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post #91 of 139 Old 03-08-2008, 03:52 PM
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If someone here "claims" they can hear the difference between amps WHEN level matched and below clipping, check out the link...

http://www.tom-morrow-land.com/tests/ampchall/index.htm

I agree with those who state room acoustic are the MOST important factor for SQ. Speakers make a good difference, but not nearly as much as room treatments. Electronic equipment will give subtle performance increases when compared to Room and Speaker gains, and will also mostly be the pre-amp section that gives the most improvements in sq when comparing amp, pre-amp, and source components. As long as I had a capable amp, I would absolutely upgrade my pre first, followed by source equip (which is almost always VERY minor gains).
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post #92 of 139 Old 03-08-2008, 04:51 PM
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Originally Posted by SleeperSupra View Post

You are forgetting about things like slew rate, settling time, excessive distortion, DIM, PIM, TIM, both amplifiers could be clipping but one has better overload recovery, bias, the use of negative feedback...

There are many things that determine the way an amplifier will sound.


The only things you mention that are audible are clipping and distortion. Properly designed modern amplifiers don't have audible distortion. Clipping is very audible but not descriptive of a properly functioning amplifier.

Why would anybody want an amplifier with a characteristic sound. What you should want is one that increases the amplitude of the input without adding anything to it or subtracting anything from it. I have no problem with signal processing but why on earth would you want an amplifier to do it?
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post #93 of 139 Old 03-08-2008, 10:10 PM
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Quote:
Originally Posted by gunbunnysoulja View Post

If someone here "claims" they can hear the difference between amps WHEN level matched and below clipping, check out the link...

http://www.tom-morrow-land.com/tests/ampchall/index.htm

I agree with those who state room acoustic are the MOST important factor for SQ. Speakers make a good difference, but not nearly as much as room treatments. Electronic equipment will give subtle performance increases when compared to Room and Speaker gains, and will also mostly be the pre-amp section that gives the most improvements in sq when comparing amp, pre-amp, and source components. As long as I had a capable amp, I would absolutely upgrade my pre first, followed by source equip (which is almost always VERY minor gains).

Room acoustics is important but not the MOST important factor in SQ; the most important factor in SQ is the recording.

To give you an analogy, if I play a Stradivari violin in Carnegie Hall , it's gonna sound like shiet. But if Jascha Heifetz playing some random violin in some random 24hr fitness center, it will sound great regardless of the make and location. So it doesn't matter how good your playback system or your acoustics are, as long as you have junk input, the output is going to be junk regardless.

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Originally Posted by FMW View Post

The only things you mention that are audible are clipping and distortion. Properly designed modern amplifiers don't have audible distortion. Clipping is very audible but not descriptive of a properly functioning amplifier.

Why would anybody want an amplifier with a characteristic sound. What you should want is one that increases the amplitude of the input without adding anything to it or subtracting anything from it. I have no problem with signal processing but why on earth would you want an amplifier to do it?

Because that is not possible to have a entirely flat amplifier. Simple enough answer? Properly designed modern amplifiers will have certain FR, phase/impedence variation, SNR, pull-up/pull-down delay, etc.

And inevitably the amplification stage/output stage will interact with the crossover network within your speakers. Thus the importance of matching amplifier with speakers.

Sorry to burst your bubble, but your dream amplifier is simply not achievable with modern design. Electrical Engineering 10a.
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post #94 of 139 Old 03-09-2008, 12:13 AM
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Originally Posted by vitaminc View Post

Room acoustics is important but not the MOST important factor in SQ; the most important factor in SQ is the recording.


Agreed, although the recording of source material is out of ones control, therefore not mentioned.

I would imagine when having a discussion of methods to take to obtain improved sq, a reasonable person should be able to assume we are referring to control options (aside from "selecting" well mastered material).
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post #95 of 139 Old 03-09-2008, 07:08 AM
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Originally Posted by vitaminc View Post


Because that is not possible to have a entirely flat amplifier. Simple enough answer? Properly designed modern amplifiers will have certain FR, phase/impedence variation, SNR, pull-up/pull-down delay, etc.

