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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: 139 48.6%
  • No... I do not believe there is any audibly significant difference.

    Votes: 147 51.4%

Can we really hear a difference between amps?

179K views 835 replies 96 participants last post by  jonathonsmith 
#1 ·
Can we really hear a difference between two amps?

More specifically... between two amps that have been level matched in a controlled listening test. We are not talking about amps that have been modified or are driven beyond their reasonable limits.

What a crazy and completely worn out question... I know, I know, but I figured why not have a bit of fun with it anyway.

Naturally our ZERO TOLERANCE FORUM RULES are going to apply as they ALWAYS do! So... if you are one of those who simply cannot have a sensible discussion on a hot and debated topic... STAY FAR AWAY from this thread. :D

Consider the following link and quoted articles:

LINK: Science and Subjectivism in Audio

Any amplifier, regardless of topology, can be treated as a “black box” for the purpose of listening comparisons. If amplifiers A and B both have flat frequency response, low noise floor, reasonably low distortion, high input impedance, low output impedance, and are not clipped, they will be indistinguishable in sound at matched levels no matter what’s inside them. Of course, some of the new “alphabet soup” topologies do not necessarily satisfy those conditions.

I really believe that all this soul-searching, wondering, questioning, agonizing about amplifiers is basically unproductive and would be much more rewarding if applied to loudspeakers instead. For various reasons that I have discussed in the past, people are more willing to change amplifiers than loudspeakers. That’s most unfortunate because a new and better loudspeaker will change your audio life but a new amplifier will not.

—Peter Aczel, Editor & Publisher, The Audio Critic
There has been a lot of hot chatter on the E-mail circuit over the past couple of months about the Steve Maki and Steve Zipser challenge in Miami. I thought you would appreciate a complete recount of the events. Zipser, a high-end salon owner, had issued a challenge that he would pay the airplane fare of any interested party who wanted to see him prove he could hear the differences between amplifiers.

On Sunday afternoon, August 25th, Maki and I arrived at Zipser's house, which is also Sunshine Stereo. Maki brought his own control unit, a Yamaha AX-700 100-watt integrated amplifier for the challenge. In a straight 10-trial hard-wired comparison, Zipser was only able to identify correctly 3 times out of 10 whether the Yamaha unit or his pair of Pass Laboratories Aleph 1.2 monoblock 200-watt amplifiers was powering his Duntech Marquis speakers. A Pass Labs preamplifier, Zip's personal wiring, and a full Audio Alchemy CD playback system completed the playback chain. No device except the Yamaha integrated amplifier was ever placed in the system. Maki inserted one or the other amplifier into the system and covered them with a thin black cloth to hide identities. Zipser used his own playback material and had as long as he wanted to decide which unit was driving the speakers.

I had matched the playback levels of the amplifiers to within 0.1 dB at 1 kHz, using the Yamaha balance and volume controls. Playback levels were adjusted with the system preamplifier by Zipser. I also determined that the two devices had frequency response differences of 0.4 dB at 16 kHz, but both were perfectly flat from 20 Hz to 8 kHz. In addition to me, Zipser, and Maki, one of Zip's friends, his wife, and another person unknown to me were sometimes in the room during the test, but no one was disruptive and conditions were perfectly quiet.

As far as I was concerned, the test was over. However, Zipser complained that he had stayed out late the night before and this reduced his sensitivity. At dinner, purchased by Zipser, we offered to give him another chance on Monday morning before our flight back North. On Monday at 9 a.m., I installed an ABX comparator in the system, complete with baling-wire lead to the Yamaha. Zipser improved his score to 5 out of 10. However, my switchpad did develop a hang-up problem, meaning that occasionally one had to verify the amplifier in the circuit with a visual confirmation of an LED. Zipser has claimed he scored better prior to the problem, but in fact he only scored 4 out of 6 before any difficulties occurred.

His wife also conducted a 16-trial ABX comparison, using a 30-second phrase of a particular CD for all the trials. In this sequence I sat next to her at the main listening position and performed all the amplifier switching functions according to her verbal commands. She scored 9 out of 16 correct. Later another of Zip's friends scored 4 out of 10 correct. All listening was done with single listeners.

In sum, no matter what you may have heard elsewhere, audio store owner Steve Zipser was unable to tell reliably, based on sound alone, when his $14,000 pair of class A monoblock amplifiers was replaced by a ten-year old Japanese integrated amplifier in his personal reference system, in his own listening room, using program material selected personally by him as being especially revealing of differences. He failed the test under hardwired no-switching conditions, as well as with a high-resolution fast-comparison switching mode. As I have said before, when the answers aren't shared in advance, "Amps Is Amps" even for the Goldenest of Ears.

Tom Nousaine
Cary, IL
Richard Clark $10,000 Amplifier Challenge FAQ

by Tom Morrow

Written 6/2006


The Richard Clark Amp Challenge is a listening test intended to show that as long as a modern audio amplifier is operated within its linear range (below clipping), the differences between amps are inaudible to the human ear. Because thousands of people have taken the test, the test is significant to the audiophile debate over audibility of amplifier differences. This document was written to summarize what the test is, and answer common questions about the test. Richard Clark was not involved in writing this document.

The challenge


Richard Clark is an audio professional. Like many audiophiles, he originally believed the magazines and marketing materials that different amplifier topologies and components colored the sound in unique, clearly audible ways. He later did experiments to quantify and qualify these effects, and was surprised to find them inaudible when volume and other factors were matched.

His challenge is an offer of $10,000 of his own money to anyone who could identify which of two amplifiers was which, by listening only, under a set of rules that he conceived to make sure they both measure “good enough” and are set up the same. Reports are that thousands of people have taken the test, and none has passed the test. Nobody has been able to show an audible difference between two amps under the test rules.
This article will attempt to summarize the important rules and ramifications of the test, but for clarity and brevity some uncontroversial, obvious, or inconsequential rules are left out of this article. The full rules, from which much of this article was derived, are available here and a collection of Richard's comments are available here.

Testing procedure


The testing uses an ABX test device where the listener can switch between hearing amplifier A, amplifier B, and a randomly generated amplifier X which is either A or B. The listener's job is to decide whether source X sounds like A or B. The listener inputs their guess into a computerized scoring system, and they go on to the next identification. The listener can control the volume, within the linear (non-clipped) range of the amps. The listener has full control over the CD player as well. The listener can take as long as they want to switch back and forth between A, B, and X at will.

Passing the test requires two sets of 12 correct identifications, for a total of 24 correct identifications. To speed things up, a preliminary round of 8 identifications, sometimes done without levels or other parameters perfectly matched, is a prerequisite.

Richard Clark normally has CD source, amplifiers, high quality home audio speakers, and listening environment set up in advance. But if the listener requests, they can substitute whatever source, source material, amplifiers, speakers (even headphones), and listening environment they prefer, within stipulated practical limits. The source material must be commercially available music, not test signals. Richard Clark stipulates that the amplifiers must be brand name, standard production, linear voltage amplifiers, and they must not fail (e.g. thermal shutdown) during the test.

Amplifier requirements


The amplifiers in the test must be operated within their linear power capacity. Power capacity is defined as clipping or 2% THD 20Hz to 10kHz, whichever is less. This means that if one amplifier has more power (Watts) than the other, the amplifiers will be judged within the power range of the least powerful amplifier.

