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Is there a noticeably audible difference between two level matched solid state amps under controlled

  • Yes... I believe a notable difference can be heard.

    Votes: 136 48.6%
  • No... I do not believe there is any audibly significant difference.

    Votes: 144 51.4%

  • Total voters
    280
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Actually no it wouldn't at all. You can use almost any system or room you want provided that: #1. It stays exactly the same other than the change of amps. #2 The speakers and level used do not present a load that drives the amplifier into a range of non linear operation. ( No using electrostats at high volume with a cheap receiver guys.:nono:) #3 The amps are perfectly level matched. #4 The listener attempting to discern the differences cannot see or otherwise know which amp they are listening to at any time. #5 the amps shouldn't be intentionally color'd to begin with. Some amps are (tube amps, older rockford fosgate car amps, etc.)
The above is more or less a perfect selection for determining if there are any differences between amps :)
 

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Elite Shackster
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Actually no it wouldn't at all. You can use almost any system or room you want provided that: #1. It stays exactly the same other than the change of amps. #2 The speakers and level used do not present a load that drives the amplifier into a range of non linear operation. ( No using electrostats at high volume with a cheap receiver guys.:nono:) #3 The amps are perfectly level matched. #4 The listener attempting to discern the differences cannot see or otherwise know which amp they are listening to at any time. #5 the amps shouldn't be intentionally color'd to begin with. Some amps are (tube amps, older rockford fosgate car amps, etc.)
Which was kind of what this comment was aimed at:

That said, any room influence should be the same across all amps, and shouldnt be a factor, but removing it as a possibility would be the ideal.
 

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One thing to consider is that if there are multiple listeners, which will depend on the testing scenario, there may be bias in the listening position that might make some aspects of any potential differences more or less obvious, or provide distractors that might bias the result themselves. Distractors are variables that may not have any direct effect on what is being tested, but may affect the sensitivity of the test to detect differences or create a focus on some irrelevant detail that affects the attention of the listener.

For instance, suppose that there is a room effect that creates a null or boost at a certain frequency that annoys or simply catches the attention of a particular listener. After listening a bit, the listener might accomodate that difference and not notice it and be able to attend to the rest of the spectrum better. The result might be a conclusion that some difference exists that might not. Of course, multiple trials, random presentation, multiple levels, and other experimental techniques might be applied to minimize the effect of such problems. That takes careful experimental design, however, which may or may not be present.

The point is, room acoustics CAN be accounted for in experimental design but anytime you deal with such a variable that can introduce a bias or variablility you have to consider the implications for the design in terms of numbers of trials, randomizing conditions across subjects and trials, and the effect of the variablility on the ability to detect differences.
 

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Elite Shackster
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The anechoic chamber would be the best way forward, not because it would remove the room effects, but because it would remove the tendency to blame such possibilities for the end result, as in failing the test etc. While such a test would be possible in any room, removing any human elements (such as looking for blame in failure situations) would be the ideal IMO.

Thats really what I was trying to get at.
 

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One thing to consider is that if there are multiple listeners, which will depend on the testing scenario, there may be bias in the listening position that might make some aspects of any potential differences more or less obvious, or provide distractors that might bias the result themselves. Distractors are variables that may not have any direct effect on what is being tested, but may affect the sensitivity of the test to detect differences or create a focus on some irrelevant detail that affects the attention of the listener.
Doesn't matter. All of those factors are independent of the amp. If the amps sound the same then all of those factors will play out identically.

The one exception would be in an abnormally bad location and assuming that there *was* a difference. I don't think I could tell an overloading amp from a non-overloading amp if I'm standing next to a jet engine at the time.

The point is, room acoustics CAN be accounted for in experimental design but anytime you deal with such a variable that can introduce a bias or variablility you have to consider the implications for the design in terms of numbers of trials, randomizing conditions across subjects and trials, and the effect of the variablility on the ability to detect differences.
Multiple, blind, and random are certainly required. There can be no doubt.

