16 bit vs 24 bit, any samples that work? Options

[AndyH-ha]

There are real differences between 16 bit and 24 bit files, just as there are real differences between uncompressed and mp3. As with the differences between wav and mp3, 16 bit vs 24 bit is often difficult to identify by listening.

Test signals are one thing, but has anyone found any 24 bit music recording that can be successfully identified via ABX testing against a properly resample to 16 bit version of same?

[2Bdecided]

Found it...

http://www.gearslutz.com/board/so-much-gea...ot-audible.html

...interesting thread. Some amazing miscomprehension in there, but still interesting.

I'm not saying you can't hear it. My own algorithm (lossyWAV) says you can. (But I can't!). It's just that 90%+ of people who come to HA claiming to hear a difference between 16-bits and 24-bits, or 44.1kHz and 96kHz, are really hearing problems with their equipment.

Potential equipment "problems" aside, would you be willing to try another ABX or two?

Cheers,
David.

This post has been edited by 2Bdecided: Jan 23 2009, 16:51

[krabapple]

Found it...

http://www.gearslutz.com/board/so-much-gea...ot-audible.html

...interesting thread. Some amazing miscomprehension in there, but still interesting.

I'm not saying you can't hear it. My own algorithm (lossyWAV) says you can. (But I can't!). It's just that 90%+ of people who come to HA claiming to hear a difference between 16-bits and 24-bits, or 44.1kHz and 96kHz, are really hearing problems with their equipment.

Potential equipment "problems" aside, would you be willing to try another ABX or two?

Cheers,
David.

Let me get this straight... comparisons were 24bit vs dithered-to-16, and another was 24-bit .wav , converted to 16 vs 320 mp3 made directly from the 24 bit .wav ...and at least TWO people in this tiny sample of subjects managed perfect or near-perfect ABX scores on both -- with the mp3 trial reported being HARDER to ABX than the wordlength comparison??? (Except for the THIRD guy who claims he aced the 320 lossy vs lossless ABX, while failing to score significantly on the wordlength ABX). And another guy got 10/10 on just the wordlength ABX?

But Martin K can't successfully ABX two files made using Chris Johnson's superspecial dither?





I'm not implying nefarious intent on Martin K.s part, but to me these data suggest an obvious control: someone here needs to replicate the sample pairs (take the original 24-bit .wav and convert to 16 bit with TPDF dither; take the 24-bit file and convert it to 320 mp3), and see how those guys 'over there' do at ABX'ing them.

This post has been edited by krabapple: Jan 24 2009, 01:41

[Martin Kantola]

But Martin K can't successfully ABX two files made using Chris Johnson's superspecial dither?

My result for the "avd" dither was 8/10, as posted in the thread. And yes, I really want to see more people trying this too! Regardless of outcome. But so far many many posts, but very few ABX results.

You are welcome scrutinize my conversions, I'd be happy to correct any mistakes I might have made, but these are very basic operations on a DAW, honestly think I can handle them.

Martin

[MLXXX]

My result for the "avd" dither was 8/10, as posted in the thread. And yes, I really want to see more people trying this too! Regardless of outcome. But so far many many posts, but very few ABX results.

You are welcome scrutinize my conversions, I'd be happy to correct any mistakes I might have made, but these are very basic operations on a DAW, honestly think I can handle them.

Martin

Martin, congrats for posting the test files, and for the persistence in doing the ABX trials; particularly the 100 trials of the version with 'a little high pass noise'!

I have not tried to ABX the 24bit original against the 16 bit dithered versions (with or without extra noise) because in the past I have found that 24 bit music dithered to 16 bits (with a noise shaped dither) sounds the same to me as the original 24 bits, at normal recording and playback levels.

The effort required for ABX testing can be considerable. In my own case, my ears/brain are most responsive the first time I am presented an AB comparison. If the passage is repeated, my hearing discrimination rapidly diminishes. So to commit myself to an ABX comparison of very similar files I have to set aside a fair stretch of time, to allow my hearing to regain its sensitivity to fine differences.

Before attempting a serious ABX I would like to be assured that the 16 bit dithered version has been derived using methodolgy to the satisfaction of HA Forum technical gurus, e.g. a dither conversion they have run themselves, and preferably that at least one person has successfully ABXd such an 'approved' dithered version. Perhaps that is laziness on my part!

No disrespect intended to yourself, but I can foresee reluctance of the HA community to accept any ABX test result unless all possible perceived doubt has been removed as to the reliability of the methodolgy for performing the dither.

[Out of interest, I did ABX tests of just 4 trials of the truncated version, and 4 trials of the 320kbps mp3 version, relative to the respective 24 bit originals. I found the truncated version relatively easy to distinguish. But the 320kpbs version needed a lot of concentration and 'refresher breaks'. The 4 correct answers I obtained in both cases merely corresponded to a 6.2% likelihood of not guessing. But all I was seeking was broad assurance I could distinguish the files. They were not what I'd call 'serious' ABX tests.]

Cheers

This post has been edited by MLXXX: Jan 28 2009, 12:56

[krabapple]

The effort required for ABX testing can be considerable. In my own case, my ears/brain are most responsive the first time I am presented an AB comparison. If the passage is repeated, my hearing discrimination rapidly diminishes. So to commit myself to an ABX comparison of very similar files I have to set aside a fair stretch of time, to allow my hearing to regain its sensitivity to fine differences.

Is it the repetition of A/B comparison itself, or the repetition of the same music in a series of A/B comparisons, that you find fatigueing?

If it's the latter, I wonder if it might make discrimination easier, to prepare a batch of 16 different samples -- and use a different one for each of 16 trials. Then at least each A/B is 'fresh' to the ears.

For ease of preparation, the samples could be 16 different parts of the same track. If that's not a concern, they could be from different tracks (all prepared and vetted to HA standards as you have described)

This post has been edited by krabapple: Jan 27 2009, 18:57