And inevitably the amplification stage/output stage will interact with the crossover network within your speakers. Thus the importance of matching amplifier with speakers.

Sorry to burst your bubble, but your dream amplifier is simply not achievable with modern design. Electrical Engineering 10a.

You are talking about measurable differences and I'm talking about audible ones. Trust me, my bubble is not burst.
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post #96 of 139 Old 03-09-2008, 07:19 AM
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Because that is not possible to have a entirely flat amplifier. Simple enough answer? Properly designed modern amplifiers will have certain FR, phase/impedence variation, SNR, pull-up/pull-down delay, etc.

And inevitably the amplification stage/output stage will interact with the crossover network within your speakers. Thus the importance of matching amplifier with speakers.

Sorry to burst your bubble, but your dream amplifier is simply not achievable with modern design. Electrical Engineering 10a.

You're talking about measurable differences. We're talking about audible differences. Psychoacoustics 10a.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #97 of 139 Old 03-09-2008, 12:15 PM
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Strange rules regarding URLs....
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post #98 of 139 Old 03-09-2008, 12:18 PM
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So, measurable differences in an amplifier do not affect audible perception? I think it most certainly does, but certain types of distortion can be more 'audible' than others. Phase distortions are not given enough credit as to their negative effects on sound. This paper has a little more info on the effects of transient distortions. However, I'm not so certain if slew rate, by itself, has such an effect on musical perception. This paper is an interesting read on that issue.
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post #99 of 139 Old 03-09-2008, 12:36 PM
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So, measurable differences in an amplifier do not affect audible perception?

Sure they do, if the differences are large enough. But for most modern amps, the differences you find are not large enough to produce audible differences.

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I think it most certainly does, but certain types of distortion can be more 'audible' than others.

The second half of this sentence is certainly true. But that doesn't mean any differences are large enough to be heard.

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Phase distortions are not given enough credit as to their negative effects on sound.

That's because the evidence that phase distortions (of a scale you'd get in an amp) are audible is very thin.

Just as a note, neither of the papers you link to is discussing audibility. But the latter one provides indirect evidence that slew rate is unlikely to be a factor in audibility.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #100 of 139 Old 03-09-2008, 03:14 PM
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Quote:
Originally Posted by FMW View Post

You are talking about measurable differences and I'm talking about audible ones. Trust me, my bubble is not burst.

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Originally Posted by mcnarus View Post

You're talking about measurable differences. We're talking about audible differences. Psychoacoustics 10a.

You can either continue to refute measurable differences within audible range of 20Hz-20kHz or argue that there's no audible difference between Sonic T-Amp and Accuphase P8000 driving a pair of Sonus Faber Stradivari.

Psychoacoustics, placebo effect or snake oil?
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post #101 of 139 Old 03-09-2008, 03:55 PM
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You can either continue to refute measurable differences within audible range of 20Hz-20kHz or argue that there's no audible difference between Sonic T-Amp and Accuphase P8000 driving a pair of Sonus Faber Stradivari.

Of course there's a audible difference between those two amps. The Sonic T will clip like crazy. No one's said that clipping doesn't matter. Are you reading the posts you're replying to?

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #102 of 139 Old 03-10-2008, 06:15 AM - Thread Starter
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Originally Posted by mcnarus View Post

The basic theory is that two amps will sound alike unless:

1) One is playing louder than the other.

2) There are audible differences in frequency response (which can often be caused by impedance mismatches, particularly in the case of tube amps).

3) One is clipping.

So if you hear an amp as more forward or warmer (whatever that means to you), it has to be caused by one of the conditions above.

Now, here's the thing: Among modern solid-state amps driving typical home speakers, it is very rare for conditions 2 and 3 to hold. As for #1, that has nothing to do with the character of the amps, and everything to do with where you set the volume control. Tweak it a little, and both amps will sound the same.

So your next question is, OK, if that's all true, why do I and other audiophiles hear differences between amps? Three reasons:

1) You're comparing without matching output levels, which has to be done very precisely (i.e., your ears and/or a Radio Shack SPL meter aren't enough; you need a voltmeter measuring the signal at the speaker terminals).

