind of Blue, So What, the bass player sounds like he is sitting back in the room and is just feathering the strings as opposed to groovy with band. Or maybe my room is particularly difficult for bass set up, I will show a pic next time of the speakers placement. It's just weird! |
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Gold Member Username: NuckPost Number: 3338 Registered: Dec-04 | Good update, Philip, thanks. Really quite odd with the Rega, indeed! Let us know when you try it again, will you? Clock radio, ROFL! I bet Rega is a tad red in the clock about that! |
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Gold Member Username: John_aLondonU.K. Post Number: 4397 Registered: Dec-03 | I suspect you have the wrong sort of equipment for your needs, Philip. You might prefer an amp with tone controls. Alternatively, a graphic equalizer will allow you to experiment with the frequency spectrum. I doubt if you are truly getting deeper bass with the clock radio; the speakers will set a limit of about 38 Hz on what you hear, anyway. More likely the radio has a bass boost, like a CD Walkman. It would simple to test that. There are a lot issues here. It all comes back to the question of what does one want, or expect, from a hifi system. |
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New member Username: Philipt95148Post Number: 9 Registered: Jun-06 | Hi John, It's true what you said but the curious thing is that I did not get bass out of the Apollo. For the moment, I hook up my Sony DVD/CD player to the PL/RS6 system and I am getting bass out of that. My room is 15 x 14.5 x 8.5 and I suspect it is part of the issue. Prior to this PL/Apollo/RS6 set up, I had Audio Analogue Puccini amp/Paganini CDP/Sonus Faber Concerto which I bought when I was living in Ireland. I had similar response from that system when I moved to this new house, ie: very bass shy, but it was oK in Ireland in a smaller apartment with carpet. Nuck, what's ROFL? It sounds funny but I couldn't figure out. |
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Gold Member Username: NuckPost Number: 3342 Registered: Dec-04 | Roll On Floor Laughing, Philip. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8838 Registered: May-04 | . "My dealer said that if the 2 12AX7 tubes did not work, I would not get any sound from the amp and that if you look carefully, you should see it glow, true, if you look close enough, you can see the glow." That's true but tubes will still "glow" when they are not working properly. Within a circuit all similar type tubes should have the same look to them when you view them in a darkened room. All 12AX7's in the pre amp stage of this integrated should glow at the same level under those conditions. If one appears to be significantly dimmer than the other, you have a problem. A pair of 12AX7's in this amplifier's output section might not look similar to the tubes in the pre amp section due to a difference in input voltage. A tube that shows no signs of life (no glow) is merely indicating a tube within or having an open circuit. Worn out tubes and defective tubes often glow but do not produce the correct voltage and often look different than brand new tubes. So your adviser apparently gave too simple an answer. However, since you get bass with other inputs, the possibility of a bad tube is minimal. (It would be a good idea to have a spare pair of 12AX7's on hand, however, for troubleshooting.) Since you get bass with other sources \in the same room this would not indicate a room problem. Unless you change something else when you installed the new source. New cables? Move the speakers? Let's look at this sentence; "Maybe that is what I am hearing, on Miles Davis Kind of Blue, So What, the bass player sounds like he is sitting back in the room and is just feathering the strings as opposed to groovy with band." Well, yes, in an acoustic jazz combo the bass player is typically towards the rear of the stage. Most usually this would be the case for an acoustic bass rather than an electric bass. If you are taking a rock or contemporary jazz recording to be your, "The sound was warm, full range at first, then faded out in the low frequency over a while so I ended up with next to nothing for bass", and the Miles Davis' recording to be your, " ... the bass player sounds like he is sitting back in the room and is just feathering the strings ... ", then you are once again comparing two dissimilar items. Acoustic bass seldom sounds like an electric bass either in presence or in placement. You apparently demonstrated to yourself the system can produce the bass you prefer in this room. You are now left wondering if the source player is at fault. You wasted your time shipping the player to the dealer. Any local dealer would gladly have shown you what your player sounds like compared to their player. You should have carried your deck down to the nearest dealer and asked for that comparison. When you get the Rega back, if this problem still exists, you should carry your deck down to the nearest dealer and ask for a comparison. If you favor the other guy's stuff, you have a problem to deal with directly with Rega. You might possibly be better off buying some other player and forgetting the Rega. This might be what the Rega sounds like. However, to solve any problem like this you have to finally stop flapping your wings and think logically. Eliminate one possibility at a time and only one possibility at a time. Everything else has to remain consistent. If the room has