The levels of both left and right channels will be adjusted to match to within .05 dB. Polarity of connections must be maintained so that the signal is not inverted. Left and Right cannot be reversed. Neither amplifier can exhibit excessive noise. Channel separation of the amps must be at least 30 dB from 20Hz to 20kHz.

All signal processing circuitry (e.g. bass boost, filters) must be turned off, and if the amplifier still exhibits nonlinear frequency response, an equalizer will be set by Richard Clark and inserted inline with one of the amps so that they both exhibit identical frequency response. The listener can choose which amplifier gets the equalizer.


FAQs:


How many people have taken the challenge?

Richard Clark says over a couple thousand people have taken the test, and nobody has passed. He used to do the test for large groups of people at various audio seminars, and didn't charge individuals to do the test, which accounted for the vast majority of the people who did the test. Around 1996 was the last of the big tests, and since then he has done the test for small numbers of people on request, for a charge ($200 for unaffiliated individuals, $500 for people representing companies).

When did the challenge start?


Sometime around the year 1990. Richard Clark says in a post on 7/2004 that the test with the $10,000 prize started about 15 years ago.

What were the results of the test?


Nobody has ever successfully passed the test. Richard Clark says that generally the number of correct responses was about the same as the number of incorrect responses, which would be consistent with random guessing. He says in large groups he never observed variation more than 51/49%, but for smaller groups it might vary as much as 60/40%. He doesn't keep detailed logs of the responses because he said they always show random responses.

Is two sets of 12 correct responses a stringent requirement?


Yes. Richard Clark intentionally made the requirements strict because with thousands of people taking the test, even random guessing would eventually cause someone to pass the test if the bar was set low. Since he is offering his own $10,000 to anyone who will pass the test, he wants to protect against the possibility of losing it to random guessing.

However, if the listener is willing to put up their own money for the test as a bet, he will lower the requirements from 12 correct down to as low as 6 correct.

Richard Clark has said “22 out of 24 would be statistically significant. In fact it would prove that the results were audible. Any AVERAGE score more than 65% would do so. But no one has even done that”.”

Do most commercially available amplifiers qualify for this test, even tube amplifiers and class D amplifiers?


Yes. Nearly all currently available amplifiers have specs better than what are required for the test. Tube amplifiers generally qualify, as do full range class D amplifiers. It is not clear whether Richard Clark would allow sub amplifiers with a limited frequency response.

Besides taking Richard Clark's word, how can the results of the test be verified?


Many car audio professionals have taken the test and/or witnessed the test being taken in audio seminars, so there isn't much doubt that the test actually existed and was taken by many people. One respected professional who has taken and witnessed the test is Mark Eldridge. Because the test has been discussed widely on audio internet forums, if there were people who passed the test it seems likely that we would have heard about it. Sometimes there are reports of people who believe they passed the test, but upon further examination it turns out that they only passed the preliminary round of 8 tests, where levels were not matched as closely as for the final test.

How can audio consumers use the results of this test?


When purchasing an amplifier, they can ignore the subjective sound quality claims of marketers. Many amplifier marketers will claim or imply that their amplifiers have some special topology, materials, or magic that makes the sound clearly superior to other amps at all volume levels. Many consumers pay several times more than they otherwise would for that intangible sound quality they think they are getting. This test indicates that the main determinant of sound quality is the amount of power the amplifier can deliver. When played at 150W, an expensive 100W measured amplifier will clip and sound worse than a cheap 200W measured amp.

Does this mean all amps sound the same in a normal install?


No. Richard Clark is very careful to say that amps usually do not sound the same in the real world. The gain setting of an amplifier can make huge differences in how an amplifier sounds, as can details like how crossovers or other filters are set. When played very loud (into clipping), the amplifier with more power will generally sound better than a lower powered amp.

Most people perceive slight differences in amplitude as quality differences rather than loudness. The louder component sounds “faster, more detailed, more full”, not just louder. This perceptual phenomenon is responsible for many people thinking they liked the sound of a component when really they just liked the way it was set up.

I changed amps in my system to another one with the same measured power and I hear a sound quality difference. Does this show that the test results are invalid?


No. Installing a new amplifier involves setting the gains and crossovers, and any slight change you make to those settings is going to affect how things sound.

Is adding an equalizer just a way of “dumbing down” the better amplifier ?


Richard Clark allows the equalizer to be added to whichever amplifier the listener wants. It can be added to the amplifier that the listener perceives as the weaker amplifier . The EQ is most likely to be used when comparing a tube amplifier (which exhibits slight high frequency rolloff) to a solid state amplifier . In that case Richard Clark says he can usually fashion an equalizer out of just a resistor and/or capacitor which for just a few dollars makes the solid state amplifier exhibit the same rolloff as the tube amplifier, and therefore sound the same. If the tube amplifier really sounded better, then modifying the solid state amplifier to sound indistinguishable from it for a few bucks should be a great improvement.

How might allowing clipping in the test affect the results?


It's impossible to know for sure because that would be a different test that has not been done. But Richard Clark seems to think that in clipping, conventional amplifiers would sound about the same, and tube amplifiers would sound different from solid state amplifiers.

Richard Clark reported that he did some preliminary experiments to determine how clipping sounds on different amplifiers . He recorded the amplifier output using special equipment at clipping, 12db over clipping, 18db over clipping, and 24db over clipping. Then he normalized the levels and listened. His perception was that with the same amount of overdrive, the conventional amplifiers sounded the same. With the same amount of overdrive the tube amplifiers sounded worse than the conventional amplifiers . On the basis of that experiment, he said “I believe I am willing to modify my amplifier challenge to allow any amount of clipping as long as the amplifiers have power ratings (actual not advertised) within 10% of each other. This would have to exclude tube amplifiers as they seem to sound much worse and it is obvious”.

If a manufacturer reports false power ratings, will that interfere with the test?


No. The test is based on measured power, not rated power .

Does this mean that there is no audible difference between sources, or between speakers?


No. There are listening tests that show small but significant differences among some sources (for instance early CD players versus modern CD players). And speakers typically have 25% or more harmonic distortion. Most everyone agrees that differences among speakers are audible.

Does the phrase "a watt is a watt" convey what this test is about?


Not quite but close. Richard Clark has stated that some amplifiers (such as tubes) have nonlinear frequency response, so a watt from them would not be the same as a watt from an amplifier with flat frequency response.

Do the results indicate I should buy the cheapest amp?


No. You should buy the best amplifier for your purpose. Some of the factors to consider are: reliability, build quality, cooling performance, flexibility, quality of mechanical connections, reputation of manufacturer, special features, size, weight, aesthetics, and cost. Buying the cheapest amplifier will likely get you an unreliable amplifier that is difficult to use and might not have the needed features. The only factor that this test indicates you can ignore is sound quality below clipping.

If you have a choice between a well built reliable low cost amp, and an expensive amplifier that isn't reliable but has a better reputation for sound quality, it can be inferred from this test that you would get more sound for your money by choosing the former.

Do home audio amps qualify for the test?


Yes. In the 2005 version of the test rules, Richard explicitly allows 120V amplifiers in a note at the end.

How can people take the test?


They should contact Richard Clark for the details. As of 2006 Richard Clark is reported to not have a public email account, and David Navone handles technical inquiries for him. Most likely they will need to pay a testing fee and get themselves to his east coast facility.

Is this test still ongoing?


