"Official" All amps sound the same thread - Page 6 - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #151 of 2642 Old 02-03-2009, 06:28 PM
AVS Special Member
 
mcnarus's Avatar
 
Join Date: Nov 2007
Posts: 6,012
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 266
Quote:


I have done many blind tests in my life. Level matching gets a bit tricky, but we tried our best. I guess I did it for fun? Any other reason why I should have done it?

Well, you seem to want to make unsupported claims on Internet forums. If you had done a real, level-matched comparison, then your claims would actually have been supported!

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

mcnarus is online now  
Sponsored Links
Advertisement
 
post #152 of 2642 Old 02-03-2009, 06:42 PM
AVS Special Member
 
Knucklehead90's Avatar
 
Join Date: Nov 2008
Location: State of Confusion - 98823
Posts: 7,334
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Liked: 98
Quote:
Originally Posted by MichaelJHuman View Post

All I know is that air temp affects propagation. If I am not mistaken, sound propagates better in colder air.

It would be interesting to know if there are factors related to air properties which affect frequency response.

*
Because cooler air usually contains more moisture - humidity - sound does travel better in cool air. Another factor is the density, at higher elevations the thin air acts as a dampener on sound. Not likely that you will be able to ascertain the differences in your LR unless you live at 15K feet. You may be more concerned with breathing than listening.

When all else fails - RTFM!

♫♫♫ Two Channel Rules! ♫♫♫

GO SEAHAWKS!!!
Knucklehead90 is online now  
post #153 of 2642 Old 02-03-2009, 07:01 PM
Member
 
ericm83's Avatar
 
Join Date: Nov 2006
Posts: 135
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Knucklehead90 View Post

*
Because cooler air usually contains more moisture - humidity - sound does travel better in cool air. Another factor is the density, at higher elevations the thin air acts as a dampener on sound. Not likely that you will be able to ascertain the differences in your LR unless you live at 15K feet. You may be more concerned with breathing than listening.

Well actually the higher the humidity the less dense the air and so sound will not propagate as well. I know it seems counter intuitive, but its true. You are right though that cold air does transmit sound better, it just isn't because of humidity. In cold air the particles aren't moving around as fast so they can pack in tighter.

I agree though, I don't think it would really matter when we are talking about home theater.


ericm83 is offline  
post #154 of 2642 Old 02-03-2009, 07:48 PM
Member
 
czachorski's Avatar
 
Join Date: Jan 2009
Posts: 21
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by mcnarus View Post

And have you ever once done a blind, level-matched comparison of any of them?

I would be interested in reviewing the results of tests that support your claim.
czachorski is offline  
post #155 of 2642 Old 02-03-2009, 08:59 PM
AVS Special Member
 
krabapple's Avatar
 
Join Date: Apr 2003
Location: in a state bordered by Kentucky and Maine
Posts: 5,236
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 145
Quote:
Originally Posted by steve71 View Post

The definition of worse and/or the sub (other than impedance) in this case is irrelevant since the argument is all amps sound the same.

FAIL.

That isn't the argument.

Quote:


In other words since the sub sounds fine running off a single channel, then (since all amps sound the same), the crown should sound identical in bridged mode right?


Here's perhaps a more fundamental question: since sighted listening is fraught with chances for error, why should we accept at face value your sighed comparison testimony that the two states sound different, much less that one sounds worse?

But if you can hear a difference, it is measureable. Why don;t you follow Chu's advice and ask Crown why your amp/speaker combo might be distorting audibly in one state but not the other?
krabapple is online now  
post #156 of 2642 Old 02-03-2009, 09:11 PM
AVS Special Member
 
krabapple's Avatar
 
Join Date: Apr 2003
Location: in a state bordered by Kentucky and Maine
Posts: 5,236
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 145
Quote:
Originally Posted by RWetmore View Post

I asked this very question to our friend Kurt from Blue Jeans Cable.