The anechoic chamber would be the best way forward, not because it would remove the room effects, but because it would remove the tendency to blame such possibilities for the end result, as in failing the test etc. While such a test would be possible in any room, removing any human elements (such as looking for blame in failure situations) would be the ideal IMO.
I think they would just blame the anechoic chamber and argue that the amps make a difference that, when interacting with their room, is a huge deal.

The ideal scenario is to test in an area that the person claiming "I can hear the difference" has claimed to hear the difference.
 

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IMO, the ideal situation is good experimental design that eliminates as many variables as possible and controls for the rest. What either side argues as bias is not as relevant as using methodology and analysis that is good science and can be used to further knowlege regarding what is audible and under what conditions.

I agree that if one is trying to determine whether claims of being able to detect differences are accurate and one is trying to disprove those claims it make sense to use the conditions that satisfy the claimant. This, however, is not good science. Good science does not try to disprove the beliefs of some in favor of those of others. Good science extends knowledge in an area through experimental manipulation of variables and appropriate analysis of results. No good experimental design sets out to prove that there are no differences. One makes a hypothesis and fails to reject the null if there are no differences.
 

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I agree that if one is trying to determine whether claims of being able to detect differences are accurate and one is trying to disprove those claims it make sense to use the conditions that satisfy the claimant. This, however, is not good science. Good science does not try to disprove the beliefs of some in favor of those of others. Good science extends knowledge in an area through experimental manipulation of variables and appropriate analysis of results. No good experimental design sets out to prove that there are no differences. One makes a hypothesis and fails to reject the null if there are no differences.
So if one wants to determine how a wolf pack hunts: it would be bad science to observe a wolf pack hunting in the woods (as this would lack a manipulation of variables) and instead would stick individual wolves in empty rooms with (preferably artificial: as they are more consistent) prey ?!?

By removing the conditions under which people claim to hear differences, you may remove the actual cause of those differences. What if the amp causes the speakers to excite walls differently than another amp?

No. If you want to know if amps are different all you need is a meter.
If you want to know if differences are audible: you use headphones.

If you want to test the claim that people can hear differences: you do it in the setting that it has been claimed in.
 

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If you want to do good science you control for as many variables as you can and manipulate the one under test. If you hypothesize an effect due to room acoustics or the interaction with loudspeakers or whatever, you treat that as an experimental variable.

Observation is the start of all science. Some knowledge is gained from observation, some from experimentation. When you are testing a condition such as described here and trying to define the conditions under which differences may exist, it is entirely reasonable, actually expected, to control as many variables other than the one under test as possible. It may be reasonable to use a setting that is similar to that in which subjects who claim to hear a difference are accustomed, but the results may not be as conclusive as many would like to consider if sufficient controls are not in place. I explained above one example of how room acoustics could have an effect that is not controlled for. There are many considerations in any study and generalizing is difficult. One has to consider each on its own merits. The context of a specific experiment needs to be considered, along with the number of trials, source material, subjects, and all of the specific conditions.

If you simply want to determine whether a particular individual can tell the difference between two amps in a given system or not, then what you describe is fine. My point remains that there is much more to be learned from experiments that are more targetted to discovering what is audible and to what degree in more carefully controlled designs.
 

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It's still the same problem. You are watching a wolf in captivity and trying to add a tree and bird-call to get wild predation. In theory, theory is the same as practice; but is practice it isn't.

I assert that you are working backwards. You would first need to determine that a difference in experience exists and then attempt to determine the cause. If you don't all you are going to do is a thousand tests to end up right where I suggested you start and know nothing more than if you had skipped ahead.

Since you are interested in science (thought I'm not sure why): science is the process of creating models which can be used to make accurate predictions about reality. You want to execute a scientific experiment? Then describe your model and show how you are testing a falsifiable prediction. If you do not, then you are tossing around the term "science" rhetorically.

I'm interested in practical reality. It is less an issue of accurate models and more an issue of proving or disproving a claim of fact. As such: burden of proof falls on the positive claim. The positive claim is that a difference can be detected.

