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Testing audiophile claims and myths - Page 144

post #2146 of 3264
Quote:
They won't act like passive radiators, instead they act like Helmholz resonators and will absorb sound about their resonant frequency.

 

Please explain why its not a passive radiator? Why would it absorb at the resonant frequency? Just trying to understand.

post #2147 of 3264
A passive radiator is sealed into the same cabinet as the driver. When the excursion of the driver goes out, the slight vacuum created by the movement pulls the radiator in. By adjusting the mass of the radiator, you can tune the response of the driver.

Just sitting there in the same room isn't sharing a sealed space. There's no push/pull going on. All it can do is vibrate with the sound the way anything else in the room would vibrate. A non-operating speaker in the room with a functioning one would have no impact at all on the sound of the system.
post #2148 of 3264

Oh okay, I assumed that because the cone has a resonant frequency that if the main speakers reached this frequency the cone of the sub would augment it.

post #2149 of 3264
What kind of db would be needed to move a voice coil acoustically to it's amplifying frequency?
post #2150 of 3264
I've done experiments similar to that with the walls of my listening room.
post #2151 of 3264

I find myself puzzled by the whole blind testing issue. As a scientist, I certainly believe in the value of double-blind testing. I am very much aware that our expectation color our experience. If you're told some amp costs $30K, you are likely to say it sounds better than one that costs $3K.

 

On the other hand, so many of the "scientific" types seem to take great joy in "debunking" that any differences exist in cables, tweaks, etc. Differences in cables are often not at all subtle. I have spent large amounts buying expensive cables because they obviously sound better--to me, to my wife, to my friends.

 

ABX tests often give you a few seconds of music to listen to. Some differences between gear only emerge over time. One system may let you sink into the music--feel relaxed and enjoy it. Another system may sound very accurate, yet leave you feeling edgy, strung up, uncomfortable. It takes a bit of time for these differences to emerge.

 

Also, different kinds of music show different results. Some music with lots of deep bass will show off one feature of a system that another tune with high violin notes doesn't--and vice versa. The British term PRAT--for 'pace, rhythm and tempo'--defines another characteristic that takes some listening to recognize. But we live with our gear for a long time. That's why reviewers spend typically some months with a piece of gear before writing an article about it.

 

It's true that some "golden ears" tend to ardently reject blind listening tests. The problem is often, as has been perhaps made clearer, that the wrong thing is being tested for. I would be grateful if there were more a spirit of collaboration and curiosity and interest and less stridency between the two camps.
 

post #2152 of 3264

So what's really the criticism? Some kind of ABX or otherwise controlled listening test need not rely on short samples. Usually different kinds of music samples are used, and sometimes it's test tones or noise because those allow for easier identification than music for a lot of artifacts or distortions. That said...

 

With respect to getting used to the sound, the argument doesn't really seem to hold up in light of all the overwhelming results of psychoacoustics research. The ability to distinguish things reliably gets a lot worse if there is a greater amount of time. Doing relatively short and quick comparisons yields the highest statistical power.

 

When you talk of the wrong thing potentially being tested for, is that with respect to electrical or acoustic measurements, or the listening tests? Just to be clear, are you suggesting that you have conscious preferences based on differences in sound generated? I'd say that a (legitimate) preference has to be based on recognition of differences, and hence a test for the statistically significant ability to recognize differences is what we're interested in for starters (if this is confirmed, we can move on to reasons for preference). Or are you suggesting that long-term exposure leads to some kind of physiological or subconsciously understood difference, but that people can't consciously figure out which is which and thus are affected but can't be expected to pass a relatively short-term blinded listening test?

 

I don't know about taking joy in debunking, but part of the reason for skepticism has to do with the magnitude of changes we're talking about and then also the non-blinded subjective assessments that are being attributed to some things. If you look at the cause and effect of what causes something to be perceived, nothing really seems to add up anywhere unless you take the angle of "despite peoples' best efforts, nobody has yet found mystery factor ______".

post #2153 of 3264
Quote:
Originally Posted by wahhabb View Post

On the other hand, so many of the "scientific" types seem to take great joy in "debunking" that any differences exist in cables, tweaks, etc. Differences in cables are often not at all subtle. I have spent large amounts buying expensive cables because they obviously sound better--to me, to my wife, to my friends.

 

Fine. But knowing what we know about human psychology as it relates to our subjective perceptions, until that is controlled for, such anecdotes don't really inform beyond what works subjectively for a particular individual.

 

Quote:
ABX tests often give you a few seconds of music to listen to. Some differences between gear only emerge over time. One system may let you sink into the music--feel relaxed and enjoy it. Another system may sound very accurate, yet leave you feeling edgy, strung up, uncomfortable. It takes a bit of time for these differences to emerge.

 

There's nothing inherent about ABX testing that mandates you only have a few seconds of music to listen to and I'm not sure where this is coming from, but I see it thrown out as a common "criticism" of ABX testing.