bass when you play another source, the room is not the problem. If the system has bass when you play another source, the system is not the problem. If the Rega sounds like all other Regas, the Rega is functioning properly. If the Rega doesn't sound like other players, you might want to have a different player. To give any further advice, I would like to know what you mean by "the bass faded out". Does this mean it went away while you were listening to one recording? The bass wasn't as strong when you went back to the same recording two nights later? Or, does this mean not all recordings sounded the same? . |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8839 Registered: May-04 | . "I had similar response from that system when I moved to this new house, ie: very bass shy, but it was oK in Ireland in a smaller apartment with carpet." With this sentence, you've confused the issue once again. Did you ever get good bass response with this system in this room? Did you try various sources and find the player was at fault? There must be a logical reason you hear what you accept as good bass in the same room but not with higher end equipment. Have you walked the room to locate standing waves? Is it possible you have a standing wave at your listening position? . |
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New member Username: Philipt95148Post Number: 10 Registered: Jun-06 | Hello Jan, Thank you so much for your very detailed explanations and analysis. I shall try my best to answer all your questions here. The dealer is Kevin Deal of Upscale Audio, the other half of the PL amp, so I would have to trust him for his advise. I bought the PL and Apollo from Kevin, the speakers are from Magnolia Hifi in San Jose, I would have bought all from Kevin but he does not carry MA speakers anymore. I did buy the amp as an open box item from the CES show. Kevin also supplied interconnects, DHLAbs BL-1 MkII and speaker cables, DHLAbs Silver Sonic T-14. I did not change cables when swapping things around, the only extra is a Y adaptor stereo phone jack to plug in the portable CD player. For the Sony CD/DVD player, I used the DH Lab interconnects. I did not think of taking the CDP to a local dealer, I was doing as you explained, eliminating a suspect bad source and when I got good bass from the portable CDP and the clock radio, I came to the conclusion that the Apollo was a faulty unit and not the amp or speakers. With regards to the previous system, it is hard to tell Jan, since it stayed in the box for a long time whilst I was moving country and house, so when I finally hooked them up, I think the bass is very light, compared to how I remember it in Ireland. So no I don't think I ever got good bass with this system in this room. It was only good in Ireland in a small apartment with carpet. I did not try other sources like I did this time. As for the "bass faded out", I meant it went away whilst I listen to the one recording. Can you explain the standing wave issue and how do I test this in my room? Here is a pic of the room and set up, since the pic was taken, I have moved the speaker further out and away from the curtains. I also got a speaker set up CD from Kevin, I shall try this and report back.  |
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Gold Member Username: John_aLondonU.K. Post Number: 4401 Registered: Dec-03 | In my first response I assumed, obviously incorrectly, that it was the output tubes that glowed with different intensities. I concur that the input tubes do not need to. They should seem matched in pairs. That's normal. On my PL2 it is the middle two that are dim; the outer two are brighter. I mentioned this thread on another because it seems to me we have the recurrent problem of "what do we expect from HiFi?". In this case it takes the form of "Where should the bass player be?" My answer would be "where he really was". Assuming that is what the recording engineers were aiming for, too. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8840 Registered: May-04 | . "Standing wave - a buildup of sound level at a particular frequency that is dependent upon the dimensions of a resonant room, car interior, or enclosure. It occurs when the rate of energy loss equals the rate of energy input into the system. This is what you hear when you listen into a sea shell." The bass sinewave rebounds off the rear wall and cancels the next sinewave coming toward the rear wall. More latter. . |
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Bronze Member Username: Mike3Lewisville, Tx USA Post Number: 27 Registered: May-06 | Thanks Jan, I had a dealer who sold me my isoloation cones give me a brief but informative demonstration on how to set my speakers. He said to take my "Bass" speaker, either left or right did not matter, and place it up against the wall. Then slowly move it out and marking with tape where the bass came alive. After about 3 marks I had the "range" where to keep my speaker within. He then had me use the opposite speaker to line up the center point for the soundstage, informing me that I should not conclude that it would be situated precisely in line with the "Bass" speaker. He explained plumb bobbing and angle in / out. Now I understand why there are live and dead zones. It is so completely logical that I should have figured it out myself. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8841 Registered: May-04 | . Everyone has their own method of setting up speakers. Mine has been described on the forum in detail though I doubt I could find the link to that set up procedure. It invoves FM radio, laser pointers and tape measures. However, I suggest everyone wishing to get the best performance they have paid for should place "speaker set up" in a search engine and read the various methods described. There are four or five basic techniques I can think of and all will land your speakers in a slightly different location within the room. Your job is to read the methods to find what they are aiming for and then experiment with the techniques. Most people end up combining methods to achieve the goals they personally feel are important to themself. The main point of doing this is to have goals you feel are important. Standing waves occur in all rooms where the dimensions of the room are smaller than the lowest frequency you are trying to reproduce. Since low frequency sinewaves are often over thirty feet in height, most rooms have some sort of low frequency problems. Even when the room doesn't create a rock solid standing wave where the signal is totally cancelled at certain frequencies, most rooms will have peaks and dips where bass signals are amplified by room gain or minimized by room nodes. Just as important to where you place your speakers is where you sit. If you plop your chair down in the middle of a peak or dip, you'll not hear an accurate sound at certain frequencies. There are freeware programs which let you plot the rising and falling frequency response of a given room by plugging in the dimensions. . |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8842 Registered: May-04 | . PT - I didn't suggest the advice given was incorrect, just insufficient. You do have what appears to be a fairly lively room with dimensions which will have more problems supporting deep bass evenly across the bandwidth. However, you report obtaining decent low frequency response with the DVD/CDP, "So now I hooked up my DVD/CD player and got good bass from it." If the remainder of your system is in place and there were no other changes to the system when you inserted the DVD player, the room should not be the issue. One thing which has to be resolved is what you consider "good bass". Are we merely talking content and amount of bass? Are we talking depth of bass response? Clarity? Tunefulness and musicality? What is "good bass" to you, PT? As I said above, you seem to indicate the main part of the system is not at fault. You also indicate what would appear to be a room which can support sufficient low bass response for you to consider your current results "good bass". If you hear "good bass" with all but one component in line, that leaves very few variables to consider. If this is the case, I would suggest you spend some time working out proper speaker placement while you wait for the Rega to return. When it arrives listen again with the speakers set up as well as you can get them with your current player. Should the Rega still sound restrained in the lowest octaves, you will have to suspect the Rega is the offending piece. At that point take it to another dealer for a comparison. Or, ask a friend to let you play the Rega through their system. As long as you can trust the dealer/friend to make a fair comparison, this should tell you what you need to know. Unless what you have right now is not "good bass". Should you have doubts about the room (which I would not suspect with the reported response you have now), you can check for better room problems by moving the system temporarily into another room. . |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8844 Registered: May-04 | . Looking again at the picture of your room, I notice the system seems to be located in between the speakers on a short rack. Correct? And you appear to have hardwood floors. This isn't always the case, but you could possibly be on a pier and beam foundation. The Rega is a bit new to know if I'm on the right track, but let me make a suggestion. It might be a case of the Rega not preferring the siting you've chosen for the deck. Do you have any sort of isolation devices you're currently using? If the Rega checks out OK at the dealer and not at your home, there might be an issue of feedback interfering with the Rega's operation. Have you explored that option or did you just plunk the system down on the existing rack? . |
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Bronze Member Username: Philipt95148Post Number: 11 Registered: Jun-06 | Hi Jan, Regarding your question on what I consider "good bass". When I first reported the issue, it was "no bass" or that it "went away" after a while. "Good bass" at this point was merely yes or no that I have bass from the system, and not yet quality. I went home and experimented with speakers placement using the CD and set up instructions I got from Kevin, pretty much like Michael Wodek described. The track used is Jennifer Warnes "Ballad of the Runaway Horse" for bass and vocal focus. True enough, after a while I found the sweet spot for bass extension and voice, and to my surprise, the right/left speakers best position is not in the same spot relative to the room either side. I never knew this but I am so happy I found it. The bass is thumpy, woolly and undefined sometimes, but it is there. I will compare it to the Rega when it comes back this Thursday. So the answer to your second question on bass is that "good bass" to me is not the above. I am looking for tuneful/clarity/tight but also some depth when it comes to classical string music where violins and cellos are played. Jacqueline