Audio cable manufacturers, other than the folks from Belden, are not typically the 'go to' for straight talk on audio difference, much less difference between amps.

Quote:


Here is his very detailed and informative reply:

Be still my beating heart. Jjust for giggles, in what form did you pose the question to him? Did you ask 'Do amps ever sound different?' or was it a question that WASN'T a strawman?

Quote:


"Yes, absolutely, it's possible for similarly-spec'd amplifiers to sound
different from one another. This is very different from, say, expecting
cables to sound particularly different from one another; amplifiers are
active circuits; they have circuit impedances that vary with frequency,
filtering circuits which modify signals incoming, outgoing, and in process,
and semiconductors (or tubes) that have different noise floors, gain
characteristics, et cetera.

"et cetera." Let's see some data that those differences are ROUTINELY above audible threshold.

Quote:


This is a bit like designing a camera lens:
there's no simple, straightforward design that combines the best of all
possible outcomes, and so every design is something of a compromise between
competing objectives. The ideal amplifier is perfectly linear within its
operating frequency range, causes no distortion, cuts off sharply outside
its intended frequency band, and presents all of these characteristics
regardless of the type or level of input signal and the amount of gain
required--but this ideal amplifier is an idea, not a reality, and real-world
devices can and do differ in meaningful, audible ways, even as they attempt
to realize that ideal.

And this is a ******** argument, because amps don't have to be 'perfectly linear' to be audibly indistinguishable, and a difference can be 'meaningful' in objective terms (if, for example, a certain design target is to be met) but be irrelevant in audible terms. What's required is that their linear and nonlinear distortions remain below thresholds of audibility.


Quote:


Now, it's also probably fair to say that there is a lot of overstatement,
and some misconceptions, that people engage in when DESCRIBING the
differences between amps. Two good amps, both fed the same material and
driving the same speakers, ought to both sound good; but they may sound
different from one another, within a limited range.

Under what conditiosn, pray tell?

Quote:


Obviously, if they
really sound profoundly different from one another, something is probably
the matter with one or both of them. We run into this in audiophile stuff
from time to time; for example, tube amps will often be said to be "warmer"
than transistor amps. That's true if one takes a certain view of what
"warmer" means; tube amps typically soften the highs a bit and that causes a
presentation which people often describe as warm. But that "warmth" comes,
of course, at the price of accuracy of reproduction of the input signal.
Whether one likes it or not is, of course, another matter.

Thanks,

Kurt
BJC"

Gee, that's nice, but no one is arguing about tube vs SS amps


Quote:


I agree with Kurt as his explanation is the most consistent with my own listening experiences.

Instead of bothering people like 'our friend Kurt', how about reading the E. Brad Meyer article I linked to? It laid out the potential causes of difference in layman's terms quite nicely, some 20 years or so ago.
krabapple is online now  
post #157 of 2642 Old 02-03-2009, 10:19 PM
AVS Special Member
 
moonhawk's Avatar
 
Join Date: Jun 2003
Location: La Madera, New Mexico
Posts: 3,188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 34
Quote:
Originally Posted by MichaelJHuman View Post

Can the dynamics be limited when clipping is not occuring?

I understand that if you drive a speaker too hard, it's output will be limited by its range of excursion. The dynamic range of say the woofer, may be limited compared to the tweeter, resulting in a form of compression, and a loss of overall balance.

______________________

__________

Dave

moonhawk is offline  
post #158 of 2642 Old 02-03-2009, 10:37 PM
AVS Special Member
 
moonhawk's Avatar
 
Join Date: Jun 2003
Location: La Madera, New Mexico
Posts: 3,188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 34
Quote:
Originally Posted by Ryan Peddle View Post

The fact of the matter is, it is impossible to get a completely perfect linear response from 20 to 20k. And by perfect I mean ____________________.

Hell my hearing tapers off at 16K. So wouldn't that play a part. I mean for a person to truly judge if there is a difference, they would have to go to an audiologist and be tested to find out if, and in more cases than you think, where you hearing is deficient.