 

And FYI, some years ago Tom Nousaine set up ABX comparators in a number of peoples' homes so they could do the testing at their leisure. Listen for as long as they want whenever they want. However nothing ever turned up.

 

Quote:
Also, different kinds of music show different results. Some music with lots of deep bass will show off one feature of a system that another tune with high violin notes doesn't--and vice versa. The British term PRAT--for 'pace, rhythm and tempo'--defines another characteristic that takes some listening to recognize. But we live with our gear for a long time. That's why reviewers spend typically some months with a piece of gear before writing an article about it.

 

See above.

 

Quote:
It's true that some "golden ears" tend to ardently reject blind listening tests. The problem is often, as has been perhaps made clearer, that the wrong thing is being tested for. I would be grateful if there were more a spirit of collaboration and curiosity and interest and less stridency between the two camps.

 

Well, the "golden ears" have had over 30 years to "do it right" and demonstrate once and for all the audible differences they've been claiming over those decades. But so far that hasn't happened, in spite of the fact that it would be a total game changer for the industry.

 

So I'll end this by saying "We're still waiting."

 

se

post #2154 of 3264

I used to read articles that claimed that all that mattered about audio gear was whether it produced a flat frequency response curve. It's obvious now that much more is required. For example, transient response is critical to creating the sound of an instrument. Other features, like very low noise levels, play a big role in spatial orientation of sounds and other features. So this is an example of the failure to measure important items.

 

I haven't carefully reviewed all of the tests that have been made, so I can't claim expertise about that. What I can say with confidence is that some of the sonic differences between gear that supposedly "people can't hear the difference between" are so blatantly obvious when you actually listen, that any test that says people can't tell the difference simply has to be an invalid test.

 

It is true that some people have tin ears. I have read that in abx testing of MP3's vs. CD type 44-16 sound, many people could not hear the difference at more than a chance result. However, in further testing, some people could tell the difference with absolute consistency.
 

post #2155 of 3264
Quote:
Originally Posted by wahhabb View Post

I certainly believe in the value of double-blind testing.

Differences in cables are often not at all subtle. I have spent large amounts buying expensive cables because they obviously sound better--to me, to my wife, to my friends.

ABX tests often give you a few seconds of music to listen to.

 

The solution is easy. Do a long DB test. Find out if you really are hearing what you think you're hearing. I bet I know what you'd find out!

post #2156 of 3264
Quote:
Originally Posted by wahhabb View Post

I used to read articles that claimed that all that mattered about audio gear was whether it produced a flat frequency response curve. It's obvious now that much more is required. For example, transient response is critical to creating the sound of an instrument.

 

The transient response of musical instruments is MUCH slower than the transient response of reasonably good transducers. Frequency response IS the key. It isn't easy to achieve a flat response. Most people aren't able to adjust it for themselves. Get yourself a nice flat response, and THEN decide whether FR doesn't matter.

post #2157 of 3264
Quote:
Originally Posted by wahhabb View Post

I used to read articles that claimed that all that mattered about audio gear was whether it produced a flat frequency response curve. It's obvious now that much more is required. For example, transient response is critical to creating the sound of an instrument. Other features, like very low noise levels, play a big role in spatial orientation of sounds and other features. So this is an example of the failure to measure important items.

 

I don't know what articles you're referring to specifically, but if you're reading articles that are making such simpleminded claims, you need to stop reading those articles and expand your horizons a bit. If you have a library nearby that has a decent reference section, I might suggest reading through some issues of the JAES (Journal of the Audio Engineering Society).

 

Quote:
What I can say with confidence is that some of the sonic differences between gear that supposedly "people can't hear the difference between" are so blatantly obvious when you actually listen, that any test that says people can't tell the difference simply has to be an invalid test.

 

Since you haven't demonstrated actual audible differences, you start from a false premise.

 

You need to realize that subjectively perceived differences that are the result of nothing more than our own psychology seem no less "real" than those due to actual audible differences.

 

Quote:
It is true that some people have tin ears. I have read that in abx testing of MP3's vs. CD type 44-16 sound, many people could not hear the difference at more than a chance result. However, in further testing, some people could tell the difference with absolute consistency.

 

Not even the person who developed MP3 has ever claimed that there are no audible differences between MP3 and lossless. So not sure what your point is here.

 

se

post #2158 of 3264
Quote:
Originally Posted by bigshot View Post

 

The transient response of musical instruments is MUCH slower than the transient response of reasonably good transducers.

 

But no one's claiming there are no audible differences between transducers. That's the one area there's no disagreement about.

 

se

post #2159 of 3264
Most of the differences are in frequency response. And the transient response of electronics is going to be so tight, it would be inaudible.
Edited by bigshot - 8/6/13 at 11:14pm
post #2160 of 3264
Quote:
Originally Posted by bigshot View Post

Most of the differences are in frequency response.

Doesn't change my point.

se
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