Better still is the claim that a difference *is* detected under some set of conditions.

Obviously: if a difference can be detected under some conditions, whether it can be detected under all conditions is not really important to establishing the presence of a difference. (obviously: we must remove non-auditory tester bias... all things must be the same except that which is being tested).

If you simply want to determine whether a particular individual can tell the difference between two amps in a given system or not, then what you describe is fine.
Isn't that exactly the claim being tested?!? It's the title of the thread.

Now if you found a difference and then wanted to understand *why*. THEN I would agree with your proposed methodology to isolate the cause.
 

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More precisely controlled experimental designs are desirable in my opionion. If you think otherwise that is your opinion and you are welcome to it. I don't care to batter the corpse any longer. I have made my point and you have a different view. So be it.
 

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Elite Shackster
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I think they would just blame the anechoic chamber and argue that the amps make a difference that, when interacting with their room, is a huge deal.

The ideal scenario is to test in an area that the person claiming "I can hear the difference" has claimed to hear the difference.
This is a good point, but with one caveat. You then have to decide if the room is the difference, or the amp, or a combination of both. This would require doing the test again and again in multiple rooms to iron out the issue of room interaction, human perception and amp variation. Its well documented how the 5 human senses are basically one sense, with each influential on the other, in scenarios far outside of what is seemingly logical, and that the human mind takes short cuts based on experience to define what it thinks should happen. The individual senses arent fooled, but the mind is, by its own choice.

This leaves one solution IMO. Remove external influencing factors as much as possible, and especially factors that will manipulate the genetically inbred human tendency to assume results. I would do the test in a controlled environment, and go so far as to blindfold the subject etc to remove the influence of or other senses on the test. There does come a point though, were your just going to extremes to try prove a point, and real world scenarios are more representative. Round and round we go.

IMO, the round and round we go result is a clear indication of an area that is being explored to simply try prove a point, when there probably is no need, and no point to really prove, in this case, proving you can hear there difference.
 

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I tried out a McIntosh first gen solid state amp in the '70s (after my brother repossessed it) and it was truly awful as I believe all first gen transistor amps did. In the '90s I thought a Sony basic stereo amp sounded better than an old Sherwood amp did. These days I don't think that there is a difference in sound between well designed amps with low distortion, certainly those with flat frequency, and low thd and IMd. Measurement of sound equipment has been going on for many decades and today a thorough objective test suite will show what is causing differences in sound. One might like different colorations, I certainly like some, but if the amp tests well it will be neutral.
 

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Concerning testing environment.
As long as the amp is the only item changed in the system, it doesn't matter what the environment is. If the sound between amps is different, it has to be the amp itself.
I do believe listening in a controlled environment would make it easier to hear a difference if there is one, because it would minimize outside distractions.
Wolves separated in captivity would act differently than a pack in the wild, but wolves and amps are completely different beasts. The amps have no idea where they are, and do not change their characteristics.
 

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You are correct. There is all sorts of non-sense that goes on but at the same time there are measurements that explain all sorts of real differences in sound. One of the problems is people often compare the difference in sound between an inexpensive (or even $2000 one) receiver and a separate power amp. Receivers almost always overstate (lie) their power output and distortion will be much higher because of an insufficient power supply. I therefore doubt that there is a sound to amplifiers that can't be explained through measurement. Perhaps there is but that is for someone with more "golden ears" (read golden pockets) than me. If so they should spend some time coming up with a measurement that quantifies this and not use the subjective "language" (without correlating the word with something that can be measured) that has been developed by those selling and reviewing the very high end.
 

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I've got to agree with Jerry on this one.

The room is not a variable. It must stay the same during the tests otherwise it becomes one. Anything that is acting equally on both DUT's is not a variable. That word indicates that there must be some sort of change happening which there would not be otherwise the entire test would be invalidated. On a side note I'd contend that listening to speakers in an anechoic chamber would be a much stranger condition and effect on the listeners perception of sound than any usual acoustics issues present in a much more normal, random, room environment, taking much longer to get acclimated to.

