The sound quality of DSD?

[Pluto]

I consider DSD a pox on our audio world.

Certainly an unwelcome distraction.

 

[Frank Dernie]

mansr presents his point of view as the true one and calling others to be a misconception. You can find many discussions on topic PCM vs. DSD and most of them are biased. So is also with the big font on "Misconceptions". One has simply try to look at the same thing from more points of view and the misconceptions disappear.

mansr wrote:
"If the negative-going pulses are disregarded, there is indeed a resemblance to a PDM signal. This interpretation is, however, not helpful. Any similarity to PDM is a coincidence, not a design intent, and viewing it as such does not aid analysis or understanding of 1-bit audio signals."
...
"As it happens, actual PDM is in fact analogue; it just has nothing to do with DSD. "
...
"The commonly used method of producing a 1-bit noise-shaped encoding of a signal is known as sigma-delta (or delta-sigma) modulation, sometimes abbreviated SDM"

from Wikipedia:

https://en.wikipedia.org/wiki/Pulse-density_modulation
"In a PDM signal, specific amplitude values are not encoded into codewords of pulses of different weight as they would be in pulse-code modulation (PCM); rather, the relative density of the pulses corresponds to the analog signal's amplitude. The output of a 1-bit DAC is the same as the PDM encoding of the signal. "

https://en.wikipedia.org/wiki/Pulse-density_modulation
"PDM is the encoding used in Sony's Super Audio CD (SACD) format, under the name Direct Stream Digital. "

https://en.wikipedia.org/wiki/Direct_Stream_Digital
"DSD uses pulse-density modulation encoding - a technology to store audio signals on digital storage media which are used for the SACD. The signal is stored as delta-sigma modulated digital audio, a sequence of single-bit values at a sampling rate of 2.8224 MHz "

So it is about different points of view and I would rather the wikipedia one consider a "standard" view. But I have nothing against an other angle of view if it is used to show something interesting.

If my experience is anything to go by Wilipedia is not a reliable source of facts. In my own business fans put in their opinions and obsessions as fact, when it is not and they have a very scant knowledge (rather than enthusiasm). They do not want to hear the facts if they clash with their existing opinion either.
There are actual technically thorough sources of data on digital audio so using Wikipedia is not necessarily going to give worthwhile information.
It is so inaccurate on technical stuff i know about I treat anything on there with great caution.

 

[BDWoody]

mansr presents his point of view as the true one and calling others to be a misconception.

Because he doesn't talk out of his ass.

 

[restorer-john]

If my experience is anything to go by Wilipedia is not a reliable source of facts. In my own business fans put in their opinions and obsessions as fact, when it is not and they have a very scant knowledge (rather than enthusiasm). They do not want to hear the facts if they clash with their existing opinion either.
There are actual technically thorough sources of data on digital audio so using Wikipedia is not necessarily going to give worthwhile information.
It is so inaccurate on technical stuff i know about I treat anything on there with great caution.

Quoting anything on Wikipedia as a source will get you thrown out (almost ) of university.

 

[Pluto]

Wilipedia is not a reliable source of facts

That just about sums it up!

 

[bogi]

You could easily find from other sources that DSD signal is a special case of PDM signal. The DSD signal is generated in delta sigma modulator, be it hardware or software solution. Delta sigma modulator outputs nothing other as PDM or PWM signal. I could cite other sources than Wikipedia but your reaction would be the same. You can find it self, but biased persons will not do it.

And this mansr's statement is really exotic:
"As it happens, actual PDM is in fact analogue; it just has nothing to do with DSD. "
Since DSD is 1bit 2 level PDM, mansr is saying that DSD is analog...
Delta sigma modulator implementation can be analog or digital. So the input can be analog or digital, depending on the implementation. And the same you can say about the output. You are using the output according to the goal you want to reach. That's the reason why delta sigma modulator can be used in both A/D and D/A converters.

 

[bennetng]

What I see in Wikipedia:

So I used mansr's SoX to make some sine wave DSD files, and converted to wav again, without resampling (2.8224MHz) and filtering.

A sine using a strong noise shaping modulator (sdm-8)

A sine using a weak noise shaping modulator (clans-4)

PCM with dithering only:

Actually, the PCM one looks more similar to Wikipedia's illustration, with a lot of consecutive max/min values. Quite funny.

The files look like this in frequency domain:

 

[Kal Rubinson]

The bones in the middle ear serve mainly as a piston arrangement between two cylinders of unequal area to provide hydraulic pressure amplitude gain.

Another issue, perhaps not directly relevant in this present thread discussion, is that the transfer function provided by the middle ear bones, as well as that provided by the external ear canal, is not flat across the audible range. There are resonances at frequencies in the 3-4kHz range that aid in language comprehension as they emphasis the range of human voice consonants. They also, of course, affect all sounds including music.

 

[JW001]

What PaulD said. Plus it usually isn't one bit DSD inside the chip. It can be, but usually isn't. It creates a format that is inconvenient to record with, edit and distribute. It is an additional format providing no benefits except for the audio phoo that goes with it. The PCM format in and out is what is most useful, and DSD has no purpose being pulled outside as another format.

My approach to this is practical. I agree that in an ideal world there would not be DSD recordings. But, the format exists, and there are many multi-channel SACDs out there. I own less than a hundred, some of them sound great, not because of the superiority of DSD over PCM, but because they are multi-channel and maybe just well recorded. I enjoy listening to them through my home theater setup.