2) You aren't comparing the two side by side, but are relying on your long-term memory of the sound of one of them. Our long-term memory of subtle sonic differences is really poor.

3) You are subject to what the psychologists call "bias," which simply means that your hearing perception is influenced by other factors--specifically, other things you think or know about the amps. If some salesman once told you that Brand X tends to be warm, that's liable to affect how you hear Brand X. Can't be helped, as you're only human. That's why scientific listening comparisons are always done blind.

Needless to say, all of this is highly controversial within the audiophile community. And since it's only a hobby, it's perfectly OK to ignore it. But nothing I've said above is even remotely controversial within the scientific community.

Now, pardon me while I don my flame-proof suit.


Hmmmm. Interesting mcnarus. It all sounds good to me and makes sence. Thanks.

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post #103 of 139 Old 03-10-2008, 11:06 AM
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Originally Posted by vitaminc View Post

You can either continue to refute measurable differences within audible range of 20Hz-20kHz or argue that there's no audible difference between Sonic T-Amp and Accuphase P8000 driving a pair of Sonus Faber Stradivari.

Psychoacoustics, placebo effect or snake oil?

Got me. Not only have I never tested these, I've never even seen them. However, I can tell you that a claimed audible difference between them without the use of a bias controlled test to determine that would be worth about the same as a used piece of chewing gum to me.

If the manufacturer has engineered a "sound" or "voicing" into the amplifier then that amplifier is worthless to me as well. I would want the amp to amplify without audible distortion, noise or frequency response anomalies. It is a trivial thing for designers and engineers to do. They do it all the time. The designers of the two amps you mentioned are perfectly capable of doing it as well so there is no reason to think they did something else. But only a bias controlled test can tell for sure.
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post #104 of 139 Old 03-10-2008, 11:24 AM
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The designers of the two amps you mentioned are perfectly capable of doing it as well so there is no reason to think they did something else.

You may be presuming too much here.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #105 of 139 Old 03-10-2008, 04:15 PM
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One needs to think about how long they have been listening to audio and the ability of the ear's perception to what it can pick up in the music. I have been involved in just plain listening and information gathering as a hobby with 2 channel stereo and will say that after 40 years of all different levels of quality in audio components I can definitely hear audible differences in better equipment. I will agree with some about the quality of speakers having the most initial improvement but after one has had lets say a real good set of speakers they know that there are ways for them to sound even better, no matter where they are located. I have a pair of Linn's hooked up to a 60 wpc Adcom amp presently, but I am becoming increasingly convinced that my Yamaha pre is where I will get the most improvement in sound at this time. I to for many years thought that speakers were the main improvement factor but now I am not so sure. Of course it may take years to develop hearing differences in equipment but I now think that source equipment can make a real difference in sound quality. Anyway I just love it when I walk into a high end audio dealer and hear someone like KD Lang or Lindsay Buckingham on a high end system motivating me to continue striving for better quality which keeps most of us in this hobby anyway. The recording also plays a role but the combo of great recording and great sounding system is truly awesome. Love reading all of the comments posted here.
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post #106 of 139 Old 03-10-2008, 05:34 PM
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My $0.02...

The "sound" of a system is a creation of your central nervous system, influenced by a number of factors, not the least of which is bias. Amplifiers of different specification are different but may not determine whether a system "sounds" different.

So, if you think my Marantz integrated amp and your Rotel separates create a different sound when used within the same tolerances with the same source, speakers, room treatments, etc, then I wouldn't argue. I tend to believe that amplification devices of similar specification used within similar parameters, and not driven to distortion, are for the most part interchangeable.

It's all in the ear/mind of the beholder.