DuPre playing Mahler comes to mind. You are also right that my house is on a pier and beam foundation and it's a hardwood floor, total bad combination or what??? The rack is just a coffee table with not a sturdy thick glass top and the PL/Rega are just placed on top. I do have some isolation cones I will play with tonight. Now I only had a couple of hours to play with the system last night until my baby started to cry and I had to go and helped my wife (or she wouldn't let me play with it anymore  ) but I could swear that the bass went away (or decreased) after a while. Could standing waves be delayed and caused this after a while Jan? Also after a while I could hear crackles (like bad radio reception) in some pieces, bad tubes or bad recording? I read in the tube talk or elsewhere in the forum about "microphonic", could this be the cause, since the amp is in between the speakers? John A. The two 12AX7 in the middle glow dimmly. The two outer tubes are brighter. James S. How does your RS6 sound to you in your current system? |
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New member Username: JmstankiPost Number: 3 Registered: Jul-06 | Philip... My RS6 currently doesn't have much of a system. I know that NAD C542/C352 combo sounds not exactly true to the recording ("bright?") but is very rhythmic and pleasurable. I had C542 paired with cambridge audio 640v2 for a while but the 640/RS6 combo emphasized the high frequency detail which grated on my ears after 5-10 minutes so I took back the 640 and replaced it with C542. I have heard the RS6 with Naim separates/CD5i which sounded wonderful but that would be ridiculous because using $3000 amp to drive $1000 speakers just doesn't quite fit. So I'm planning my next move but need to sell NAD equipment first. The questions really seems to be prologue vs. Nait 5i and Apollo vs. CD5i. I do like the idea of soundstaging so I bet the tube we be better for this, but the Naim separates sounded very nice--I imagine Nait isn't an incredible step down. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8846 Registered: May-04 | . If the bass actually "fades away" while you are listening, there is a problem for a technician to look at. If this happens with the DVD player in the system, you've indicated another unit would be the culprit. This, of course, applies only if the bass does fade away with the DVD player also. That could indicate a biasing problem in the amplifier. But, you've got to narrow this down by eliminating the possibility of one problem unit at a time. So, if the problem continues with the DVD player, you've got more troubleshooting to do. Standing waves are either there or they are not. That isn't quite true as it requires the frequency where the room has a null to excite the standing wave. Obviously, if the standing wave occurs at 38Hz and you never play music with information beneath 50Hz, the actual standing wave can't exist. But, given the information to excite the standing wave, they do not build up over time. And, they have similar response dips which are normally spaced out at even intervals in the room's response. Most rooms, however, have some peaks and dips which are audible at average frequencies and they are present in almost all music. Pier and beam construction is more difficult to isolate from bass resonances since the floor acts as a sounding board. The PL equipment seems not to be too bothered by microphonics but it wouldn't hurt to experiment with some isolation devices. The clarity which comes with removing microphonic resonances is worth the effort in most cases. Isolation "cones" are normally not what you would use under a tube item. The PL amplifier might respond to such devices but normally tubes and source players are looking for something different. Try something soft like tennis balls cut in half and placed under your player. You might want to try the WASP set up method for your speakers. If the speakers are not set at equidistant locations relative to your listening position, you will never egt a top notch soundstage. http://www.tnt-audio.com/casse/waspe.html . , |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8847 Registered: May-04 | . If the bass actually "fades away" while you are listening, there is a problem for a technician to look at. If this happens with the DVD player in the system, you've indicated another unit would be the culprit. This, of course, applies only if the bass does fade away with the DVD player also. That could indicate a biasing problem in the amplifier. But, you've got to narrow this down by eliminating the possibility of one problem unit at a time. So, if the problem continues with the DVD player, you've got more troubleshooting to do. Standing waves are either there or they are not. That isn't quite true as it requires the frequency where the room has a null to excite the standing wave. Obviously, if the standing wave occurs at 38Hz and you never play music with information beneath 50Hz, the actual standing wave can't exist. But, given the information to excite the standing wave, they do not build up over time. And, they have similar response dips which are normally spaced out at even intervals in the room's response. Most rooms, however, have some peaks and dips which are audible at average frequencies and they are present in almost all music. Pier and beam construction is more difficult to isolate from bass resonances since the floor acts as a sounding board. The PL equipment seems not to be too bothered by microphonics but it wouldn't hurt to experiment with some isolation devices. The clarity which comes with removing microphonic resonances is worth the effort in most cases. Isolation "cones" are normally not what you would use under a tube item. The PL amplifier might respond to such devices but normally tubes and source players are looking for something different. Try something soft like tennis balls cut in half and placed under your player. You might want to try the WASP set up method for your speakers. If the speakers are not set at equidistant locations relative to your listening position, you will never get a top notch soundstage. http://www.tnt-audio.com/casse/waspe.html . , |
