• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Can you tell 8-bit file from 16-bit file in a DBT? Listening test, RLJ

OP
pma

pma

Major Contributor
Joined
Feb 23, 2019
Messages
3,313
Likes
6,908
Location
Prague
44.1/8-bit byproduct with the 44.1/16-bit original?

Such test with 44.1/8 file is pointless, with tons of audible noise. There is not enough space for noise shaping. Of course I did that.

My point is different - to show that even 8 bit resolution done with psychoacoustically proper dither does not degrade the perceived sound in the way that one would expect. Regardless the single number SINAD of less than 40 dB. I want to show that the single number 20kHz BW SINAD is pointless, from the perception point, without knowledge of signal spectrum.

signal_44_8b_dithered_-2dB.png

SINAD = 37.3 dB

signal_44_16b_to_96-8_shapeddithered.png

SINAD = 35.1 dB


Regarding your opinion of:
the variable of bit-depth
The bit depth is not variable here, the bit depth is 8 bit. Please read the post #36 again. ENOB is variable but only in case that we accept lower measuring bandwidth than 20kHz. For 20kHz BW, ENOB is low again.
 
OP
pma

pma

Major Contributor
Joined
Feb 23, 2019
Messages
3,313
Likes
6,908
Location
Prague
The concept of dither is so obscure

It is definitely not obscure. As in many fields of human activities, one must know what he is doing and must have some education in the field of work or field of interest. Not everything can be explained to everyone and understood by everyone.
 

tmtomh

Major Contributor
Joined
Aug 14, 2018
Messages
1,589
Likes
4,873
Such test with 44.1/8 file is pointless, with tons of audible noise. There is not enough space for noise shaping. Of course I did that.

My point is different - to show that even 8 bit resolution done with psychoacoustically proper dither does not degrade the perceived sound in the way that one would expect. Regardless the single number SINAD of less than 40 dB. I want to show that the single number 20kHz BW SINAD is pointless, from the perception point, without knowledge of signal spectrum.

View attachment 224052
SINAD = 37.3 dB

View attachment 224053
SINAD = 35.1 dB


Regarding your opinion of:

The bit depth is not variable here, the bit depth is 8 bit. Please read the post #36 again. ENOB is variable but only in case that we accept lower measuring bandwidth than 20kHz. For 20kHz BW, ENOB is low again.

Oh. my. goodness. Testing with a 44.1k/8-bit file isn't "pointless" - rather, it just doesn't produce the outcome you want. That's an important difference.

"Even 8 bit resolution done with psychoacoustically proper dither does not degrade the perceived sound in the way that one would expect" - IF ONE FIRST UPSAMPLES THE SIGNAL IN ORDER TO GET A LOT OF THE NOISE OUT OF THE AUDIBLE SPECTRUM.

That qualifier is the point - and while it is refreshingly honest to see you say that this is yet another attempt at your dumb crusade against @amirm 's use of SINAD, it is also depressing and frustrating, as it creates confusion rather than enlightenment, per @danadam 's recent comment.

You pull this kind of BS over and over and over again here on these forums. It's so tiresome.
 
OP
pma

pma

Major Contributor
Joined
Feb 23, 2019
Messages
3,313
Likes
6,908
Location
Prague
Oh. my. goodness. Testing with a 44.1k/8-bit file isn't "pointless"

I do not want to argue and to debate. If you insist, here is the best 44.1kHz/8bit file I can do (regarding noise audibility), with C3 noise shaping.
It is a true 44.1kHz/8bit file.


And this is the dither used FYI. Contrary to the 96/8 file, there is no space to make effective noise shaping to get good result below 1kHz. However, audibly it is much less noisy than the usual TPD flat dither.

signal_44_8b_C3dithered_-2dB.png


DeltaWave results between original 44.1/16 and 44.1/8 music test sample files

1660478558973.png


1660478598250.png
 
Last edited:

bennetng

Major Contributor
Joined
Nov 15, 2017
Messages
1,563
Likes
1,582
Forgive my hijacking, but this thread seems highly relevant to an experimental audio format I made earlier, here is a snippet of the readme file:
UA-law is an experimental audio format inspired by the u-law and A-law companding algorithms, incorporated with noise shaping and optimized adaptive quantization to improve transparency, without using methods commonly found on typical perceptual codecs like MDCT, filterbank, ADPCM and so on. UA-law accepts .wav and .flac files with 16 and 24 bits and unlimited sample rates, mono to multichannel formats up to 4GB uncompressed PCM file size. UA-law uses 8 bits to encode 16-bit files and 12 bits to encode 24-bit files.
The executable and source code can be downloaded here:

So everyone can use their preferred audio files to perform listening tests and I can't cherry pick samples. I would like to see people posting their non-test signal audio samples and ABX results instead of FFT plots and such. In my own tests I can say the 8-bit version of UA-law may not be 100% transparent with some specific materials, but I can say my method has a much higher chance to achieve transparency than the traditional approach used by pma's version of Audition.
 

danadam

Addicted to Fun and Learning
Joined
Jan 20, 2017
Messages
685
Likes
998
My point is different - to show that even 8 bit resolution done with psychoacoustically proper dither does not degrade the perceived sound
We already know, that even 1 bit is ok if you have enough bandwidth.

The bit depth is not variable here, the bit depth is 8 bit.
This is not what "to isolate the variable of bit-depth" means. When you claim to compare 8 and 16 bits, then bit-depth should be the only variable that changes. And you changed two variables, bit-depth and sampling rate.

But also, no, the bit-depth is not 8 bit throughout. When you convert 96/8 to 44, then first in this process is a low-pass filter. It creates new samples and those new samples need more than 8-bits, if they are to reproduce 0-22k spectrum of the 96/8 file. Sorry, something has to give. If you remove the noise from the 22k-44k band, then you either have to increase the bit-depth or accept that the noise floor in the 0-22k band will increase.

The only thing that can be said here, is that 44/16 reproduces the 0-22k spectrum of the 96/8 file, but to do so it needs more than 8 bits.

Frankly I don't understand what's the point of this smokescreen with 8 and 16 bit, if all you wanted to show is that 40 dB sinad can sound ok. If you named this thread "Can you tell 40 dB sinad from 90 dB", then no one would bat an eye. Well, at least I wouldn't :).
 

Madlop26

Active Member
Forum Donor
Joined
May 2, 2021
Messages
140
Likes
232
Well , for what is worth, very easy test with my HD800s, it seems I can tell clearly the difference from 40 dB sinad from 90 dB, thank you for the demonstration of the importance of Sinad, lol
 
Top Bottom