 

[JustAnandaDourEyedDude]

What an excellent post.

The 'casual' knowledge on this forum is pretty amazing.

Cheers.

Thanks! The parts about hearing and the biomechanics of the ear came from re-reading and interpreting Monty Montgomery's article on why Hi-Res music makes no sense, and the Wikipedia articles on Hearing, Middle Ear, Inner Ear, Organ of Corti, etc. Education and long work experience as a mechanical engineer have given me quite a bit of background and analysis capability in mechanics of fluids and solids, both the physics and the math of it.

https://web.archive.org/web/20200426202431/https://people.xiph.org/~xiphmont/demo/neil-young.html
https://en.wikipedia.org/wiki/Hearing
https://en.wikipedia.org/wiki/Middle_ear
https://en.wikipedia.org/wiki/Inner_ear
https://en.wikipedia.org/wiki/Organ_of_Corti
https://en.wikipedia.org/wiki/Resonance

 

[JustAnandaDourEyedDude]

Another issue, perhaps not directly relevant in this present thread discussion, is that the transfer function provided by the middle ear bones, as well as that provided by the external ear canal, is not flat across the audible range. There are resonances at frequencies in the 3-4kHz range that aid in language comprehension as they emphasis the range of human voice consonants. They also, of course, affect all sounds including music.

I had come across mentions of the boost and resonances with regard to the ear canal, in connection with explanations of headphone frequency response curves. However, I was unaware that the middle ear bones response is not flat wrt frequency. Thanks for describing the transfer functions and their relation to language comprehension. It is another wrinkle in the amazing complexity of how hearing functions.

 

[Kal Rubinson]

I had come across mentions of the boost and resonances with regard to the ear canal, in connection with explanations of headphone frequency response curves. However, I was unaware that the middle ear bones response is not flat wrt frequency. Thanks for describing the transfer functions and their relation to language comprehension. It is another wrinkle in the amazing complexity of how hearing functions.

Loudspeaker sources are affected by both external anatomy (HRTF) and middle ear mechanics. Note that the middle-ear transfer function dominates for headphones.

From Oo, Nay & Gan, Woon-Seng & Hawksford, Malcolm. (2011). Perceptually-Motivated Objective Grading of Nonlinear Processing in Virtual-Bass Systems. AES: Journal of the Audio Engineering Society. 59. 804-824.

 

[danadam]

And this mansr's statement is really exotic:
"As it happens, actual PDM is in fact analogue; it just has nothing to do with DSD. "
Since DSD is 1bit 2 level PDM, mansr is saying that DSD is analog...

So you took "As it happens, actual PDM is in fact analogue" then ignored/dismissed "it just has nothing to do with DSD", replaced it with "Since DSD is 1bit 2 level PDM", which is exactly the opposite of what he said, and based on that concluded that "mansr is saying that DSD is analog". Seriously?

 

[JustAnandaDourEyedDude]

Loudspeaker sources are affected by both external anatomy (HRTF) and middle ear mechanics. Note that the middle-ear transfer function dominates for headphones.
View attachment 88418
From Oo, Nay & Gan, Woon-Seng & Hawksford, Malcolm. (2011). Perceptually-Motivated Objective Grading of Nonlinear Processing in Virtual-Bass Systems. AES: Journal of the Audio Engineering Society. 59. 804-824.

That clarifies the relationship between the transforms, thanks. The headphone curve involves mainly the middle ear, whereas the loudspeaker curves involve both the HRTF (with its pinna gain, diffraction around the head, etc.) and the middle ear transfer function. I had never quite put the two together, but that plot makes it clear.

 

[Atanasi]

I tried playing back DSD through DoP. If the DoP stream is being resampled to 44.1, the sound becomes noise with a faint echo of the original sound. Is this echo an intentional property of DoP, or is it accidental?

 

[Kal Rubinson]

Why is the DoP stream being resampled to 44.1?

 

[Atanasi]

Why is the DoP stream being resampled to 44.1?

That happens when exclusive mode is not used.

 

[krabapple]

That's too bad

No, only too late.

 

[krabapple]

Hair cells and the neurons attached to them don't care about the derivative of air pressure unless its steep enough to blow out your ear drum or dislocate the little bones(malleus incus and stapes) which which probably are part of the high freqency upper limitation in the ear. There are also muscles attached to those bones which if there are loud displacements will very quickly tension themselves to try to preserve your hearing at that greatful dead concert. Look up otoacoustic emissions to read more about that.

The only "research" I have seen that claims perception of ultrasonics is the article from Japan which smelled very funny to me and no one seems to be able to replicate. (EDIT: Oohashi mentioned above and the sponsorship was one of the things that smelled funny to me. Also I don't think it was his regular field of research. It certainly did not influence me. )

One of numerous non scientific experiments I have done with my system is to turn off the tweeter channel which normally runs from 5K up. You hardly notice it. I have turned it off while guests were listening and nobody ever caught me. All the victims were serious audio nuts.

Oohashi was a crank who fancies himself a polymath visionary. His doctoral degree was in Agriculture. If you look up his scholarly output, it's rife with nonsense in several fields. This article is laudatory, but its easy to read between the lines:

https://myanimelist.net/featured/743/The_Music_of_Akira

 

[Kal Rubinson]

That happens when exclusive mode is not used.

Oh. I rarely ever use DoP (except when testing something), so I have not experienced it.