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.
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post #107 of 139 Old 03-11-2008, 04:19 AM
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Originally Posted by Erniek View Post

One needs to think about how long they have been listening to audio and the ability of the ear's perception to what it can pick up in the music. I have been involved in just plain listening and information gathering as a hobby with 2 channel stereo and will say that after 40 years of all different levels of quality in audio components I can definitely hear audible differences in better equipment. I will agree with some about the quality of speakers having the most initial improvement but after one has had lets say a real good set of speakers they know that there are ways for them to sound even better, no matter where they are located. I have a pair of Linn's hooked up to a 60 wpc Adcom amp presently, but I am becoming increasingly convinced that my Yamaha pre is where I will get the most improvement in sound at this time. I to for many years thought that speakers were the main improvement factor but now I am not so sure. Of course it may take years to develop hearing differences in equipment but I now think that source equipment can make a real difference in sound quality. Anyway I just love it when I walk into a high end audio dealer and hear someone like KD Lang or Lindsay Buckingham on a high end system motivating me to continue striving for better quality which keeps most of us in this hobby anyway. The recording also plays a role but the combo of great recording and great sounding system is truly awesome. Love reading all of the comments posted here.

Yes, I've been involved in it for more than 40 years. I once believed like you that I could hear better than other people. I call it the "golden ears" syndrome. But it wasn't true. I can promise you that, in a bias-controlled listening test, the number of years you've listened to audio doesn't mean a thing in the test results. Men, women, children, audiophiles, musicians, non-audiophiles, all scored the same in the tests we conducted. Most of the test subjects in our tests were a group of 9 hard core audiophiles and not a single one of them had "golden ears" as it turned out.

There is no doubt that there are audible differences in some source components. They can range from fairly obvious with vinyl record playback equipment to non existent with properly designed CD players. Certainly there were more audible differences between source components 40 years ago than there are today. The difference between a high end Nakamichi cassette deck and a mid fi cassette deck in the 1970's or 1980's was so obvious that a bias controlled test wasn't even necessary. That's certainly not true of modern CD playback equipment. Finding an audible difference anywhere in CD playback today is true rarity.

All I can suggest is that, if you haven't engaged in bias controlled listening tests, then you haven't learned the truth about your hearing (and everybody else's.) Go do some bias controlled tests. You'll see what I mean.
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post #108 of 139 Old 03-11-2008, 09:12 AM
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Originally Posted by Erniek View Post

Of course it may take years to develop hearing differences in equipment

Medical facts:

1) Hearing gets worse with age. Doesn't matter what you do.

2) It is possible to train _some_ people to differentiate between audible signals that your average listener won't pick up. Though it's been years since I looked at this kind of testing, from what I remember for the most part this ability is not retained over repeated tests over periods of even months, least of all years.

If you have access to a PC that can be hooked up to your system, there are a couple of relatively easy tests you can try at home. If you don't want to just fool yourself it's best if you have someone else run the tests and record the results:

1) Whats the highest frequency sine wave you can hear?

2) What is the highest frequency added sine wave you can detect 0db and -3db down in pink noise?

3) For what range of frequencies can you reliably detect 45, 90, etc. degree phase differences between two channels? (Not so sure if you'll be able to find a way to do this.)

4) Whats the highest frequency for which you can reliably tell the difference between a square wave and a sine wave in two different channels?

Anyone claiming they can hear difference between amps should try this out first. Fact is most of us aren't hearing nearly what we think we are, even when if our hearing happens to test out better than average.
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post #109 of 139 Old 03-11-2008, 02:04 PM
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Originally Posted by mcnarus View Post

Of course there's a audible difference between those two amps. The Sonic T will clip like crazy. No one's said that clipping doesn't matter. Are you reading the posts you're replying to?

No, because you continue to refute the measurable differences from a circuit/system design perspective. It's a electronic system, designed by men using principals of engineering and science, thus can be modeled and measured as such.

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Originally Posted by FMW View Post

Got me. Not only have I never tested these, I've never even seen them. However, I can tell you that a claimed audible difference between them without the use of a bias controlled test to determine that would be worth about the same as a used piece of chewing gum to me.

If the manufacturer has engineered a "sound" or "voicing" into the amplifier then that amplifier is worthless to me as well. I would want the amp to amplify without audible distortion, noise or frequency response anomalies. It is a trivial thing for designers and engineers to do. They do it all the time. The designers of the two amps you mentioned are perfectly capable of doing it as well so there is no reason to think they did something else. But only a bias controlled test can tell for sure.

