John Curl's Blowtorch preamplifier part IV

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#524
Markw4 said:
Pavel presented foobar ABX evidence, 9 out of 10 right after after some practice. He also said that ABX is much harder than he thought compared to simply listening to a real difference.

How do you feel about ABX being much more difficult than just listening to an real difference, just like the audiophiles have said all along?
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That is borderline underhand. Pavel has always been clear that and ABX result is the only thing he would consider as showing that a difference actually exists. And he holds himself to those standards.
 
#525
billshurv said:
...Pavel has always been clear that and ABX result is the only thing he would consider as showing that a difference actually exists...
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Come on, Bill. You don't recall that Pavel knows just like I know (and you at least once knew) that foobar ABX can be cheated. It is proof of nothing.

Not to mention that one 9/10 score proves nothing, even if foobar ABX was cheat-proof.
 
#527
Bonsai said:
The ear is surprisingly insensitive to GD - see Tomlinson Holman papers for example where this subject was touched on.
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Jumping a little too fast to conclusions ?
I dont care of the papers of one or another, I trust my ears, taking great care of Group delay in speakers since decades and I can assure-you it makes a difference.
One thing you can verify by yourself, comparing a digital equaliser with an analog equivalent. Reason why so many sound engineers continue to use big analog mixing desks for music.
 
#529
Hans Polak said:
This time we are in full disagreement.
A GD or time delay of 2msec at 8Kz means a pretty meaningless phase shift of 5760 degrees.
The same GD of 2msec means 1440 degrees at 2Khz.
So when the meaning of time delay in this case must be clear to everybody, what's the added value of knowing the phase shift.

Hans
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Hans,

1440 degrees is 4 times around the clock or a 16th order filter, 5760 16 times or a
64th order. For me, this direct relationship makes it easier to understand to begin with. But the real problem is that talking in terms of group delay means that the implication of a 2 ms group delay is different for each frequency.

If one thing can be two things and everything in between, that is for sure confusing

You measure phase shift by unwrapping the FFT, it is a more direct measurement than GD, which is derived from the phase shift measured thusly.

When I see a discussion where GD is used, I always have to recalculate it in terms of phase shift in order to make sense. Other brains are wired differently, but this being said, for the time being I prefer my own 🙂
 
#532
Markw4 said:
Pavel presented foobar ABX evidence, 9 out of 10 right after after some practice. He also said that ABX is much harder than he thought compared to simply listening to a real difference.

How do you feel about ABX being much more difficult than just listening to an real difference, just like the audiophiles have said all along?


I know you can't believe you could be wrong. It happens to people sometimes.

[/unquote]


Who said it was going to be easy? Nobody did.

The smaller the difference, the harder it gets.

But.....if you hear a difference in normal listening, you can train yourself to also hear it under ABX conditions. If not, you have been fooling yourself.

As long as you are prepared to fool yourself and keep it to yourself, you have my fool sympathy. Once you start fooling others, I am prepared to continue to play my self assigned role as public prosecutor. The gullible have to be protected against charlatans.
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#535
mountainman bob said:
This article seems informative, it’s hard to sort the unbiased information this one seems factual?
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Bob,
Since nobody else tried to answer your question, I will take the first stab at it: Many dacs over a choice of filter types that one is free to try and compare. (HQ Player software has many more filters to try, especially if the computer it runs on is powerful enough.)

Regarding dac filters:
Some people can't hear any of them, for those people it doesn't matter.

Other people can hear the filters and tend to find that which one sounds subjectively best depends on what else is still wrong with their dac and or maybe other parts of their system.

When a dac is cleaned up enough such that pretty much everything that can be fixed has been fixed, then usually the default filter sounds best overall. Most often that is a linear phase filter.

Not to say linear phase is perfect in all respects, IMHO it isn't. However, all the other filter choices have their own SQ issues which tend to make them subjectively worse sounding.

My personal experiences and observations only. YMMV.
 
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#536
Markw4 said:
When a dac is cleaned up enough such that pretty much everything that can be fixed has been fixed, then usually the default filter sounds best overall. Most often that is a linear phase filter.

My personal experiences and observations only. YMMV.
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So your DAC design criteria is "clean the DAC until the default filter sounds good".

And some were wondering what will be the next BS :rofl:. But because you added the YMMV you are excused this time.
 
#538
Mark,
I was more wondering if those articles I linked are sufficiently true to use for educational reference? I’m finding it hard to differentiate if what comes across as fact actually is......in other words sorting bs from fact when trying to educate myself. Pretty sure I’m not the only one wishing to learn but finding clear reference material difficult.

Thx

Edit.....this ‘chirp’ I referenced earlier also has me quite curious as it’s the first mention of it I’ve seen since actually hearing it during testing. (See 11.2 details)

Is Linear Phase
Really Ideal for Audio? | Introduction to Digital Filters
 
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#540
scottjoplin said:
Are you sure, how low does the HD have to be for the IMD to no longer be an issue?
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Typical measured levels above 22Khz are -60dbv. I had not checked a DAC lately... only out of CD/DVD players awhile back. But, I recently measured a new streaming DAC. Just put out on the market and the wide band noise/HF level above 22KHz was -60dbv average. Designer said it used the filter in the DAC chip and no other. But, that does not drive a speaker - it goes to line level/preamp source selector for 20db gain maybe. And, another 30db gain in power amp. So, level is much higher than DAC to PA and to SPKR/Tweeter.

Therefore, needs to be, IMHO, HF below .01% thd out of DAC.


THx-RNMarsh
 
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