I'm sure mine does, too, as well as many others here. But remember, 16K to 20K is only a fraction of an octave of very subtle -- though of course important-- sound.

Do re mi fa so la ti do--the musical scale of one octave. If lower "do" is 10K, then 16K is probably between "so" and "la". upper "do" is 20K, as each octave doubles or halves the grequency.I don't know the exact math here, anybody jump in if you can correct me.

But my point is loss at 16K is probably not the end of the wor
ld musically, though of course all the way to 20 would be preferable. Just a little optimistic perspective for those of us who ain't getting any younger.

______________________

__________

Dave

moonhawk is offline  
post #159 of 2642 Old 02-03-2009, 11:02 PM
AVS Special Member
 
moonhawk's Avatar
 
Join Date: Jun 2003
Location: La Madera, New Mexico
Posts: 3,188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 34
Quote:
Originally Posted by phantom52 View Post

I have had the opportunity to compare 2 separate amps using an AVR as a pre-pro and I definately could tell the difference in the sound. One was an Anthem, the other was the Parasound.

So which did you prefer?

(Bear with me please, if this has already been asked--just found this thread and I'm still on page 3).

______________________

__________

Dave

moonhawk is offline  
post #160 of 2642 Old 02-04-2009, 05:24 AM
AVS Special Member
 
Easyaspie's Avatar
 
Join Date: Mar 2008
Posts: 2,310
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
Quote:
Originally Posted by mcnarus View Post

Since you can write, I have to assume you can read. So read post #122.


Yes, but so what? If you're twiddling with the volume knob, you're never gonna know. See, again, post #122.


The people who say he added distortion of some sort are the people who know what they're talking about. That is the only way it would be possible. See, yet again, post #122.

So I'm guessing your answer is no.
Easyaspie is offline  
post #161 of 2642 Old 02-04-2009, 06:10 AM
AVS Special Member
 
mcnarus's Avatar
 
Join Date: Nov 2007
Posts: 6,012
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 266
Quote:


I would be interested in reviewing the results of tests that support your claim.

The best summary I can point you to is Tom Nousaine's old review of amp tests. Here's his conclusion:

Quote:


In summary, there has been no evidence to support the conclusion that factors other than linear response and output capability contribute to the sound of well designed power amplifiers...

This does not suggest that amplifiers are perfect and they will never be found to sound different. It does suggest to purchasers of today's audio amplifiers that as long as the product in question meets basic traditional measured performance standards, has enough output capability, and adequate quality of construction, it will be sonically indistinguishable from all others meeting those criteria.


See also the Meyer article that Krabapple linked to earlier.

And if you doubt that people really hear differences where none exist, Nousaine did a paper on that, too.

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

mcnarus is online now  
post #162 of 2642 Old 02-04-2009, 06:11 AM
AVS Special Member
 
mcnarus's Avatar
 
Join Date: Nov 2007
Posts: 6,012
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 266
Quote:


So I'm guessing your answer is no.

I dunno. What was the question?

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

mcnarus is online now  
post #163 of 2642 Old 02-04-2009, 06:56 AM
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked: 414
Quote:
Originally Posted by krabapple View Post

But if you can hear a difference, it is measureable. Why don;t you follow Chu's advice and ask Crown why your amp/speaker combo might be distorting audibly in one state but not the other?

Well, we (not Steve) don't know what this 'worse' was when the amp was run bridged. Personally I suspect Steve did notice a problem. Crown might ask for clarification of the term worse, the measured impedance of the sub, crossover questions, etc. For all I know, distortion/noise rises appreciably when bridged and may further rise or go into some sort of oscillation if the impedance over the frequency range drops. But, that's pure speculation on my part. To not avail yourself of a free phone call to get some insight from the actual manufacturer and have the ability to speak to engineers, that just doesn't make sense to me.