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Gold Member Username: John_aLondonU.K. Post Number: 4404 Registered: Dec-03 | "The PL equipment seems not to be too bothered by microphonics" I found a definite benefit of moving my PL2 away from between the speakers. I cannot resolve the amp in the photo. |
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Bronze Member Username: Philipt95148Post Number: 12 Registered: Jun-06 | Hi all, Just want to give you an update on this, having spent a week of setting up, listening, experimenting to give it full justice. Over the last weekend, a lot of times was spent with speakers set up and I think my room was the major culprit, it was very easy to upset the sound with just very minor moves. I am not there yet but probably less than an inch here and there to get the optimum site. The Apollo was put on isolation cones, I bought these in Europe so I don't remember what they are called anymore but they are fabricated in aluminum and consist of two pieces that sit on top of each other. I used reinforced 1 1/2 inch black PVC tubing, the type you connect washing machine waste output with, I cut 2 inches each and put them under the PL. I find that the pipe wall is strong enough to support the weight of the PL whilst providing good isolation. Results. Extremely good soundstage for orchestral pieces. Clear and sweet mid range for vocal, especially female. Violins and cellos sound gorgeous and real (to my ears), some piano notes are harsh. Bass is there but the jury is still out on this. I read the thread on the Apollo and found someone saying that it does not have the "toe tapping" bass quality. I can confer with that. John A was saying "the bass player is where he should be" and I would say that I don't doubt that, it is not the question where he is but why he does not join in the band and groovy. Is this the Apollo/the PL (Nuck -The PL is going to deliver smooth untainted sound without pushing the bass to the front of the stage) or the MA? I did mention that the Vienna Acoustics Beethoven has better bass extension but that is in a different league. I did not take the Apollo to a local dealer for a comparison for fear of "upgradenitis". For the moment I am happy with the sound. I will spend some more times with speaker positioning, isolation devices, tennis balls etc. to find the best sound out of the system. Once I get that and get used to it, then maybe it's fairer to compare to other components (and budget). At the moment though, I will leave you with this thought, maybe the Apollo and RS6 is not the best combination for bass? I do want to thank you all for the help and feedback, it has been a pleasurable journey of discovery and learning. Cheers |
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Gold Member Username: NuckPost Number: 3500 Registered: Dec-04 | Philip, you have a better notice of response than we can here online. Have you tried any bass traps in the corners? They may be unsightly, or may be considered baby-bouncers. This worked for a friend of mine. Cannot keep the kid away! Just a thought as you seem to have covered all the bases so far. |
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Gold Member Username: John_aLondonU.K. Post Number: 4434 Registered: Dec-03 | Thanks for the bulletin, Philip. I still think it likely that your system itself has a good, flat frequency response. If in doubt, you could get a Sound Pressure Level meter and a test disc. |
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Bronze Member Username: Philipt95148Post Number: 13 Registered: Jun-06 | Nuck, Can you give me an example of what bass traps look like? Is this similar to acoustic dampening? I have a question for the forum. The PL is rated as 35w, the RS6 starts at 40w. Am I underpowered here? I tend to listen mostly at low volume, the dial is never above 9pm mark, more like 7.30/8.30pm most of the time. I would appreciate your help. |
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Gold Member Username: NuckPost Number: 3557 Registered: Dec-04 | Philip, imagine a 7foot length of pipe wrap made to insulate a 12" air conditioner duct(round). |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8908 Registered: May-04 | . Traps can be several different shapes, sizes and varieties. This is a basic Tube Trap: http://www.acousticsciences.com/tubetrap.htm. The function of a bass trap is essentially the same as acoustic room dampening though the latter is more normally what you describe when you refer to treating surfaces for mid to high frequency attentuation. And, of course, attentuation is not the only sort of room treatment you might consider at those frequencies. When working with a room you normally apply either absorption, diffusion or reflection. There are other methods which can give good results but they are typically beyond the skills of the average consumer. There are more than enough articles in the "Accessories" section of the forum to help you get ideas for how, when and where to use the various forms of room treatments. . |