As of early 2006 , there have not been any recent reports of people taking the test, but it appears to still be open to people who take the initiative to get tested.

Do the results prove inaudibility of amplifier differences below clipping?


It's impossible to scientifically prove the lack of something. You cannot prove that there is no Bigfoot monster, because no matter how hard you look, it is always possible that Bigfoot is in the place you didn't look. Similarly, there could always be a amplifier combination or listener for which the test would show an audible difference. So from a scientific point of view, the word “prove” should not be used in reference to the results of this test.

What the test does do is give a degree of certainty that such an audible difference does not exist.

What do people who disagree with the test say?


Some objections that have been raised about the test:

  • Richard Clark has a strong opinion on this issue and therefore might bias his reports.
  • In the real world people use amps in the clipping zone, and the test does not cover that situation.
  • Some audible artifacts are undetectable individually, but when combined with other artifacts they may become audible as a whole. For instance cutting a single graphic EQ level by one db may not be audible, but cutting lots of different EQ levels by the same amount may be audible. Maybe the amps have defects that are only audible when combined with the defects from a particular source, speaker, or system.
  • Some listeners feel that they can't relax enough to notice subtle differences when they have to make a large number of choices such as in this test.
  • There is a lack of organized results. Richard Clark only reports his general impressions of the results, but did not keep track of all the scores. He does not know exactly how many people have taken the test, or how many of the people scored “better than average”.
  • If someone scored significantly better than average, which might mean that they heard audible differences, it is not clear whether Richard Clark followed up and repeated the test enough times with them to verify that the score was not statistically significant.
Is there one sentence that can describe what the test is designed to show?

When compared evenly, the sonic differences between amplifiers operated below clipping are below the audible threshold of human hearing.

Links


Note from the author

I wrote this Summary/FAQ because I found that many of the people who disagreed with Richard Clark about the challenge simply didn't have the whole story on the challenge. I originally thought the challenge was flawed even after I read the rules a few times, but after reading lots of comments from Richard Clark, my objections were answered and now I believe that understanding the challenge is a very useful tool for learning what is audible and what isn't. I have no relationship with Richard Clark and have never communicated with him except that I've read his public postings about the challenge. If anyone finds typos or factual errors in this document please contact me.
I have leaned towards the camp of not being able to hear any significant difference between almost any two amps out there when played at moderate levels on the typical speaker system, unless there is something wrong with one or the other amp that might cause it to color the sound.

Granted... a low-end receiver may well have an issue driving a system of certain electrostatic speakers... or speakers with low sensitivity, especially if pushed to higher levels. There are going to be exceptions, but for the sake of this discussion, let's say we are using a pair of Klipsch RF-62 II speakers with a sensitivity of 97dB @ 2.83V / 1m ... or perhaps the Duntech Marquis speakers that Zipser was using above at 92db.

I have owned processor/amp combos and/or receivers from Sony, Denon, Sunfire, McIntosh, Adcom, NAD, Onkyo, Earthquake, Anthem, Rotel, Lexicon, Emotiva (and probably others I cannot remember) powering Snell B-Minors, Klipsh Forte, PSB Image, SVS, JBL, Boston Acoustics, VMPS RM30's, MartinLogan Ascents, ML Spires and recently the older ML Prodigy mains with a Theater center and Ascent surrounds powered by Emotiva XPA-1's and an Onkyo 906 Receiver. Currently (updated January 2104) I run an Onkyo 5509 with an Emotiva XPR-5 with MartinLogan Montis, Stage X and Motion 12's. The most significant difference I ever heard was moving to the Martin Logan speakers. NOTHING had EVER made anywhere close to a difference in sound as did the MartinLogan speakers. I thought at one time that my NAD receiver had more of a soft sound (maybe "warmer" as some will state the description), but was told (never did verify it with NAD or via measurements) that NAD intentionally setup their receivers with a rolled off high-end. However, I have heard significant differences in speakers. I have also performed A/B testing between several amps and have not found any differences outside of clipping and/or distortion.

Is it not the desire of the audiophile to have electronic equipment which does not alter the sound?

Your thoughts and comments will be interesting.
 
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#242 ·
You know that is a good point but I personally do not believe in DBT. It just is not how our brains work. There is a reason that most people are said to do no better than chance.

The human brain is not good in that type of situation, look at trying to remember names, directions, exact colors, numbers, grandkids names (JK). Human brains are pretty good visually, it remembers faces, photos, parts of movies, locations etc, but can be easily tricked there on occasion as well. This is one reasons that witnesses to a crime are not as reliable as once thought.

We have to live with something for awhile in order to drink in all the nuances. Can you imagine getting married based on a double blind Date ? Or buying a house based on a quick inspection without getting into the meat of it...a car, now we even get a 30 day evaluation on many audio components because even the manufacturers admit any given item, inclusive of amplification, may nor work for any given user.

I have heard differences in amps, some interconnects and cables, pre amps, DACs etc and I know this as a fact. There can be no way to convince me otherwise.
 
#246 ·
I am not trying to convince you that you cannot hear a difference but what you just described regarding how our brains work actually further solidifies the argument for DBT as the only way to prove if we actually heard a difference or not.

I completely agree that our brains have a very poor memory for very slight differences or to put it into audio terms very small nuances in a music track. I am not saying we cannot hear them when they are happening I am saying that our recall of that sound is just not that great. Thus, if you listen to some gear at one point in time and then go listen to that same gear again at a later date our memory of how that exact same gear sounds can even be very hard if not impossible to recall.

So the only way you can truly make a comparison between two amps is to listen to them at as close to the same time as possible under the exact same conditions - room, speakers, source material, source components, level matched and have no preconceived bias take part in that comparison (blind). Otherwise any other comparison at all is fairly useless. Even if you are very familiar with your room, speakers, source material, source components and your conduct the test your own bias will play too large a role to make a valid comparison and everyone has it. Bias that is.

I have participated in enough of these tests and sold more than my share of gear to understand how people purchase. First off, if you bring something home you are more likely to keep it in the end than if you just audition in the store and walk away. If you have to pack it and ship it back at your own expense you are even less likely to send it back. What you are told (or the research you do) about that gear will always play a huge role in how you perceive that gear to sound and perform. There is a reason hi-end shops have separate listening rooms with gear separated by price and/or brand. Some shops will let you mix and match to a limited degree for comparison purposes but in the case of amplification just try to haul one of their low end integrated amps or better yet a higher end AVR into the "salon" and wire it up to their flagship speakers. Even if the AVR has sufficient power to drive them to reasonable levels in almost all cases they will never let you do that let alone connect up an ABX switch between the AVR and their $50K/pair mono blocks. :)

This is why a GTG setting up a fairly reasonable DBT can be invaluable to someone who has never participated in such an event. Most of these have been with speakers and subs though which can be almost impossible to properly conduct. It is hard to hide the physical aspects of the speakers themselves and proper setup and calibration can be very time consuming. Amp or source component comparisons can be done much more easily as they equipment is easy to hide and the setup and calibration is very simple.

Maybe HTS or an ambitious member would volunteer to host one of these GTG's. Invite someone with credibility in the industry to oversee the setup and conduct the testing. Call it the ultimate HTS amplifier shootout.
 