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #164 of 2642 Old 02-04-2009, 07:18 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 13,852
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 405 Post(s)
Liked: 1049
Quote:
Originally Posted by MichaelJHuman View Post

As mentioned, there's a number of people who don't feel blind testing tells the whole story.

There are lots of people who have a vested interest in not believing anything in particular. This can cut both ways.

However, there seem to be far more people who have a vested interest in believing that the last purchase they made was fully justified by sound quality. And then there are the purchases they made before that.

Furthermore, there are many reasons why equipment comparisons will come out as being positive for audible differences, listener bias notwithstanding. Poor level matching is probably the most common.
arnyk is online now  
post #165 of 2642 Old 02-04-2009, 07:24 AM
AVS Special Member
 
Easyaspie's Avatar
 
Join Date: Mar 2008
Posts: 2,310
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
Quote:
Originally Posted by mcnarus View Post

I dunno. What was the question?

See post #125.
Easyaspie is offline  
post #166 of 2642 Old 02-04-2009, 07:28 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 13,852
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 405 Post(s)
Liked: 1049
Quote:
Originally Posted by vpopovic View Post

I simply can't resist to suggest position 5: Amps simply are different in design, built, looks, and but of course the way they sound. To briefly support the statement, over the years, I had at least 2 tons of amplifiers (by weight) in my systems for longer period of time, which probably means at least additional 2 tons on trial. My back remembers most of them, my ears some of them. They all are different, not just by weight, but in the way they sound.

Nice tacit admission that you have a strong vested interest in the idea that all amps sound different. If they didn't, you have wasted a lot of time and money.
arnyk is online now  
post #167 of 2642 Old 02-04-2009, 07:33 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 13,852
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 405 Post(s)
Liked: 1049
Quote:
Originally Posted by steve71 View Post

BTW the signal was level matched with a 60hz sine wave at approx 3 volts across the amp terminals under load.

60 Hz is a pretty strange choice of single frequency to match levels. Most technically savvy people would pick 1 KHz or 400 Hz. Furhtermore, matching levels at just one frequency leaves the doors open for a ton of level match differences due to frequency response.


Quote:


There is no need to DBT when something is as plain as the nose on your face.

That statement has been made and debunked a great many times. The same argument has been made for CD pens. Do you want to go there?

Quote:


Why would anyone wish their amp to sound worse bridged?

More to the point, why should an amp sound worse bridged unless it was incompent when driving low impedance loads?

If it an amp is incompetent to drive a low impedance load then the most common symptom would be clipping, and that is one of the conditions that it has been said again and again to cause audible differences.
arnyk is online now  
post #168 of 2642 Old 02-04-2009, 07:39 AM
AVS Special Member
 
mcnarus's Avatar
 
Join Date: Nov 2007
Posts: 6,012
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 266
Quote:


See post #125.

The only question I see in post #125 (unless you want to know if I remember Bob Carver) is this one:
Quote:


Do you have any examples of people actually doing this, or do you just assume they must because there is no way for an amp to sound different?

There are multiple posts in this very thread where people describe doing exactly what I referred to. They're my examples. Also, if you'd actually comprehended anything I've written here, you would know that I do not believe that "there is no way for an amp to sound different."

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

mcnarus is online now  
post #169 of 2642 Old 02-04-2009, 07:53 AM
Senior Member
 
humbug2's Avatar
 
Join Date: Oct 2006
Location: Farmington Hills MI
Posts: 291
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked: 15
Personal opinions and experiences:
1. There may be several forms of sound distortion that are not currently measured, or even formally recognized.

2. On prejudices and expectations: I have heard many different examples of all audio product types and my judgments were not as expected, nor consonant with reviews I had read prior to experiencing.

3. In comparing products memory is not a factor if you write down your impressions at the time and compare them.

4. You are a major variable. The same record on the same system can be very annoying after a bad day, or conversely transcendant when relaxing late at night after a bad day.