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Bronze Member Username: Philipt95148Post Number: 14 Registered: Jun-06 | Nuck/Jan, Thanks for the replies. So the amp wattage isn't an issue? |
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Gold Member Username: NuckPost Number: 3560 Registered: Dec-04 | Although the crossover in spec is out of range, we don't listen to specs. Jan's previous post as per tube/trans power was close enough regarding oscillation and perceived quality and power. A rather good transistor amp will deliver 100 watts as opposed to 35 equal watts of tube/valve. The difference being that there are only a few really good transistor amps out there as good. Not likely an issue. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8910 Registered: May-04 | . No. For the most part, if the amp and speakers sound good to you at the volume you prefer, then there probably isn't a problem. You should have some idea what the demands of your speakers are. Do they have an unusual impedance swing? Do they have a difficult electrical phase angle? If yes to either of these questions, you should know why the problem exists and just how much of a problem it represents. You should also have some familiarity with the amplifier you own and its ability to match electrically with your speakers. Tube amplifiers prefer certain electrical conditions in a loudspeaker and will work much better with some large, simply designed systems than they will a small, inefficient complex system. Yet one of the smallest, most inefficient speakers ever designed is also considered one of the most tube friendly designs ever created. The reasons for this matching can be found by reading the "Tube Talk" thread. Here's another example of bass traps and room treatments I just found. http://www.ethanwiner.com/acoustics.html . |
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Bronze Member Username: Philipt95148Post Number: 15 Registered: Jun-06 | Hi Jan/Nuck, Now I am confused! If the specs are not that important, what can we use it for? I could not find Jan's thread on this. Can you give me the link. Jan, you lost me on all those questions, I am afraid. Please excuse my ignorance but I only know the RS6 sensitivity of 91db. To my limited knowledge, this means the speakers are "easy" to drive. I have read the entire Tube talk threat, there is just soooo much info, I have to read it again to understand. |
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Bronze Member Username: Philipt95148Post Number: 16 Registered: Jun-06 | I found a definite benefit of moving my PL2 away from between the speakers - John A. John, What speakers do you use with your PL2. I might have seen your system in one of the threads somewhere but cannot remember. Do you match the specs in your selection? |
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Bronze Member Username: PointeOttawaCanada Post Number: 28 Registered: Jun-06 | I mentioned in some other threads about my bass traps. I built the exact ones described on the Ethan Winer site Jan quoted. The benefit was absolutely nothing short of astounding. It cost me about 150 bucks and was the greatest return on investment in my system. I made the modifications to my room because the home I moved from a month ago had a very nice room, accoustically speaking, just by my good luck. My new home has a rec room that is like a shoe box. My system was not failing miserably in the new conditions so I knew it was the room. The improvements have made the bass deeper, fuller and way clearer than I ever thought possible. I will be doing some additional tweaking to remove some tin-iness in the sound over the next month. Everyone should consider some level of accoustical treatment, although what I did may be too crude for most main-floor living rooms. |
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Bronze Member Username: PointeOttawaCanada Post Number: 29 Registered: Jun-06 | sorry: WAS failing miserably. how can I edit a post??? |
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Gold Member Username: NuckPost Number: 3579 Registered: Dec-04 | You just did, Geoff. I need to get the room fixed as well, and that same link has me shopping for the same materials, Geoff. The shop I've been to lately has tall corner stands of wrapped 12" pipe isulation in fibreglass,hollow, they seem to work pretty well(with Linn TT, Levinson amps and Dynaudio speaks). |
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Bronze Member Username: PointeOttawaCanada Post Number: 30 Registered: Jun-06 | just did what? "My system was not failing miserably" should read "was failing" my train of thought was interupted... so how do i edit a post? many thanks, and apologies if its obvious. |