#243 ·
It is how my brain works for comparing amps. My brain works different ways depending on the situation. No doubt everyone's brain works differently. I would need a DBT for this to be proven to me... plain and simple. I do not trust my brain in this situation (nor a lot of others for that matter). A DBT would be the ONLY way I could be convinced without any doubt I was hearing a difference. I am willing to submit to one to see if it were possible to hear a difference... I am certainly not going to avoid it because of fear I might change my mind. But hey... to each his own. You believe you can hear a difference and you don't want anything to take that away from you... you don't want anything to change your mind... so you'll have to take back that statement about being open-minded. :bigsmile:

As far as comparing DBT of amps to DBT of getting married. :rofl: That was just too funny. :rofl2:
 
#244 ·
Yeah I figured the marriage part would stick out for some of us.
I am sorry I gave the wrong impression about me, I really am open minded, but, and as we know everyone has a big but, I truly am willing to listen to some type of realistic test to bring my mind to rest about these issues. No body wants to be wrong really but for me this is not a life and death situation and as such there is no fear there. I absolutely love knowledge, truth and the American Way although I cannot jump tall buildings in a single bound.....yet :whistling:

What bothers me about the DBT also is that is seems to be so definitive, no one has been reported as coming away defeating it if we are to believe the reports. This to me seems totally against the odds and as such there may be something the matter with the test that removes the possibility of success, the $ 10,000 prize so willingly offered seems to raise a red flag for me.

Like you I also am a fan of Emotiva XPA amps and own them, along with a couple Emo subs, a couple Velodyne subs, Martin Logan speakers and a zillion other things that are at the same time fun and frustrating to play with. Tube Dac or SS Dac, iTunes or JRiver Media, Mac or PC, lions and tigers and bears oh my.

I suppose there will be a need one day to get into a comparison again, just to see if the tuned ears are still in tune eh ???

Note: One thing I am pondering is an IB sub, for that I doubt that amplifier differences will mean much as long as they have the power and quality to so the job for many years, I doubt I will be so picky. Getting myself to do this may be the biggest of problems but with the new house comes a dedicated room and huge space below. Hmmmmmmm.
 
#245 ·
The DBT is the only meaningful way to subjectively evaluate sound whether it be amps, speakers, wires, or sources.
Not believing in the DBT does not change that it is legitimate.
In DBT the listener does not even know if "A" is always the same component being switched in/out, the tester may give the option "A" / "B" where A and B are the same component.
To argue against the method being valid is pure audiophile baloney.
 
#247 ·
I am not sure how a DBT removes the possibility of success in hearing a difference, UNLESS there is no difference. I am not aware of anyone who has proven any fault with the DBT test methods that have proven no differences can be heard. I really wish more DBT would be done, so that if there is a difference, we could know without a doubt there is a difference.

I have to rationalize the best I can here. If I am unable to hear a difference in my home, then I certainly am not going to spend thousands upon thousands more because someone else says there is a difference. I would want definitive prove that there is a significant improvement (to my ears) in the sound... like what I heard when I changed speakers.
 
#249 ·
I will go so far as to say that two amps cannot be reliably distinguished from each other in a DBT.
That does not mean correctly identifying brand XX or brand YY, that means reliably identifying a difference in sound between the two.
When any one of the two are switched between themselves there will be equal guessing that the switch is between brand XX and brand YY as there is when the components are actually switched.

Processors may sound different since there is "processing" taking place, amplifiers and wires do not process the sound. Hence they sound the same.
 
#250 ·
I am reviewing a Denon 4520 right now and plan to connect the amps of that receiver to my MartinLogan setup. Although my ML's are rated at 4 ohms, the upper end is as low as 1 ohm, so I cannot say that the 4520 is necessarily the proper choice to drive the ML's, yet I do not expect I will notice a difference, unless maybe I am trying to hit 125db SPL in the room... perhaps the 4520 will run out of steam. Then again, maybe not, because I plan to bi-amp the mains, which are the ones that present the most difficult load. The thing is at normal listening levels I don't think I will notice a difference in the sound, although I will admit there may be a difference. I don't and won't know for absolutely sure because I have no valid way of testing it. The only way I could know for sure is to conduct a DBT between the two.
 
#253 ·
I think we live in the real world and not a DBT world, although I could be wrong on that since I have yet to find a life instruction booklet. Anyhow, here is a neat snip taken from the Clark test.

Does this mean all amps sound the same in a normal install?

No. Richard Clark is very careful to say that amps usually do not sound the same in the real world.



BUMMER. But next we may have to discuss the differences between Coke and Pepsi...if there are any....
 
#254 ·
But if you include the rest of the answer "The gain setting of an amplifier can make huge differences in how an amplifier sounds, as can details like how crossovers or other filters are set. When played very loud (into clipping), the amplifier with more power will generally sound better than a lower powered amp." It makes sense. In the real world when swapping out components users tend to not level match or keep all other settings the same. And we all agree that driving an amp into clipping will sound different.

I think what he is trying to say is under a true controlled DBT test there are no differences. But when people try to compare them on their own the don't control all of the variables and therefore they do not sound the same.
 
#256 ·
No the DBT does not happen in the real world, in the real world we listen to the system and do not add filters, adjust crossovers to make the amplifiers all appear to be the same. In the real world we hook em up and play.
A real world test would be to use the same system one always uses and insert the amps with no messing around. This will tell us what an amp, in a real world system will sound like. His definition is way to shallow, in that yes they sound different, unless we make them the same which he does by setting rules to ensure everything is well controlled. We do not base our decisions on that, we know what equipment we use and make a purchase on that point, we don't buy and amp and then try to correct everything else in the system to make the amp sound right.

If and note I say if, all amps sounded the same, there would be no reason to even listen at the store, just get one that seems to have enough power and go home. We could all save thousands I am sure. But that is not the case, even the naysayers have quite high end gear, now why would they do that if they can prove a cheap Pioneer sounds the same as a multibuck tube amp ?? The facts of what these guys actually do with their money tends to make their test look a bit silly.
 
#257 ·
No the DBT does not happen in the real world
That's odd; because I've participated in several and I'm pretty sure I am a real-world creature.

in the real world we listen to the system and do not add filters, adjust crossovers to make the amplifiers all appear to be the same.
What are you talking about? A DBT amp test only requires that the amps be level matched (you know; by turning that volume knob-thing until they are putting out the same volume?) and then some way to switch between them.

I have no idea what you are talking about with filters and crossovers and such. Perhaps that's the part that's in the fantasy world you were discussing.

If and note I say if, all amps sounded the same, there would be no reason to even listen at the store, just get one that seems to have enough power and go home. We could all save thousands I am sure.
I couldn't save much because that's exactly how I buy amps these days. Mind you I prefer the Yamaha over the Crown (when I don't need <4ohms) because the Crown has gaudy lighting; and I'd prefer a modern McIntosh over my Yamahas because 1) it's much prettier and 2) it can be turned on by remote/12v without having to resort to switched outlets.

I've had Krell and McIntosh and a few others: but most of my gear (that's not powered by the AVR) is running off Yammy P-series amps right now. If I were to add an external amp to the bedroom it would likely be an Emotiva (because of the appearance and 12v trigger).

And I've listened to the exact same speakers on multi-thousand dollar amps and my couple-hundred-dollar amps. No audible difference.
 