It's not the circuit designers trying to engineering a voice into the amplifier; it's the artifact of engineering.

For example, exact same speaker drivers with first-order crossover network and second-order crossover network will have different electric characterizations. And those crossovers will behave differently to the same exact amplifier, resulting in different 'voice'.

Same thing could be said to amplifiers; some choose to use single stage amplification with feedback loops and cascade an output buffer stage, some choose to do it using multi-stage amplification. Both could achieve the same spec (such as frequency response and transient response requirements, SNR, etc), but will behave differently as the volume or frequencies varies.

While less is more in terms of electronic design, it's always easier to achieve the intended spec with more leeway; the downside is residual effects, good and bad, induced by the additional components.
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post #110 of 139 Old 03-11-2008, 02:07 PM
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Originally Posted by scientest View Post

Anyone claiming they can hear difference between amps should try this out first. Fact is most of us aren't hearing nearly what we think we are, even when if our hearing happens to test out better than average.

The difference between amps isnt at the highest or lowest frequency or using snake oil turns, more transparent, spacious and such.

The difference between amps are the dips and peaks of the overall system's frequency and transient response and other electric characteristics.
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post #111 of 139 Old 03-11-2008, 02:21 PM
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Quote:


Of course there's a audible difference between those two amps. The Sonic T will clip like crazy. No one's said that clipping doesn't matter. Are you reading the posts you're replying to?

No,

That's what I thought.

Quote:


you continue to refute the measurable differences from a circuit/system design perspective. It's a electronic system, designed by men using principals of engineering and science, thus can be modeled and measured as such.

What does this even mean? I'm not "refuting measurable differences." I'm challenging the notion that measurable differences must necessarily result in audible differences.

Quote:


It's not the circuit designers trying to engineering a voice into the amplifier; it's the artifact of engineering.

If they're voiced, it's an artifact of bad engineering.

Quote:


For example, exact same speaker drivers with first-order crossover network and second-order crossover network will have different electric characterizations. And those crossovers will behave differently to the same exact amplifier, resulting in different 'voice'.

Demonstrating differences among speakers, NOT amplifiers.

Quote:


Same thing could be said to amplifiers; some choose to use single stage amplification with feedback loops and cascade an output buffer stage, some choose to do it using multi-stage amplification. Both could achieve the same spec (such as frequency response and transient response requirements, SNR, etc), but will behave differently as the volume or frequencies varies.

But the differences won't be audible, barring clipping or frequency response anomalies.

Quote:


The difference between amps are the dips and peaks of the overall system's frequency and transient response and other electric characteristics.

And the audible difference will be the result of "dips and peaks of the overall system's frequency . . . response" alone (absent clipping).

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #112 of 139 Old 03-11-2008, 02:35 PM
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Originally Posted by vitaminc View Post

The difference between amps are the dips and peaks of the overall system's frequency and transient response and other electric characteristics.

Simply put, NO!

A properly designed modern amp has a flat response across more of the audible spectrum than you can hear and better transient response than you can hear.

Had to Google "null test' and poke around a bit but it was pretty easy to dig up this 20+ year old result:

Science and Subjectivism in Audio

With a little bit of work you might actually be able to do a null test on the amplifier of your choice at home....
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post #113 of 139 Old 03-11-2008, 03:34 PM
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Originally Posted by mcnarus View Post

What does this even mean? I'm not "refuting measurable differences." I'm challenging the notion that measurable differences must necessarily result in audible differences.

The measurable differences within hearing frequencies are audible.

Quote:
Originally Posted by mcnarus View Post

If they're voiced, it's an artifact of bad engineering.

No. It's called electronics design 101, which is not an easy concept for non-engineering trained people to grasp.

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Originally Posted by scientest View Post

Simply put, NO!

A properly designed modern amp has a flat response across more of the audible spectrum than you can hear and better transient response than you can hear.

Had to Google "null test' and poke around a bit but it was pretty easy to dig up this 20+ year old result:

Science and Subjectivism in Audio

With a little bit of work you might actually be able to do a null test on the amplifier of your choice at home....