5. For me, emotional response to the music is far more important than any measurement. The best equipment ($$,$$$ per piece) does it, the rest not nearly as much. Unfortunately I live with the rest ($,$$$ per piece).

6. In my system humidity has a very noticable effect on the sound of a system. If high (summer, > 60% or so) the sound is dull, lifeless as compared to usual 40% or so. Temperature is fairly constant year around. This has to be taken into consideration when judging a products overall performance.

7. Since I don't normally listen in a blind environment I really don't care about such.

"Most people would die sooner than think, in fact they do so."  Bertrand Russell The ABC of Relativity, 1925

humbug2 is offline  
post #170 of 2642 Old 02-04-2009, 08:23 AM
AVS Special Member
 
steve71's Avatar
 
Join Date: Nov 2006
Posts: 1,191
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
Quote:
Originally Posted by Chu Gai View Post

Well, we (not Steve) don't know what this 'worse' was when the amp was run bridged. Personally I suspect Steve did notice a problem. Crown might ask for clarification of the term worse, the measured impedance of the sub, crossover questions, etc. For all I know, distortion/noise rises appreciably when bridged and may further rise or go into some sort of oscillation if the impedance over the frequency range drops. But, that's pure speculation on my part. To not avail yourself of a free phone call to get some insight from the actual manufacturer and have the ability to speak to engineers, that just doesn't make sense to me.

When bridged there is a lack of control over the low frequencies (below around 35hz). It's a mute point for two reasons, firstly because a single channel from the crown is more than enough power for all but ear damaging, lets see how loud this thing will go testing. Secondly I'm now using a BGW 750C amp bridged to power the sub. It's a 55lb class a/b mid 80's beast that is still going strong (750 watts into 8ohms bridged). Touch wood it doesn't fail and send DC to my VC any time soon .

edit: measured impedance of the driver is here - nothing below 5.8 ohms

http://www.bcspeakers.com/PDF/PRD/15PS100.pdf
steve71 is offline  
post #171 of 2642 Old 02-04-2009, 08:34 AM
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked: 414
Arny, I think he ran 60Hz because it was a sub.

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #172 of 2642 Old 02-04-2009, 08:44 AM
AVS Special Member
 
steve71's Avatar
 
Join Date: Nov 2006
Posts: 1,191
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
I used 60hz because I was too lazy to bypass my AVP's crossover. I used my laptop and REQ as a signal generator. If it's level matched at 60hz it's level match everywhere - unless of course bridging the amp alters the FR.

DBT is not the be all end all. A DBT could be devised to prove or disprove a difference by being selective with program material and subjects. If you do manage to achieve a positive correlation of 80% or greater with a DBT then you've proven something! But on the other hand if you get less than 80% then you may have just proven than you picked the wrong set of test conditions.

The crown is rated to 1140watts (yeah right!) into 4 ohms in a bridged configuration. The clipping LED's did not come on.


Quote:
Originally Posted by arnyk View Post

60 Hz is a pretty strange choice of single frequency to match levels. Most technically savvy people would pick 1 KHz or 400 Hz. Furhtermore, matching levels at just one frequency leaves the doors open for a ton of level match differences due to frequency response.




That statement has been made and debunked a great many times. The same argument has been made for CD pens. Do you want to go there?



More to the point, why should an amp sound worse bridged unless it was incompent when driving low impedance loads?

If it an amp is incompetent to drive a low impedance load then the most common symptom would be clipping, and that is one of the conditions that it has been said again and again to cause audible differences.

steve71 is offline  
post #173 of 2642 Old 02-04-2009, 09:14 AM
AVS Special Member
 
mcnarus's Avatar
 
Join Date: Nov 2007
Posts: 6,012
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 266
Quote:


But on the other hand if you get less than 80% then you may have just proven than you picked the wrong set of test conditions.

But that's still more than you've proved by doing a sighted comparison.