#258 · (Edited)
I do not have Super Golden Ears, but I believe they are Pretty Good Ears. There have been numerous times I thought I heard something - a change in my system, a difference between components that should sound the same, whatever - the next step for me was always curiosity, "OK, what is going on here, is this real? Is the apparent change/difference reproducible, maybe even explainable? Am I imagining this somehow?" Why? So I can avoid making changes or spending money unnecessarily, or - even worse - sending someone else on a wild goose chase based on an error.

So an investigation always follows. Once I discovered that one side of a graphic EQ had gone bad, was running essentially bypassed - good catch. Once I discovered that a budget power amp with good paper specs could run loud for awhile sounding fine, then distort audibly during a quiet passage while it cooled - another good catch. Many other times I thought I heard something, looked into it, ended up humbled at having to admit I had imagined it, Pretty Good Ears and all. All those other experiences showed me how unreliable auditory memory can be.

I fully respect that there are those who simply want to believe they hear something and care nothing about proof or validation. For audio gear decisions made in a vacuum, it is fine to make those choices without validation. When it starts to affect other people - their money, their time or trouble, then it seems the kinder approach to be able to validate the choice. My experience convinces me that in probably 99% of DBT-unverified "I hear a difference" instances, for power amps, cables, etc, under the conditions of proper design & use as previously discussed, the difference is imagined. The other one percent? Super Golden Ears &/or ESP.

I want to believe there are Super Golden Ears out there who can hear the difference between amplifiers. It gives me something to aspire to. If I ever claim to have reached Super Golden Ears status, I will expect to be able to back it up reliably through DBT so I can be confident I am really hearing it. That way, I can tell someone "A sounds better than B" with confidence that it really does. If I never intend to communicate unvalidated findings, then it doesn't matter.
 
#259 ·
Its been my experience that the people that believe that there is an "audible difference" in amps that are on the same ground meaning that they are well made and of the same design not Tube or ICE or magnetic field for example are the same people who believe that spending ridiculous amounts of money on interconnects or power cables will make an audible difference.
Ive found that when someone spends alot of money and then has to justify it or it makes them feel good it has little to do with what they hear but more just a feeling. If you think you hear a difference the more power to you but in all reality and in actual tests this should not be the case if the manufacturers build to correct specifications.
 
#261 ·
Very good, there really is not much else to say without sounding argumentative and that was not my purpose. It would appear that a tad less than 50% of the folks that answered the poll believe we really hear a difference between amps and a tad more than 50% believe we cannot really hear a difference between amps.

It seems odd that the tad more than 50% wish to push their beliefs harder than the tad less than 50% albeit some of those like Terry J have done so with style and grace. I am not in any way special, quite the contrary, I just have spent many years listening, and listening and listening. As alluded to earlier, I have not been involved in blind tests, although I have attended countless component swaps during extended listening tests, nor do I know anyone that has. (Personally I mean)

Admittedly I will admit to not being the most logical in the bunch as my thought process tends more toward right brain activities and may explain my findings more than my words. I cannot prove what I have heard and frankly I do not know that proof exists any greater than I can prove my dislike of liver. I can describe what I hear in the same way I can describe how awful liver tastes, but that would not be considered proof in the scientific community.

Oh and I truly would be up to hearing proof that contradicts my belief, as I said before, this is not life or death and it would give me the chance to learn new things that even this old dog needs on occasion.

So lets just agree to disagree, I do not wish to disrespect this forum nor those in it by typing anything else that may cause further disruptive dialogue from the ahem....Matrix.
 
#263 ·
Thankyou for the reasoned response, all too often these things go pear shaped if you know what i mean!

You prob do not even realise it, but you are still having a bob both ways. You say proudly (and seriously, good on you..as I said I think it is rare) that you'd be happy to have your beliefs pushed, esp if it were in sake of learning.

So as THAT stands, the follow on should be something like.."I must get a tad serious about doing a test like this, nothing that might pass scientific curiosity but maybe I'll just get the wife to swap the leads and not tell me which is which'..you know, just a gentle step in that direction if your stated stance was to be believed.

Instead, we get in the very next sentence...'let's just agree to disagree'.

So which IS it? A genuine desire to learn (based on an admission you know nothing really about the way these tests are done, have never organised nor participated in one, finally agreed that you are just as vulnerable to bias and suggestion as the rest of us) yet then 'let's just disagree' (in other words I have no proof one way or the other but hey I reckon you are wrong yet will not test it).

Sorry if it looks like I picking on you, not really. But you are bringing up good points to respond to!!

As an example, you got a bit huffy when I pushed the point that you, and people like you, actually know extremely little about how much we can be affected by bias and suggestion (not even that we can be affected, but by how much. Eg, "ok I accept we have biases, but I don't accept that I would start hearing things I have never heard before simply based on suggestion"...is there a bit of truth in that for you??? Anways, when I say 'you people have no idea'' that is the area I am heading towards..because you CAN hear all these marvellous things you have never heard before, even if like dunlavy no cable was changed at all. It is simply stunning what we can 'hear or not hear' solely due to our beliefs. Ask ANY pro audio engineer about the silent channel, it does nothing yet allows the band member to tweak any aspect of the sound to his satisfaction. And he does. He hears the change and is now happy yet it was never connected in the first place. The mind is a fascinating animal)

hmm, that got a bit off track, sorry. But we were talking about good points of yours to address. Earlier you said dbt's and our minds don't work that way. 'We need time to adjust and hear it, we don't marry someone on the basis of a blind date'

The first and obvious rebuttal is that no where in a dbt is mention of a time limit. You can, if you wish, take a month before you switch. Still, I am not interested in that road but rather the following.

This fatal flaw you mention of dbt's and how long we need to live with a component, can you link me to a post of yours where you explained that you chose your amp after needing a month to get a handle on it? Can I ask you straight up, what worth do YOU put on an amp such that it takes a month before you are comfortable with it sounding different from the one it will replace?

Personally, I would not spend ten bucks if it took a month to hear the differences. Yet that is a flaw of dbts?

One point you have yet to address is quick switching (NOT to be confused with short term listening btw). The ability to instantly switch from one amp (cable etc) to the other without delay, withing the same musical passage and space. That feature is quite often found in dbts (ironically giving the person a greater chance of success than the usual couple of minutes delay used by the golden ears) simply due to the difficulty of organising that. Well, organising a rigorous dbt is such a hassle may as well take that little bit extra to include instant switching too.

Do YOU think that being able to swap between amps within a second is more or less sensitive than stopping, getting up and re-wiring, then sitting back down and re pressing play?

I hope you can at least see that these dbts are not as clearly 'bad' as you previously expressed, and indeed that in many ways they far far exceed the usual audiophile audition process by an order of magnitude.






I can't always play that loud but I at least like listening to music loud enough so that background instruments are given enough wattage to sound fully formed and musical (60-70db with 120watts driving).

But that is a whole new experiment isn't it?? In the case of the former I can see the original post is very probable true. With the latter we may begin to hear some differences I suspect but today I have to say I do not have enough experience with any amp nor speakers to say for sure.
Well, what conclusion would you draw from that instance then?Per the argument going on at the moment, we have an inadequate (ie not enough power) cheap amp that 'fails' at high volumes bested by an expensive audiophile amp (just cause that is how these arguments go ok??:nerd:)

Would your conclusion be 'Oh, there ya go you naysayers, we do need expensive audiophile amps after all' or 'huh, maybe the bigger brother (or the brother after him if needed) of that cheap amp which matched the expensive name brand all the way till it simply ran out of puff) is all I need".

