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Testing audiophile claims and myths - Page 106

post #1576 of 3037

Hi, guys. I've been lurking Sound Science forum for some time and I think it's really great for all beginning head-fiers. I pretty much agree with any statement I've read here, but there's one question I haven't found an answer for. The Audio Critic says that (quote) "If amplifiers A and B both have flat frequency response, low noise floor, reasonably low distortion, high input impedance, low output impedance, and are not clipped, they will be indistinguishable in sound at matched levels no matter what’s inside them.". I suppose that it also applies to any solid state headphone amp. But what about the amp that can be found in the Asus Xonar Essence ST/STX sound cards? Is it also the same in terms of sound quality compared to desktop solid state amps? It's characteristics are one of the best out there (Output Signal-to-Noise Ratio is 117dB for Headphone-out (600ohms), Output THD+N at 1kHz is 0.001% (-100dB) for Headphone-out). Please help me out with this one. smily_headphones1.gif

post #1577 of 3037
Quote:
Originally Posted by Jessse View Post

But what about the amp that can be found in the Asus Xonar Essence ST/STX sound cards? Is it also the same in terms of sound quality compared to desktop solid state amps? It's characteristics are one of the best out there (Output Signal-to-Noise Ratio is 117dB for Headphone-out (600ohms), Output THD+N at 1kHz is 0.001% (-100dB) for Headphone-out). Please help me out with this one. smily_headphones1.gif

 

It should be fine for 250 Ω or higher headphones, and also many lower impedance ones, but it does have a few disadvantages that affect low impedance headphones:

- the output impedance is relatively high (slightly more than 10 Ω); this makes an audible difference with many low impedance dynamic headphones, and especially balanced armature IEMs

- the distortion is not as good as advertised when driving a low impedance load under 100 Ω (see here and here); distortion in the 0.0x% range still might not be audible in practice, though

- there may be some audible hiss with sensitive low impedance headphones and IEMs, especially when using a sample rate that is a multiple of 44100 Hz. This is because all volume and gain control on the card is digital, and the analog circuits run "wide open" at full gain all the time; also, Xonar family sound cards are noisier when the DAC has to be re-clocked to play audio at a sample rate of 44100, 88200, or 176400 Hz. There is about 20 uV or slightly less A-weighted noise floor on the headphone output at 44100 Hz (less than half of that at 48000 Hz), but this is obviously attenuated somewhat when driving a low impedance load. With Shure SE535 IEMs, for example, the A-weighted noise SPL would be ~30-31 dB, which is audible. The manufacturer's specification of 117 dB SNR is about right at the "good" sample rates and referenced to the full scale 7 Vrms output.

 

For a small number of very hard to drive headphones like the Hifiman HE-6, there may not be enough power. Also, for some people who prefer really loud (and damaging) listening levels and/or very dynamic and "quiet" music, it might not be enough for headphones like the DT880-600Ω, but the peak SPL of nearly 113 dB is likely enough for most.

post #1578 of 3037

Thanks for the detailed reply, stv104! I'm planning to use it with Sennheiser HD 600 (300Ω). Guess it should work fine on High or Extra High Gain setting. I was looking for something along the lines of Schiit Asgard, but I'd rather settle with my Xonar Essence ST now.

post #1579 of 3037

I am a little surprised that more headphones were not used to try to differentiate between the different setups.  From all of my testing the more sealed and flatter frequency response headphone almost always reveals the most about a system.  I am not saying that a custom IEM would give different results, but I am saying that it may be a better test than a setup susceptible to ambient noise and distraction.

 

Take my home setup for example.  With a pair of Denon AH-D2000 headphone running through a Grace Design m903 amp fed via USB I found it very difficult to hear differences on mp3ornot.com.  Changing the headphone to a sealed IEM gave much better results.  I think tests like mp3ornot.com are good especially if one realizes they can hear the difference with better gear.  That is the entire premise of hi-fi.  To add onto that there are folks that are starting to actually measure results which provided direct evidence of whether there are differences or not.

 

If we all used Apple ear buds for testing would we ever hear a difference where there was one?  Probably not.  There is a lot of components in the audio equation and some equipment improves the results and some degrade them.  It is not always the more expensive and hope that people out there understand that Worthington's lay is not a law of nature.  More money does not equal better than.

 

I still thank people who conduct these tests and especially those that admit that they do not hear a difference.