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

mcnarus is online now  
post #174 of 2642 Old 02-04-2009, 09:24 AM
AVS Special Member
 
krabapple's Avatar
 
Join Date: Apr 2003
Location: in a state bordered by Kentucky and Maine
Posts: 5,236
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 145
Quote:
Originally Posted by humbug2 View Post

Personal opinions and experiences:
1. There may be several forms of sound distortion that are not currently measured, or even formally recognized.


Unicorns may exist too. But if you propose them as an explanation for something, it's your job to provide the evidence. And 'I heard it' isn't good enough, unless you run standard controls; we *already* have explanations for why you can 'hear' the audio equivalent of a unicorn. You need to rule THOSE explanations out, first, before putting any weight on novel distortions.

Quote:


2. On prejudices and expectations: I have heard many different examples of all audio product types and my judgments were not as expected, nor consonant with reviews I had read prior to experiencing.

Biases need not be conscious.

Quote:


3. In comparing products memory is not a factor if you write down your impressions at the time and compare them.

Limitations of audio memory remains a factor in any comparison, whether the impressions are written down or not. These limitations suggest the use of quick switching protocols to optimize your powers of discrimination. Without it, the written record can simply end up as an example of GIGO -- garbage in, garbage out


Quote:


4. You are a major variable. The same record on the same system can be very annoying after a bad day, or conversely transcendant when relaxing late at night after a bad day.

True. Which should give audiophiles pause before they confidently assert that the difference they heard was because they changed the *gear*.

Quote:


5. For me, emotional response to the music is far more important than any measurement. The best equipment ($$,$$$ per piece) does it, the rest not nearly as much. Unfortunately I live with the rest ($,$$$ per piece).

If that's so, wanna bet some of that 'emotional response' isn't coming from the *music* at all?

Quote:


6. In my system humidity has a very noticable effect on the sound of a system. If high (summer, > 60% or so) the sound is dull, lifeless as compared to usual 40% or so. Temperature is fairly constant year around. This has to be taken into consideration when judging a products overall performance.

Consider also your physiological state in humid weather.

Quote:


7. Since I don't normally listen in a blind environment I really don't care about such.

Which is basically saying, you don't care if something's real or not. High-end snake-oil makers LOVE guys like you.
krabapple is online now  
post #175 of 2642 Old 02-04-2009, 09:31 AM
AVS Special Member
 
krabapple's Avatar
 
Join Date: Apr 2003
Location: in a state bordered by Kentucky and Maine
Posts: 5,236
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 81 Post(s)
Liked: 145
Quote:
Originally Posted by steve71 View Post

I used 60hz because I was too lazy to bypass my AVP's crossover. I used my laptop and REQ as a signal generator. If it's level matched at 60hz it's level match everywhere - unless of course bridging the amp alters the FR.

DBT is not the be all end all. A DBT could be devised to prove or disprove a difference by being selective with program material and subjects.

Odd, then, that DBT is the method of choice for scientists.

If a DBT 'proves' the difference , then there's probably an audible difference under those conditions. A 'negative' result means that the hypothesis of difference was not supported under those conditions. Nothing more or less.

Sighted comparison, on the other hand, allows NO conclusion either way.


Quote:


If you do manage to achieve a positive correlation of 80% or greater with a DBT then you've proven something!

No, you haven't, unless you've set "80%" as your confidence level. Typically it's "95%" or better (actually it's evaluated in terms of p value, the probability that you made the *wrong* conclusion. "95%" in this instance means you accept a 5% chance of being wrong. For a difference that is a priori quite unlikely -- like, say, an audio unicorn -- one could well demand a p of < 1%).

Quote:


But on the other hand if you get less than 80% then you may have just proven than you picked the wrong set of test conditions.