WHY are these 'a-ha gotchas' always organised that way? That the expensive amp can out match the cheap on at high volumes, thereby justifying the excesses of the audiophile world that way?

Why not ever go the other (far more likely) road that the horrendously expensive flea watt powered valve amp (that will basically clip on almost any speaker out there) vs the high powered pro amp that will never run out of puff?

Because it does not suit the purpose and simply shows that the ONLY thing here is to try and find justifications for their stance. As I said earlier, very very few people are genuinely curious.
 
#262 ·
This has been a very nice discussion and I've felt everybody has been very respectful of thoughts and opinions and most of the discussion has focused on clarifying definitions terms and words used. Certainly sarcasm has not been used as a tool to help clarify meaning. It might be important to refrain from describing personality types or stereotypes since we really are discussing potential differences in amplifiers not people. Please???

Sorry, I was enjoying the healthy discussion. I have some fear of attack now but I'll just add.

I have a friend who designs and builds speakers for a living. We both like to experiment and talk about electronics and sound especially. People travel from quite a distance to buy one or some of his creations and Rogers opinions are highly regarded. We had come to a relative agreement 20 or so hears ago that the speaker has the greatest impact on sound Roger did not included wiring in any discussion except wiring needed to be adequate. But I was not so quick to agree on that aspect of the sound system.

I can accept that amps of similar design and with high impedance in and low impedance out, when level matched will sound indistinguishably similar. What happens when I turn up the sound to reference levels??? By reference I mean if a sax were in the room my speaker levels of a sax would match the volume (loudness)of the live sax and all else being proportional (80db approximately). I can't always play that loud but I at least like listening to music loud enough so that background instruments are given enough wattage to sound fully formed and musical (60-70db with 120watts driving).

But that is a whole new experiment isn't it?? In the case of the former I can see the original post is very probable true. With the latter we may begin to hear some differences I suspect but today I have to say I do not have enough experience with any amp nor speakers to say for sure.
 
#264 ·
I do remember Dunlavy quite well but did not know about the cable issue. Interesting.
You bring up a ton of points for which I would like to enter into further discussion. However, I think right now I will be attending Saturday Night at the Movies at the Jack house for tonight's showing of the new Total Recall. Now this may be a bias, but I am not so much looking forward to this disc even though it got some high marks. Never the less, I just have to experience it at least once, and will attend to further discussion tomorrow.

You know you are right in that some of my thoughts just do not express well here, it seems too many years of writing short, sweet legalese has taken its toll on smooth well thought out phrases. After reading my post I do seem to skip about a bit. Will have to work on that.

To be continued....
 
#266 ·
hi Jack (got your name from greg!) (I might not directly respond to yours greg, but some of these might touch on your points?? in any case, don't bow out, how is that in keeping with wanting to learn???:dontknow:)

I did a very quick search for john dunlavys comments, I did not find exactly (what I thought) I was referring to so maybe over the years I added a bit in my mind (?) but anyway, this gives the gist of his thoughts on cables

http://www.verber.com/mark/ce/cables.html

He at least makes the main point of mine that the audiophiles made flowery descriptions of the improvements when nothing at all was changed. (that at least allows me to apply it to amps).

I think this is where most of the disbelief comes from, 'yeah I get we can be influenced, but to THAT degree? So much we can start hearing things???' The disconnected channel on the mixing desk is a well known classic example of that as mentioned in my last post. Kind of an insiders joke to those guys, works every time.

So to me that is the biggest stumbling block, the complete unreality of how much we can fool ourselves so to speak. And, until someone takes the time and effort to give this a go they will never comprehend it, and why I so easily dismiss their rigid adamant position that what they heard was down to pure sonic differences and nothing else.

You simply do not and never will know that till you do the test.

It is not so much your inability to express yourself at all, but you do (perhaps instinctively) simply bring up all the tired old objections *we* have heard a thousand times before, that's all. Some of them just do not stand up to inspection...'well blind tests are worthless because we need time to hear these differences' yet whenever they audition at home these differences are usually jaw dropping, so much so that my wife (who is not interested in audio) heard them from the kitchen whilst cooking the evening meal.

So why then the need to point out it takes a month or so to hear differences? nOPE, SMACKS of an ad hoc construction or objection, that's all.

Let me ask directly, accepting as I do how confident you are of the reality of those differences, why would those differences disappear simply because you don't know which was which? (if that is what happens)

Or alternatively, what worth are those differences if they only appear when you know which is which?

That is what is laid out here, think of it as a possibility only. And like any proposition, it can only be shown to be true or untrue if it is actually tested, not simply theorised about. You might do a properly conducted blind test and ace it, if so then well and good. Not only have you then done the test as laid out, you are also able to reject that hypothesis.

The point is it needs to be done, not just blindly rejected with nothing to back it up other than blind confidence.

For what it is worth, I'll tell you why I kinda made that first post I did (that it's all well and good to make blind statements but they have little worth without evidence/experience to back it up).

On another forum recently someone made the comment that earle geddes feels all that is needed to design a good speaker is to use measurements. In other words, he feels that once you know what is important or not then all you need to do is ensure the speaker does those things and does not do what is bad to do.

Gee, tortured language there but I hope it is clear enough.

Ok, of course all the audiophiles rejected that immediately. Man, you start to pull your hair out ya know??

How many speakers have YOU designed mate? Of course, none. All he does is buy gear and swap them, this cable or that interconnects, these little cable lifters, the list goes on.

I mean, what earthly basis has THAT guy got to reject earles belief?? Man, he has not ever even used REW to measure his system, let alone has enough knowledge data or experience to even have a leg to stand on to begin to dispute the hypothesis.

I mean, that audiophile could be completely right, but he has no idea or experience to show that...so if he is right then it is nothing more that pure luck that makes him right.

Same deal here, the hypothesis is that if sighted we are liable to from erronous conclusions. You cannot falsify that if you never test the non sighted to see if it is true or not.

I got zero problems with people hearing differences, just do not (without testing the hypothesis) simply reject it as being untrue. You have no idea if it is true or not because you have not tested it. (again, the you there being 'everybody' or whatever)

As an aside, I have set up and run dbt's, so I am here to tell you that to do it properly is not a walk in the park, it is not a simple afternoons rig up. To do it properly takes a commitment (why bother ruining it by carelessness?).

All that means is that the urge from *our* side to do a dbt from those who have no idea how much work is involved is equally a little misleading. Both sides of this eternal argument often behave in less than ideal ways.

Take this or leave this, but one thing I have noticed is that those who get involved in the minutiae of audio often don't see the forest from the trees. You guys on this forum at least (I assume) have and do use rew and have at least got an idea of how your system measures, so in many ways even tho we are having this 'argument' you are light years ahead of the truly subjective guys. Those dudes actually reject measurements of any description, it is a way of life, belief and mantra for them. Measurements have no use at all and you must simply trust your ears.

So these guys who are into caps, different resistor brands et al (and of course cables and amps natch) truly have no reference point other than 'what they are used to'. That's ok as far as it goes, personal listening pleasure and all that jazz......but boy when an outsider who has not gone down their rabbit hole of tweaking the minutiae hears their system 'cold'.....you kinda shake your head a bit ya know?

I know that can never be a universal experience, but common enough in mine. They are chasing down these absolutely tiny effects that loom large in their own minds (ALL completely sighted and carrying this huge bundle of expectations and god knows what else along with it).....and you hear the system and go Unbelievable!?