Sure...Ideally you'd want as accurate of a playback system with as wide of a bandwidth as possible and the best environment possible with the lowest noise floor and intimately familiar material to listen to, but all of that doesn't really relate to the real world.

Let's say that you stick big time music producer Rick Rubin who has spent many years critically listening to music and probably knows how to spot minute differences in the sound, in a huge anechoic chamber outfitted with the most neutral set of passive speakers somoeone like Genelec or JBL can engineer coupled with laboratory grade power supply and front end electronics. You lock him in there for a month listening to his music on both amps with them being switched randomly in between songs so he can get used to the system and chamber. Then you do another 14 days of the tests where he guesses which amplifier is on for each of 72 songs a day. We'll get MIT to run the whole deal. At the end of it compile the results. Lets say that he actually got a statistically significant, higher number of guesses right than just chance would suggest.

Does that prove that you can hear the difference in amplifiers? Should you start listening to them before buying to use in your room at home? Personally I'd say no. Others would say yes we have the proof..EAT IT LOSERS!:eek:lddude: Obviously there are real measurable differences between most amplifiers and the way I see it if a test happened like that it would prove conclusively one way or the other whether it is possible to tell the difference reliably with the human senses, but it wouldn't mean much in the real world of inferior: speakers, acoustics, listeners, noise floor, etc. Basically if a scenario like that is what it takes to be able to tell the difference conclusively, a percentage of the time, what chance would there be for Sonnie to do the same in his underground swamp fortress?:D What if Mr. Rubin with Uber system and MIT moderation failed to identify the amps reliably?
 

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OK, here is something for you to mull over. If a 'real world' room is the test room, and a participant does detect a difference, then in theory, changing the room to one with different effects should still yield the same result should it not. It might even be conceivable to say that the fairest test would be one that is replicated in a few different rooms. If the results vary, the room is to blame, and an anechoic chamber would then be the only logical test facility. Swapping the order of the test questions would further help resolve that issue.

So I ask, why even risk that variable, and not just rule the room out anyway. The fewer variables the better the test, is that not the preference of science.

There are other concerns too, what if you used a pair of 50$ speakers, would that be a fair test :D. Obviously it wouldnt, but what would such a test reveal about amps? I'm with you on this though Ricci, if that is the kind of test required to prove this, then the results probably show its something we really dont have to worry about, meaning that a no vote above would be technically incorrect, but in the real world, actually closer to the real world result truth.
 

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Discussion Starter #137
I don't see where the room is going to matter if everything is equal other than the amps being swapped out.
 

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I must say that for a Thread that could easily devolve into anarchy and personal attacks that this Thread has gone quite well. Props to all who have taken part.

While I have never heard massive differences in the Amplifiers I have Owned over the years, I do believe in having large Power Transformers and high levels of Capacitance. This is predicated by the Electrostatic Speakers I have been using for over a Decade. Using a 5.1 Electrostatic Surround setup has really made me grateful that I have powerful Amplifiers that are stable down to 2 Ohms.

Electrostats are simply Speakers that are quite demanding of Amplifiers. Not only do they drop below 1 Ohm in the upper registers, but they present a difficult Capacitive Phase Angle. With Sonnie's Prodigies, while little Musical Information is present where Electrostats present their lowest Ohm load, at around 8 khz where there is plenty of action the Ohm load is still 3.55 Ohms with a Capacitive Phase Angle of -58 degrees.

While there might not be great sonic differences between the Amplifiers I use, not all Amplifiers are capable of coping with the demands of Electrostatic Speakers. Interestingly, it is the highs that are rolled off when not using a sufficiently powerful Amplifier.
Cheers,
JJ
 

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Elite Shackster
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I don't see where the room is going to matter if everything is equal other than the amps being swapped out.
Then there should be no problems repeating the test results in several rooms, just to be sure, should there. If it was my 10k, I would be adding that into the mix as well. If I was taking the test, I would specifically ask for an anechoic chamber to try give myself the best chance of winning.
 
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