Meanwhile, sighted comparison is *always* the wrong set of test conditions, scientifically speaking.
krabapple is online now  
post #176 of 2642 Old 02-04-2009, 09:46 AM
AVS Special Member
 
Easyaspie's Avatar
 
Join Date: Mar 2008
Posts: 2,310
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
Quote:
Originally Posted by mcnarus View Post

The only question I see in post #125 (unless you want to know if I remember Bob Carver) is this one:

There are multiple posts in this very thread where people describe doing exactly what I referred to. They're my examples. Also, if you'd actually comprehended anything I've written here, you would know that I do not believe that "there is no way for an amp to sound different."

Posturing I guess. Thats fine.

What I do know is that you seem to think that if an amp does sound different from another, one must be malfunctioning.

I have read several reviews by a well repected audio journalist who believes that he hears differences in amplifiers. He also hears differences in cables, even power cables. So for you and 1 or so other posters to not even be able to acknowledge that it is possible speaks volumes.

It's not so much a difference of opinion, it's you and your buddy inferring that someone who disagrees with you is either an idiot or a liar. Nice job.
Easyaspie is offline  
post #177 of 2642 Old 02-04-2009, 09:46 AM
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked: 414
Your findings then suggest that the Crown XLS 402D, when bridged, has problems with your sub. Like you said, it ought to have had no issues making the usual assumptions. The 402 has gone through several iterations and originally it wasn't spec'd for bridged 4 ohm operation. Me, I'd arrange for Crown to service it if it's under warranty.

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #178 of 2642 Old 02-04-2009, 09:54 AM
AVS Special Member
 
mcnarus's Avatar
 
Join Date: Nov 2007
Posts: 6,012
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Liked: 266
Quote:


I have read several reviews by a well repected audio journalist who believes that he hears differences in amplifiers. He also hears differences in cables, even power cables. So for you and 1 or so other posters to not even be able to acknowledge that it is possible speaks volumes.

Well respected by whom? Certainly not anybody in the scientific community, where audio "journalism" is regarded as a bad joke. Put a cloth over (most of those) things, and I guarantee you he won't be able to tell them apart to save his life. And when he can, we'll be able to point to a simple measured difference that can explain it.

Look, you want to believe in unicorns, that's your business. You want to buy magazines written by people who believe in unicorns, that's your business, too. But make no mistake: Most of the people out there writing about audio today believe in unicorns.

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

mcnarus is online now  
post #179 of 2642 Old 02-04-2009, 10:05 AM
AVS Addicted Member
 
Chu Gai's Avatar
 
Join Date: Sep 2002
Location: NYC area
Posts: 14,725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked: 414
Quote:
Originally Posted by Easyaspie View Post

Posturing I guess. Thats fine.

What I do know is that you seem to think that if an amp does sound different from another, one must be malfunctioning.

Not necessarily. Large output impedance, noise levels, one or both driven past its capabilities, instability, and more come to mind.

Quote:


I have read several reviews by a well repected audio journalist who believes that he hears differences in amplifiers. He also hears differences in cables, even power cables. So for you and 1 or so other posters to not even be able to acknowledge that it is possible speaks volumes.

I know a well respected journalist that says the same thing. He also hears differences when he turns a power distribution center upside down or on its side, when he replaces fuses, if he puts a ferrite bead on a power cord, etc. He also is practices Reiki -interaction with our energy auras by a waving of the hands - and holds periodic gatherings where he & other spiritually attuned folks focus their psychic energies to heal people. Some people you know are just nuts, but they write well.

"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House
Chu Gai is online now  
post #180 of 2642 Old 02-04-2009, 10:15 AM
AVS Special Member
 
LEVESQUE's Avatar
 
Join Date: Jul 2002
Location: Canada
Posts: 2,019
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by steve71 View Post

DBT is not the be all end all.

Tell that to the whole pharmacological industry... relying on those all the time... And try to tell that to your mom's doctor when he will need to choose the proper cancer medication to give to her...
LEVESQUE is offline  
Reply Receivers, Amps, and Processors

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off