It is usually so idiosyncratic by that stage that except to that tiny group it has no reality for anyone outside of it. They simply lost their way chasing these tiny effects (that are tiny, even in principle) yet doing it sighted and hearing all these ear opening moments they have forgotten even the basics of 'let's at least get rid of these twenty db peaks' and such. They do not even know those peaks are there and they reject that there is any worth in finding and fixing them.

Just one example of many of how easy it is to get lost in these detours, and completely rejecting the mere though of ''well, have you ever tried this mod objectively? You know, get your wife to switch it in and out and not tell you?"

No, they are immune from bias and their ears are the most exquisite measuring device in the known universe and science does not know everything and measurements are useless.

That's my little rant for the day haha, thanks for letting me tell it!


So yeah, it's all well and good to have a belief, but at least have the intellectual honesty to KNOW it is a belief.
 
#265 ·
Terry J. you begin with a description of an argument or at least you used the word. I have no interest in an argument of any description. The first 5 pages of this thread have been very interesting as an unbiased exploration of sound amps and personal experience. I felt Savac (Jack) was doing a great job of describing my experience. I've had purchases where I felt I had made a good move and others I questioned in the beginning but learned to love. I would attribute the learning to love with the concept of "Set Point". Whereas as your ability to hear (smell taste or any of the senses) changes and if your intent is to hear music you will negate sound characteristics that get in the way of you hearing music in the sound you are given.

Some complain every time the system is turned on the sound system takes time to warm up (so to speak) before reaching the systems full musical potential. I believe some of this warming is the mind readjusting to hear the systems full musical potential through any "slight" discordant sounds.

I am having a very difficult time understanding this recent dialog so I'm going to sigh off.

I will agree to disagree, until I have more info about what just happened.
 
#267 ·
First, a personal, sincere note of appreciation to all that we can discuss this extremely fun topic with such passion and continue being nice to each other! Big smiles! Only at Home Theater Shack!

One point that shows up time and again is the value in being able to take time to listen, time for a change to settle in and be recognized. It is true, I believe, that extended listening time is important in helping us learn how to listen and what to listen for. We all are better listeners now than we were five years ago, 10 years ago, maybe a week ago. Our listening brain is a muscle constantly being fine tuned and refined, and the aha moment that occurs in a certain passage of music two hours into a listening session is no less important than the aha moment when switching between speakers in a showroom, or when switching from amplifier a to amplifier b in a DBT. Contrasts, or lack thereof, tell us a great deal, but they rely upon the time in between. How long? A few seconds, minutes, an hour? The listening brain has different time constants at work, and the nature of those time constants may be different for different listeners. Perhaps one listener is more accurate in a DBT with 20 second segments between switches, another with 2 min., another with an hour. Plus, some listeners may get better after the first few A-B switches, so maybe you throw out the first four tests and see how the next 10 go?

Is there any validity in customizing a DBT to the listener's preferences, give the listener the best chance of success, including comfort, relaxation, a glass of wine, the presence of supportive friends, but still with true DBT rigor - versus setting them up to fail? How well would you expect anyone to do when under the gun, in a semi-hostile test environment where she/he knows the testers would like them to fail? While I understand quite well the principles behind DBT, I am not a student of the nuances and details that have been found to work best. What do the experts say about this?
 
#269 · (Edited by Moderator)
First, a personal, sincere note of appreciation to all that we can discuss this extremely fun topic with such passion and continue being nice to each other! Big smiles! Only at Home Theater Shack!

Is there any validity in customizing a DBT to the listener's preferences, give the listener the best chance of success, including comfort, relaxation, a glass of wine, the presence of supportive friends, but still with true DBT rigor - versus setting them up to fail? How well would you expect anyone to do when under the gun, in a semi-hostile test environment where she/he knows the testers would like them to fail? While I understand quite well the principles behind DBT, I am not a student of the nuances and details that have been found to work best. What do the experts say about this?
In a real world, yes to all of your points. AFAICS, if we (all of us) are honest about being honest, then everything possible should be done to maximise the chance of success. Just a few off the top of me 'ead, ideally any test should be done (for example) on the persons own system. After all, that is the one that they are not only most familiar with, but also (in most cases) the only system they are making claims for. It is not much use really to throw them into a completely new environment with completely new gear is it.

Also as yet another example, it should be limited to the exact amps that person claims to be able to tell apart...again not much use really in throwing an amp at them they have never heard and make no particular claims for. Unless of course they are claiming all amps on all systems are different...a claim I have not seen made here.

In all cases the methodology and procedure should be completely familiar to them, take as long as needed to become acquainted with it.

The choice of music should be the testees, and they are completely free to choose the 'killer' section of any track. They have the choice of when to switch, they also have the choice of how to switch (some might be happy with a switch inserted to allow instant switching, others may wish to manually swap ICs and speaker cables)

Once they are familiar with how it is run (that takes as long as it takes) they can listen for as short a time or as long a time as they want, there should not be any restrictions there. Usually it is done sighted first and only when they are confident does it move on to the blinded part. There is no point in going on to the blind portion until and unless the person is certain they can tell a difference.

Having said that, I am equally sure you can see how limiting that is as well, bit of a double edged sword I am afraid.

It is understandable that some may feel that the tester 'wants them to fail' when viewed solely from forum posturing. It often devolves to that in many arguments, but on the whole when finally face to face it does not turn out that way, at least in my experience. (truly, these differences or antagonisms fade away face to face...the curiosity and interest remains however)

But, as always, it comes back to a genuine desire to learn, and that desire needs to come from BOTH sides of the fence. (just as an aside, that is why it needs to be a true dbt...if it is then the tester as well as the testee have no idea of which is which. IF it is true that the tester 'wants' them to fail, at least they are not in a position to influence the outcome...see that it is fair to both sides in that regard???)
 
#270 ·
The other thing is that there are a lot of DBTs.

Harmon Kardon, for example, does DBTs for speakers (they also did them for cables and the like); and in the speaker DBTs there are differences found and there are consistent preferences produced.

Why is it that DBTs work for finding differences in speakers but not in level-matched amps?

DBTs also work in foods, scents, and any number of other things.
 
#271 ·
This is a good question but I personally do not think they always work well. The folks being tested are not comfortable and I am sure they feel they HAVE to perform or they fail. Second, imo, in what other like of products does the items in question have to be manipulated between the source and the end of the line, in this case being the speaker. Level matched, make sure they are operated only within their limitations and so on. This just does not seem natural to me. In doing a truck comparison, would it be proper to lower the horsepower of my Tundra to that of the basic Silvarado so that they are both the same and nothing has an advantage. That would be silly beyond belief as I would have no idea how either vehicle operated in the real world. A DBT of the vehicles would have them both matched in HP, weight, speed, and quality of components, warranty and many other things. Do we do the same for blenders, both operate on 120 volt system but because one is more powerful we cut back the amount of power to it so it operates with the same crunching abilities as the lesser unit ? No that would not be good either.

In sports should we use a DBT for the athletes and only test them in perfect weather on a perfect sunny day with no other players or audience ? I mean that is when the athlete is really tested is on the field doing what they do in front of millions of viewers....no pressure there.

There really is nothing I can say that would convince those that truly believe in the DBT test that maybe it is not perfect and until I am proven wrong I will believe I can hear some differences in equipment. I guess that is about all I have as it has already moved into way too many subjects already.
 