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Gold Member Username: NuckPost Number: 3581 Registered: Dec-04 | You just edited, that is the only way to do so. Forum has no moderators or functions, you see. I am rather glad that your system is not 'failing miserably', only failing. As are many from time to time, depending on expectations. Your kit looks like a dandy from here. The room fixes seem to be very good as well. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8914 Registered: May-04 | . "Jan, you lost me on all those questions, I am afraid. Please excuse my ignorance but I only know the RS6 sensitivity of 91db. To my limited knowledge, this means the speakers are 'easy' to drive." What 91dB sensivity implies is the speaker will play at a higher SPL (it will sound louder) than a speaker with an efficiency spec of 88dB when both speakers are fed an identical voltage level. Typically the voltage used to measure sensitivity is about 2.83 volts which into a straight 8 Ohm load should produce 1 watt of electrical power. Are 91dB sensitive speakers easy to drive? Probably, but that spec alone doesn't tell you that. You should know how the speaker system operates. That takes into account the driver(s), the crossover type and crossover complexity and the enclosure type. I can't tell you everything you will need to know about speakers but these parameters will give you a good idea whether an amplifier and a speaker are a good match. Most importantly you should have some idea of the minimum and maximum impedance values your speaker presents to the amplifier. You should have some idea where these values occur in the frequency range of the speaker and hopefully what causes the impedance to drop and rise. The crossover and its complexity are often the most obvious cause for a speaker's impedance curve. You should have some idea of why the impedance is dropping and what that does to the eletrical phase of the speaker. A speaker with a degree of phase angle between 1° and 89° will be increasingly difficult for most amplifiers and typically more so for a tube amplifier due, in part, to the high-ish output impedance of transformer coupled amplifiers. Tube amplifiers typically do not deliver large amounts of current and you should consider a tube amplifier a voltage source. You can often consider a well designed and constructed soild state amplifier a current source. Most multidriver speaker systems will have a phase angle which falls between the 30° and 70\ch[deg} mark. This is a result of the number of inductors (including the driver's voice coil) and capacitors used in the speaker's crossover and how they sum to set the overall phase angle of the system. ****************************************** "For a perfect inductor, voltage drop always leads current by 90o, and so an inductor's impedance phase angle is said to be +90o. For a perfect capacitor, voltage drop always lags current by 90o, and so a capacitor's impedance phase angle is said to be -90o." (http://www.faqs.org/docs/electric/AC/AC_5.html) ********************************************** This degree of phase angle establishes whether the speaker can be considered a "resistive" or "reactive" load on the amplifier. A resistive load presents few problems to the amplifier while a reactive load will make demands which the amplifier might not be able to satisfy. The more resistive the load the more likely it will suit a tube amplifier no matter how efficient the speaker is. Reactive loads most often represent low impedance speaker systems which require large amounts of current flow to drive and control the system adequately. While it is a broad generalization to suggest the number of components in the crossover will be in part responsible for the load the amplifier sees, it is a reasonable place to begin. Simple (or no) crossovers can be a start to a speaker which works well with tube amplifiers. But, the manufacturer's specifications or a test bench measurement are what will truly determine whether the speaker is mostly resitive or mostly reactive. The same is true for your amplifier with a test bench telling you the most about an amplifier's ability to deal with difficult loads. Most test bench measurements, however, are static in nature and do not reflect the dymanic conditions an amplifier encounters while driving a loudspeaker. Do I expect you to understand all that and appply it to your system today? No. There are plenty of things about audio that I don't know and that I find out on a regular basis. It is a vicious cycle in that the more you know, the more likely you are to understand what you find. However, the more you know, the more you find you need to know. But, the dealer should be able to help you when you suggest a possible match. And, as you continue to read, you will discover the basics of what you should consider when you begin to match components. Be patient, pay attention and you will catch on. http://search.yahoo.com/bin/search?p=capacitors%20and%20inductors%20and%20phase% 20angle . |
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Gold Member Username: NuckPost Number: 3591 Registered: Dec-04 | Jan, at oscillation, how does the phase angle change, under uncontrolled power? Tubes handle and deliver oscillation in a more controlled manner(i think) as opposed to trans, and I have seen a few units that cannot handle any oscillation at all without running away and smoking. |
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Bronze Member Username: Philipt95148Post Number: 17 Registered: Jun-06 | Be patient, pay attention and you will catch on. I will try Jan. At the moment, I am getting a headache Thanks very much for your patience though, I really appreciate your detailed answers, always. |
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Gold Member Username: NuckPost Number: 3598 Registered: Dec-04 | You and me both, Philip! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8915 Registered: May-04 | . Sorry, Nuck, I don't know the answer to that one. I've not sat and watched an amplifier immolate itself. . |
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