Topic: The difference between 16/44 and 24/96 can not be heard

[Petrus]

From AES Journal 2007 September, Volume 55 Number 9:

"Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback

E. Brad Meyer and David R. Moran 775

Conventional wisdom asserts that the wider bandwidth and dynamic range of SACD and DVD-A make them of audibly higher quality than the CD format. A carefully controlled double-blind test with many experienced listeners showed no ability to hear any differences between formats. High-resolution audio discs were still judged to be of superior quality because sound engineers have more freedom to make them that way. There is no evidence that perceived quality has anything to do with additional resolution or bandwidth."

Test were done with a high grade stereo system and over one hundred test persons. Nobody could hear the difference between SACD and CD standard audio.

[it-goes-to-eleven]

We've discussed that before on TS.  I think your subject for the post is too broad and takes way too much for granted.  The publication you cite only considered the narrow category of commercially mastered releases and not, for example, raw live audio.

[Petrus]

It is quite easy to make a test file and try this at home:

- get a true 24/96 recording (I bough one from Linn web shop, FLAC "Studio master" of Prokofiev's 1. symphony)
- convert to AIFF or WAV for processing, keep resolution at 24/96
- Join the traks into one file (4 tracks in this case, total of 14:20)
- cut the file into 30 second clips (28 clips in this case)
- copy clips, convert to 16/44.1 and back to 24/96
- throw dice to deside which resolution clips are used
- join the clips back to form the original perfirmance, some random clips those that were downrezzed 16/44.1, others 24/96 as decided by dice
- listen to the file with a good player capable of true 24/96 performance (I use SD722)
- make you own conclusions.

You can use this with friends by either asking at every 15+n30 seconds it the audio is hi or low resolution, or every n30 seconds if there was a change compared to previous clip.

This method bypasses the need for comparator, level setting etc. If you are really interested in finding out if you can hear the difference this is the way to test it. 

[Petrus]

haha... how lame...

For all I know Sound Devices claim this on their spec sheet:
-------
A/D, D/A Converters:
24 bit, 192 kHz sample rate maximum

D/A Dynamic Range:
112 dB, A-weighted bandwidth
108 dB, 20 Hz–22 kHz bandwidth
-------

The power of SD722 is its high S/N ratio, and that it is mechanically quiet. With PC or Mac you get fan/HDD noises, only the best separate sound cards have decent S/N ratios approaching even 16bit dynamic range.

Then again, if your best system can not differentiate between 16/44.1 and 24/96, then does it matter if you could???

[Frank in JC]

"From AES Journal...
A carefully controlled double-blind test with many experienced listeners showed no ability to hear any differences..."

I think the AES would even have a difficult time establishing a difference between shit and shinola

[StuStu]

It is quite easy to make a test file and try this at home:

- get a true 24/96 recording (I bough one from Linn web shop, FLAC "Studio master" of Prokofiev's 1. symphony)
- convert to AIFF or WAV for processing, keep resolution at 24/96
- Join the traks into one file (4 tracks in this case, total of 14:20)
- cut the file into 30 second clips (28 clips in this case)
- copy clips, convert to 16/44.1 and back to 24/96
- throw dice to deside which resolution clips are used
- join the clips back to form the original perfirmance, some random clips those that were downrezzed 16/44.1, others 24/96 as decided by dice
- listen to the file with a good player capable of true 24/96 performance (I use SD722)
- make you own conclusions.

"- copy clips, convert to 16/44.1 and back to 24/96"
Hmmm...am I missing something here? I mean, if i convert a file file from 24/96 to 16/44.1, and then convert back to 24/96, I'm not listening to a true clone of the original 24/96 recording. I'm listening to a redbook quality recording in 24/96. Right?   

[Jammin72]

It is quite easy to make a test file and try this at home:

- get a true 24/96 recording (I bough one from Linn web shop, FLAC "Studio master" of Prokofiev's 1. symphony)
- convert to AIFF or WAV for processing, keep resolution at 24/96
- Join the traks into one file (4 tracks in this case, total of 14:20)
- cut the file into 30 second clips (28 clips in this case)
- copy clips, convert to 16/44.1 and back to 24/96
- throw dice to deside which resolution clips are used
- join the clips back to form the original perfirmance, some random clips those that were downrezzed 16/44.1, others 24/96 as decided by dice
- listen to the file with a good player capable of true 24/96 performance (I use SD722)
- make you own conclusions.

"- copy clips, convert to 16/44.1 and back to 24/96"
Hmmm...am I missing something here? I mean, if i convert a file file from 24/96 to 16/44.1, and then convert back to 24/96, I'm not listening to a true clone of the original 24/96 recording. I'm listening to a redbook quality recording in 24/96. Right?   

I think he's suggesting that you have to convert the ones you dithered/re sampled back to 24/96 so that they can be rejoined and played back seamlessly in the final product.  I would be surprised if all of that processing didn't make a difference in and of itself on the sound stage in those sections.

[Petrus]

Correct, by doing the 24/96 -> 16/44 > 24/96 route you can seamlesly join the clips back to an apparent 24/96 file but some clips are actually only 16/44 resolution. Easy to do, easy to test if you can hear the difference. I did this to a Linn "Studio Master" 24/96 file with Adobe audition and can not hear where the music was cut & downsampled.

Surprised you might be, maybe also disapointed...

Basically that conversion does not touch the 15 most important bits, and dithering only the last half bit depending on the settings, upconversion basically does nothing but adds the missing 8 zeros to the end and have absolutelly zero effect on the sound quality. This would be the case with 44.1 - 88.2 kHz conversions, recalculation needed for 96 - 44.1 -96 operations generate some artefacts, but apparently they can not be heard.

Like I said, nice exercise, does not cost anything if you have a true hi-rez file to manipulate (be carefull with the naming of files), needs no special test arrangements.

[StuStu]

Gotcha. Thanks for the clarification.

[Petrus]

I have to admit that the subject for this thread is not correct. The original comparason was between SACD and CD resolutions, and my experiments with Linn Studio Master files (marketed as 24/96) shows, and net information confirms this, that they are not even near true 24/96 PMC quality.

So, next I have to get my hands on a REAL 24/96 high quality classical music file...

If it would make any difference.

[Corporate hack]

out of curiosity, Petrus, is your name on here a reference to the wine?

[Petrus]

eh.., yes, we have both aged gracefully...

[Corporate hack]

eh.., yes, we have both aged gracefully...

I'll stop derailing this conversation, but you've got to see this:

http://www.thisislondon.co.uk/news/article-23436394-details/The+moment+a+diner+sent+back+an+%C2%A318%2C000+bottle+of+wine+-+for+being+%27fake%27/article.do

[dean]

I have to admit that the subject for this thread is not correct. The original comparason was between SACD and CD resolutions, and my experiments with Linn Studio Master files (marketed as 24/96) shows, and net information confirms this, that they are not even near true 24/96 PMC quality.

So, next I have to get my hands on a REAL 24/96 high quality classical music file...

If it would make any difference.

Talk to Moke about this.  He records classical in 24/96 almost exclusively...

[noahbickart]

1) We should all agree that headroom concerns alone dictate that it is preferable to record at 24 bit. That way you can run your levels more conservatively without any loss of dynamic range.

2) I think the playback gear is a very important factor which has largely been ignored in this thread (except by Freelunch). I've been playing Petrus's test game with some SKB 24bit onstage Schoeps pulls from the rchive, using an Apogee Mini-DAC and my AKG k701's. The difference is there, especially when you know what to listen for. I can not, for example, hear the difference with my speaker setup, which isn't bad.

-Noah