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Skeptico Saloon: An Objectivist Joint - Page 49  

post #721 of 1671
Quote:
Originally Posted by davidsh View Post
 

What measurement goal would you say should be fulfilled for you to call an amp transparent?

 

When the measurements all exceed the thresholds of human perception.

post #722 of 1671
Quote:
Originally Posted by bigshot View Post
 
Quote:
Originally Posted by davidsh View Post
 

What measurement goal would you say should be fulfilled for you to call an amp transparent?

 

When the measurements all exceed the thresholds of human perception.

Yeah, the question is what the threshold is.. I see numbers llike 0.1% distortion being thrown around, but I suppose it's pretty hard to measure IMD in music. And noise floor is a thing to itself. And again, the noise could accumulate throughout the chain.

post #723 of 1671
post #724 of 1671
Quote:
Originally Posted by KamijoIsMyHero View Post

I would go by the stock cable being the proper/good cable. Since the product is designed with the stock cable in mind, the stock cable would essentially be the right "sounding" one. If a different cable causes a headphone to sound different, then you have found the  source that is changing the sound you are hearing. Still something that sounds "better" is subjective and it is also a broad term. I suppose the objective way of checking how it affects the sound is running a frequency sweep.

I find it problematic, when I am searching for a replacement cable myself, if people give impressions on sound differences more so than actual build quality. Even worse if the manufacturer claims sound differences. I just need a no non-sense custom cable maker that focuses on build quality instead of claims in order to sell their cables.
So with that reasoning, should one assume the stock cable always is the proper cable?
post #725 of 1671
Quote:
Originally Posted by bigshot View Post
 

The Most Important Spec Sheet: The Human Ear

http://www.head-fi.org/t/645851/the-most-important-spec-sheet-the-human-ear

Thank you, that's at least something. With such figures, I suppose one can assume any well constructed amp with enough power should be able to be audibly transparent in an ABX test, which is what you said all along, though there are still some variables like IMD that likely mean nothing in practice anyway.

post #726 of 1671

Audiophiles who keep the specs of their equipment beyond the perceptual thresholds but not ridiculously so get the exact same sound quality as those who go to absurd extremes to split the atom. Why spend a lot of money on sound you can't hear?

post #727 of 1671
Quote:
Originally Posted by miceblue View Post


So with that reasoning, should one assume the stock cable always is the proper cable?

That's is how I would go about it. The opening sentence of my post even says so. The next couple sentences is basically me saying what is the flaw in the quote "cables are cables unless one is severely flawed." Then with the "cables are cables" part, it explains how you can recreate said proper cable without much worry. Put the two together and that explains the logic, at least how I go about buying cables.

post #728 of 1671

You know about IMD, usually amps have equal or better THD numbers to IMD.  IMD products are more audible at any given level as they aren't harmonically related to the fundamental, and they are a tougher thing for amps to deal with.  Most often if your IMD is good you don't have to worry about other issues of distortion.  Also IMD tests of two tones stress the device under test more than most other test tones.  Despite many imagining otherwise, multi-tone IMD is not harder on an amp to reproduce than twin-tone IMD.  Music having many multiple tones is easier still.  Bottom line if you can get IMD results down to very low levels of .1% or less you don't have much non-linearity to worry about.

post #729 of 1671
Quote:
Originally Posted by esldude View Post
 

You know about IMD, usually amps have equal or better THD numbers to IMD.

 

IMD is usually measured with low (like 60 Hz) or very high (for example, 19 and 20 kHz) frequencies that are more challenging to the amplifier than the 1 kHz tone that is typically used for measuring THD; that is why it often looks worse in amplifier specifications. However, a similar increase at low and/or high frequencies will likely also be shown by a full 20 Hz to 20 kHz THD sweep with enough bandwidth for measuring the distortion at 20 kHz.


Edited by stv014 - 5/20/14 at 6:20am
post #730 of 1671

A quick question
In another post, the JND for jitter is said to be 20ns.
ODAC designer He-who--must-not-be-named measured jitter with a FFT method and gave dB as the unit. Do I still use the"  < - 80dB - is - not - audible"  rule with that or is it a totally different thing we are talking about?

post #731 of 1671
Quote:
Originally Posted by anthk View Post
 

Do I still use the"  < - 80dB - is - not - audible"  rule with that or is it a totally different thing we are talking about?

 

It is a reasonable "rule of thumb" for jitter as well. Actually, with sinusoid jitter at 11025 Hz, the sidebands have a total power (RMS) of -80 dBr at 4 ns peak to peak jitter level, so it is even a more pessimistic threshold than ">20 ns is audible", but by less than an order of magnitude.

post #732 of 1671

don't know if I'm allowed to post a link as there are a lot of copyright interweb fun, but there is a 5mn stuff from samantha bee on the daily show from June 2 2014 (with de niro), about vaccination. if it's available in your country (or if you're a google hacker), I recommend it. don't mind the pseudo politic attacks, just the arguments felt appallingly familiar to me. and if people are ok with ignoring facts when they concern their own lives or their children's, how are we not fighting a lost battle here in sound science?

 

my personnal favorite part : "it's a concensus of ... of who?" :deadhorse:

post #733 of 1671
Quote:
Originally Posted by castleofargh View Post
 

don't know if I'm allowed to post a link as there are a lot of copyright interweb fun, but there is a 5mn stuff from samantha bee on the daily show from June 2 2014 (with de niro), about vaccination. if it's available in your country (or if you're a google hacker), I recommend it. don't mind the pseudo politic attacks, just the arguments felt appallingly familiar to me. and if people are ok with ignoring facts when they concern their own lives or their children's, how are we not fighting a lost battle here in sound science?

 

my personnal favorite part : "it's a concensus of ... of who?" :deadhorse:


Yes, I saw that, and it quite funny.  At least until you realize what you are watching at which point it can get unsettling to say the least. 

 

Agreed, if you can't use science to save children's lives (at least with some people) what chance do we have with the audiophile cable myth.   Of course it can get worse.  I heard a Mom once, after being told she was allowing something dumb by her two boys, something which endangered their lives, "nobody says we have to do the smart thing.  We can be dumb if we want to?"

post #734 of 1671
Quote:
Originally Posted by esldude View Post
 


Yes, I saw that, and it quite funny.  At least until you realize what you are watching at which point it can get unsettling to say the least. 

 

Agreed, if you can't use science to save children's lives (at least with some people) what chance do we have with the audiophile cable myth.   Of course it can get worse.  I heard a Mom once, after being told she was allowing something dumb by her two boys, something which endangered their lives, "nobody says we have to do the smart thing.  We can be dumb if we want to?"


Natural selection will work that out for us. It's fine.

post #735 of 1671
Serious question: does burn-in produce an audible effect in some solid state amps?

I took an electrical engineering course this quarter regarding sensors and thermistors was one of the topics. I'm not an EE student, but sensors have always been kind of an interest for me and it was interesting to learn a bit more about resistors. I've seen it mentioned elsewhere but my professor said resistors are usually the noisiest components in a circuit and their performance is temperature-dependent. I'm guessing most resistors operate linearly in a specific temperature range, but their resistance changes nonetheless. Do you think some solid state amps perform differently after the device has been running for some time and the temperature of the amp remains at a stable value? I'm wondering if this is the case for Class A amplifiers since they're so inefficient and they tend to warm up quite a bit.
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