1. No, you are wrong. Go to TI or whatever SS component vendor of your choice, pull out a spec sheet of an Op-Amp that has completely flat frequency response from 20Hz to 20KHz for me. It's not simply not possible without inducing a lot of abnormalities. If it's too hard for you, let me put it this way, it is NOT possible to have a transistor with flat 20Hz to 20KHz FR and perfect impulse/transient, thus it is not possible to have a silicon chip to have the such properties, thus it is not possible to have an amplifier with such properties, thus it is not possible to have a sound system to have such properties without adding some artifacts to compensate.

2. The bibliographies refers to stereophile and hifi-news, making the article as trustworthy as those snake-oil advertisements. Further, there's no mathematical models or simulation results. Those cut-and-paste schematics are pretty worthless anyway.

BTW, you should considering applying for an ph.d. in electrical engineering if you know how to boost a certain frequency band without tempering with the phase, transient or other component characterization factors. It's going to be a major breakthrough in system design!
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The measurable differences within hearing frequencies are audible.

This is flat-out wrong. You can measure differences in frequency response in hundredths of dBs. Such differences are not audible, even if they are in the audible range. You can measure THD in thousandths of a percent. The difference between 0.002% THD and 0.003% THD is completely inaudible.

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Go to TI or whatever SS component vendor of your choice, pull out a spec sheet of an Op-Amp that has completely flat frequency response from 20Hz to 20KHz for me. It's not simply not possible without inducing a lot of abnormalities. If it's too hard for you, let me put it this way, it is NOT possible to have a transistor with flat 20Hz to 20KHz FR and perfect impulse/transient, thus it is not possible to have a silicon chip to have the such properties, thus it is not possible to have an amplifier with such properties, thus it is not possible to have a sound system to have such properties without adding some artifacts to compensate.

Again, you're talking measurability. We're talking audibility. When you have something to say about audibility, let us know.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #115 of 139 Old 03-11-2008, 05:59 PM
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Originally Posted by mcnarus View Post

This is flat-out wrong. You can measure differences in frequency response in hundredths of dBs. Such differences are not audible, even if they are in the audible range. You can measure THD in thousandths of a percent. The difference between 0.002% THD and 0.003% THD is completely inaudible.

Yes, some differences in hundredth or thousandth of a percentage point are probably not audible, but there are a lot more realistic cases that you can use as examples.

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Again, you're talking measurability. We're talking audibility. When you have something to say about audibility, let us know.

Measurability (is there such a word?) is objective and uses clearly defined matrix as common ground.

Audibility is completely subjective, can skewed by different factors such as alcohol or Placebo effects and uses your own experiences as the common denominator.

Your argument of indifference of amplifiers is probably true for my hard-hearing 95-year-old grandfather; he can't tell the difference between NBA on ESPN and NBA Live 2007 also. I hope you are not at that stage yet.
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post #116 of 139 Old 03-11-2008, 07:09 PM
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Yes, some differences in hundredth or thousandth of a percentage point are probably not audible, but there are a lot more realistic cases that you can use as examples.

Then how about you present us some examples to prove your point. Name any two amplifiers that, if not clipping and corrected for frequency response differences, can be distinguished in an objective listening test.

Here's a hint: You can't.

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Measurability (is there such a word?) is objective and uses clearly defined matrix as common ground.

Audibility is completely subjective, can skewed by different factors such as alcohol or Placebo effects and uses your own experiences as the common denominator.

There are objective tests of audibility. Just because you don't know the science doesn't mean the science doesn't exist.

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Your argument of indifference of amplifiers is probably true for my hard-hearing 95-year-old grandfather

It is also true of you, my friend.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #117 of 139 Old 03-11-2008, 10:08 PM
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Originally Posted by vitaminc View Post

The measurable differences within hearing frequencies are audible.

Pick a modern, properly functioning, transistor amplifier costing between $500 and $5000. I will personally wager you $500 that you cannot pick it, with any statistical reliability, over any other amplifier of my choosing in a double blind ABX. (You may want to know there are other's who have offered more money for this challenge and never found anyone who could perform the feat.)