#274 · (Edited)
Very interesting argument regarding making the test subject comfortable as I had not thought about that. In the testing scenario's I participated in there was no lack of confidence on the part of the participants. Maybe the audiophiles I met in those days were unique in that they were confident to a fault. They were absolutely certain they could hear differences in amplifiers. Even those they had little familiarity with because they were convinced that the superior design, quality and care taken in creating the product would so greatly overshadow the so-called inferior product. Sure, there were arguments afterword that the test must have been flawed in some way but being comfortable and familiar with the test subjects was not a complaint.

Now, I can see why you might think a glass of wine, some soft lighting and an easy chair might help in making the subject more comfortable and subsequently hear better but my money would still be placed on the side of no change in the outcome. There are no perfect test methodologies but DBT's are the best we have in the audio world.

I would also like to add that although I pushed to have my particular amp DBT tested against some big dogs it was not my intent at all to have the test conducted in a manner that would insure my amp won. In fact, this test did not prove my amp was superior in any way - there were no winners or losers. The only outcome of this was that none of the participants could discern any sonic differences between the amps.

JD
 
#275 ·
Yeah I kind of new this would happen. Change trucks to batteries then we should change amps to capacitors.

There is no strawman as there is no fallacy. The information about the DBT test indicates the amps cannot compete against one another without having some controls introduced thereby making them more equal on various levels.

This is like discussing religion or politics, each participant has their beliefs and those beliefs are unlikely to be changed by any rhetoric. Thanks for the exchange, its just too frustrating for all parties so it is time to go listen to things I cannot hear. Should be interesting.
 
#276 ·
Yeah I kind of new this would happen. Change trucks to batteries then we should change amps to capacitors.
Again: analogies get you so far, but eventually fail.

Change batteries to trucks and we should change amps to "systems including room treatments".

But of course the truth of analogies is in their utility. The comparison is inept: therefore a bad analogy.

There is no strawman as there is no fallacy.
That sentence doesn't actually make sense in English.

"Do we do the same for blenders, both operate on 120 volt system but because one is more powerful we cut back the amount of power to it so it operates with the same crunching abilities as the lesser unit ?"

Let's try that

"Do we do the same for aplifiers, both operate on 120 volt system but because one is more powerful we cut back the amount of power to it so it operates with the same crunching abilities as the lesser unit ?"

We don't lower the power on amps in DBTs. We adjust the gain on either the amp or the pre-amp to match volumes. If we did not: then you would always hear a difference. One would be louder than the other.

The information about the DBT test indicates the amps cannot compete against one another without having some controls introduced thereby making them more equal on various levels.
In this case you are arguing against amps being identical under all circumstances. But no one has claimed that amps are identical under all circumstances. This is therefore another straw-man argument.

This is like discussing religion or politics, each participant has their beliefs and those beliefs are unlikely to be changed by any rhetoric.
Yes. Except that in this case it's a heavily tested science which is used throughout almost every industry in existence in order to create more appealing products. Another bad analogy :(
 
#278 ·
As stated earlier... a man's opinion changed against his will is of the same opinion still.

The biggest difference in the two sides right now is that those who say that they cannot hear a difference have objective proof to back up their claims, while those that claim they can hear a difference have yet to provide any objective proof... and ironically some of those are not willing to subject themselves to objective testing that would prove otherwise. That is pretty convenient.
 
#279 ·
Savjac, how would you feel about a $200 AVR being declared sonically superior to any system you care to specify simply because its output volume was set 1.5dB higher in a blind test (notice I said blind not double blind) because that is exactly what would happen.
Same thing would happen in double blind but it is nothing to quibble over.

I don't think anyone here is opposed to owning and enjoying 'high end' electronics or even 'high end' cables.
Where the objections come from is in response to the pseudo science the audiophile community and manufacturers push as truth.
In the past it may have been possible to discern differences in electronics, but now all of the components are commodity items and the tools available to electrical engineers allow designs where variations are measured to the third or forth digit.
There is nothing magical about electronic circuits, what is factual is audio circuits are very simple comparatively speaking and the component values necessary to alter audio frequencies is very large so it is actually pretty hard to screw it up.
 
#280 ·
Hello all,


Getting back to the original post, it is important and I believe customary to accommodate the challenger to the highest degree possible. In this instance there can be no denying the outcome and the assigning of a high degree of validity to the statement of two similar amps being indistinguishable from one another when played within specific parameters. I would think the Zipser challenge clearly proves the point of the original premise in that Zipser was given ample opportunity. This is a clear benefit of accommodating the challenger while maintaining the parameters of the original study question. To clarify here is the original statement …


“If amplifiers A and B both have flat frequency response, low noise floor, reasonably low distortion, high input impedance, low output impedance, and are not clipped, they will be indistinguishable in sound at matched levels no matter what’s inside them. Of course, some of the new “alphabet soup” topologies do not necessarily satisfy those conditions.”

Read more: Can we really hear a difference between amps? - Home Theater Forum and Systems - HomeTheaterShack.com


I can accept this…, I am confident Zipser was provided every opportunity to do his best to prove his point. I believe the outcome of the Zipser study clearly demonstrates the original statement is True and that the Zipser claim to hear a difference is in fact false. But in our discussion I sense certain assumptions have been added to the meaning of the result described above.



In any case if we were to perform a statistical analysis of the Zipser study I am confident we will find the original study question is a question with a high degree of validity. With regard to the result I believe any statistician will ask for more testing. The testing should include a broader base of amplifiers and a greater number of participants and probably a greater number of trials. As I said I am confident this study strongly indicates the original statement is true to a relatively high degree but with greater numbers of people and amps included in testing and with the same result it would then be completely ethical to make a statement that will read - amps of similar design when played at equal levels will always sound indistinguishable from one another.


…but I wonder about higher volume levels.


I wonder also, if claims have been made a thousand times…, well, maybe there is some (more than one) real truth in that mix of ideas. Typically I find there is not much truth in all or nothing thinking. In my 60++ years I do not believe I have ever found where any one belief or bit of knowledge or experience is the single authority on any subject. This is true for science and technology as well as religion and politics and human behavior as well.


The quotes I’ve read are simply one added opinion. Granted the people quoted have years of experience but when it comes to opinion it is simply one more. It is the study result that says it all and what is that saying...


A few additional thoughts…, I think Zipser was shocked to see the result and the 4:10 was telling but the 6:10 result was less telling. In fact the 6:10 could indicate there is some distinguishable difference between the two amps. I am not sure what a random result would be. I do know this I am completely enjoying my search and my own experiments. I do believe my cheap Denon amp sounds pretty good in general. I do believe the Zipser study shows that is true. I believe I’ve also seen a cumulative improvement in sound stage and musicality as a result of changes to the system over the years and speakers being the greatest improvement.
 
#289 ·
Hello all,

A few additional thoughts…, I think Zipser was shocked to see the result and the 4:10 was telling but the 6:10 result was less telling. In fact the 6:10 could indicate there is some distinguishable difference between the two amps. I am not sure what a random result would be. .
To me this is exactly what happened a random result, if you flip a coin you would average 5:10, if you do the test over and over you may even get 8:10 or 2:10.

If there is an audible differnce then he should get 10:10, if he gets 8 or 9 out of 10 consistently, then I would say there is something very sutile.
 
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