 

In the end I hope we all enjoy our gear and especially our music.  I hate to think about the loss of high quality sound production that raises the bar for audio engineers and recording studios.

post #1580 of 3037

Did anyone do the DBT between Sennheiser HD 600 and HD 650? Is there really big difference? 

post #1581 of 3037

I found the 650 to sound muffled and bloated in comparison, but I admit, it was not a blind test of any sort.

post #1582 of 3037

After reading countless reviews I'm leaning towards HD600 too, but I realise that these reviews are far from being objective.


Edited by Jessse - 10/30/12 at 9:01am
post #1583 of 3037

I don't know if there are any EE's posting here, but take a look at this article :

 

http://audiophilereview.com/cables/why-speaker-cables-are-more-than-you-think-they-are.html

 

Any glaring issues in this article?

post #1584 of 3037

Damping factor's a bit overrated.

 

Dick Pierce (yeah, I know) had a good article on this in the June 1997 issue of Speaker Builder magazine.

 

se

post #1585 of 3037
Quote:
Originally Posted by Yahzi View Post

I don't know if there are any EE's posting here, but take a look at this article :

 

http://audiophilereview.com/cables/why-speaker-cables-are-more-than-you-think-they-are.html

 

Any glaring issues in this article?

 

That's a pretty simple treatment, only focusing on the resistance of the entire length of cable and its effect on damping factor.  That said, this is the biggest issue with cables for audio (one of the only that's ever a legitimate point of contention), a very well known effect.  If the cable has non-negligible impedance, you will be able to measure a non-negligible drop across the cable itself, not to mention any differences in the signal seen by the load.

 

There are also plenty of relatively cheap 16 gauge zip cords out there that should work just fine, much cheaper than whatever the boutiques are selling.  Just because 24 gauge cheapo wire is a problem for longer runs to speakers doesn't mean that something cheap isn't okay.

 

Note that for many headphones, the length of cable is less and/or the impedance of the headphones is much greater.  Furthermore, many people are already using (and liking) headphone amps with 10, 30, 100 ohms output impedance of their own, so the impedance of the cable is going to be less than that (and effectively adds to the amount already from the amp output impedance).  Also consider that headphone drivers have less mass than speaker woofers.

 

Anyway, there are other articles on this that are better.

 

This, for example... also see the links on damping factor:

http://www.roger-russell.com/wire/wire.htm

 

I think damping factor is overrated by some, underrated by others.  At times, it can make a significant difference (not necessarily for the worse).  Others, not so much.

post #1586 of 3037

So basically to be safe, you should use the lowest gauge cable you can find. We know that 10 AWG cable is readily available to buy and it's dirt cheap. But then please explain this :

 

http://www.nordost.com/specification/33/odin-supreme-reference-speaker-cable

 

It says 20 x 20 AWG. I have no idea what that means. But here is my question. If this cable is 20 AWG then 10 AWG is going to offer far less resistance, correct? And this cable presumably costs thousands and thousands of dollars. So a $5 10 AWG cable offers lower resistance than this Nordost cable as linked? Correct me if I'm wrong.

post #1587 of 3037
Quote:
Originally Posted by Yahzi View Post

So basically to be safe, you should use the lowest gauge cable you can find. We know that 10 AWG cable is readily available to buy and it's dirt cheap. But then please explain this :

 

http://www.nordost.com/specification/33/odin-supreme-reference-speaker-cable

 

It says 20 x 20 AWG. I have no idea what that means. But here is my question. If this cable is 20 AWG then 10 AWG is going to offer far less resistance, correct? And this cable presumably costs thousands and thousands of dollars. So a $5 10 AWG cable offers lower resistance than this Nordost cable as linked? Correct me if I'm wrong.

 

24x20awg - those nordost cables bundle wires together, it is 24, 20 awg wires - biwired, so 6 per connector (each pole is 12x20) - so it is should be pretty low resistance overall. There might be other issues though (inductance/capacitance related).

post #1588 of 3037
Quote:
Originally Posted by Yahzi View Post

Any glaring issues in this article?

You mean besides making a mountain out of a molehill?
post #1589 of 3037
Quote:
Originally Posted by bigshot View Post


You mean besides making a mountain out of a molehill?

 

You obviously have no appreciation at all for the sheer amount of work it takes to make a mountain out of a molehill. Try it sometime. biggrin.gif

 

se

post #1590 of 3037
Quote:
Originally Posted by Steve Eddy View Post

 

You obviously have no appreciation at all for the sheer amount of work it takes to make a mountain out of a molehill. Try it sometime. biggrin.gif

 

se

 

Are we allowed to use more than one molehill, or is that cheating?

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