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No. It's called electronics design 101, which is not an easy concept for non-engineering trained people to grasp.

Telling the people here that they need to go back to EE 101 really is beyond call; please don't resort to insults, you have _no_ idea who you are arguing with. Tell us, what is your degree? From what institution? My major was in Math (Computer Science focus) but I have a good smattering of EE, mostly on the computer side but enough to call BS when I hear it, all from the University of Waterloo.

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1. No, you are wrong. Go to TI or whatever SS component vendor of your choice, pull out a spec sheet of an Op-Amp that has completely flat frequency response from 20Hz to 20KHz for me.

The question is whether any _combination_ of components that goes into building an amplifier can produce a response such that any deviation from flat is not audible.

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Originally Posted by vitaminc View Post

It's not simply not possible without inducing a lot of abnormalities. If it's too hard for you, let me put it this way, it is NOT possible to have a transistor with flat 20Hz to 20KHz FR and perfect impulse/transient,

I suppose by perfect you're requiring infinite slope or some such nonsense? Impulse transient perfect within the passband we're concerned with (I'll even grant you an extra octave on both sides for good measure) is not such a big deal as you make it out to be, even for single transistors. By definition, within this passband, "perfect", requires only that a 40kHz sine wave passes unaltered (you do understand Fourier analysis?).

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Originally Posted by vitaminc View Post

thus it is not possible to have a silicon chip to have the such properties,

Not sure why you drag in a silicon chip? I think the subject here is the overall performance of audio amplifiers. In amplifiers (as with most consumer electronics) the limiting factor is not the performance of the individual components.

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thus it is not possible to have an amplifier with such properties, thus it is not possible to have a sound system to have such properties without adding some artifacts to compensate.

This is nonsense. First of all your conclusion does not follow from your assumptions. Second, what kind of "artifacts" are you talking about? How on earth would they compensate for non-flat FR or imperfect transient response?

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2. The bibliographies refers to stereophile and hifi-news, making the article as trustworthy as those snake-oil advertisements. Further, there's no mathematical models or simulation results. Those cut-and-paste schematics are pretty worthless anyway.

You may want to go back and read the article again, you apparently missed the fact that the reference to Stereophile was because the referenced item is an example that the article is debunking? I take it from your response you've never run a null test? Did you not recognize any of the names in that article? Are you familiar with the term AES? Do you not know any of the history behind the null test? What Hafler did with the null test is rather famous in audiophile circles and should at least ring some bells if you have any audio EE at all????

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Originally Posted by vitaminc View Post

BTW, you should considering applying for an ph.d. in electrical engineering if you know how to boost a certain frequency band without tempering with the phase, transient or other component characterization factors. It's going to be a major breakthrough in system design!

What exactly do you mean by "component characterization factors" ? That's so nonsensical I don't know how to address it. Are you really suggesting that no modern amplifier can amplify "a frequency band" without _audibly_ altering phase within the passband of the amplifier? I've already covered the fact that transient response is completely and solely dependent on frequency response. You do understand that the phase response of an amplifier is also completely and solely dependent on it's frequency response?

Look, I'm really not here to pick a fight. I'm fairly new here (though I had an userid here years ago that I no longer remember) so I don't know you from Adam. Maybe you really know what you're talking about, but so far you seem to be resorting to insults, a lot of hand waving and no specifics. It's not very constructive and I see little reason to continue unless you really do want to discuss basic EE as it relates to audio equipment?
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Pick a modern, properly functioning, transistor amplifier costing between $500 and $5000. I will personally wager you $500 that you cannot pick it, with any statistical reliability, over any other amplifier of my choosing in a double blind ABX.

Agreed.

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.
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post #119 of 139 Old 03-12-2008, 07:14 PM
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Agreed.

Are you agreeing to the challenge or to the statement? I could use the extra $500.....
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post #120 of 139 Old 03-13-2008, 03:10 PM
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Here is some food for thought... http://www.stereophile.com/features/203/index.html
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