Comparison: PCM DXD DSD (Sound Liaison High Res Format Comparison)

[Frgirard]

As do most transducers. There will be very few speakers of headphones that produce anything above 40 kHz. Most amps won’t go much higher either, and some even will get unstable when feeding ultrasonic (design flaw obviously).

What is the link with the ultrasonic hear?
Read what is wrote and no what you want.

 

[richard12511]

This comparison of different music formats is not a comparison of different formats at all. This only compares different formats of one single recording that was not done well. This is not representative of all dsd recordings, or even a significant percentage of them. This review should have been titled ”how dsd is not a guarantee of better sound quality”. How about comparing a really good dsd recording to a really good redbook recording? Is there any scientific way to prove that dsd provides no sonic benefits over redbook? I doubt it. I am concerned that people will view this and think that there is no value to hi resolution recordings at all and recording technology will be stuck in the 1980’s for the next 50 years.

In my view DSD is clearly inferior to redbook. File size is much larger(many of my DSD files are 20-30 GB), and sound quality is exactly the same.

 

[voodooless]

What is the link with the ultrasonic hear?
Read what is wrote and no what you want.

To potentially hear it, it needs to be produced in the first place. Not so hard to understand, is it?

 

[Frgirard]

My

To potentially hear it, it needs to be produced in the first place. Not so hard to understand, is it?

The day you will hear the ultrasonic sound it's not come.
You don't understand what is your hearing.

 

[voodooless]

My

The day you will hear the ultrasonic sound it's not come.
You don't understand what is your hearing.

I think it's more about you not understanding what I'm writing... I'm not claiming to hear anything. What do you think I'm saying?

 

[sebackman]

I'm a little at a loss here.

There is normally no desired music content above 20k and if it was we can't hear it. The graphs clearly shows that there is no doubt "signal content" above 20k in the files analysed, which is most likely unwanted noise. There has also been some comments that this may harm the chain further down and even harm a tweeter.

But would not the brick wall output filter in the DAC filter out all of that?? Hence nothing, or a very limited amount, would ever reach the amplifier and/or the speakers? If that is correct, introducing a new steep DSP filter at 20k after the DAC filter would make very limited difference.

I'm not saying that it is ok with a lot of garbage above 20k in the files and maybe this introduces artefakts in the digital chain or the DAC, but we should not really be worried about amps, speakers or ears??

 

[Frgirard]

I'm all little at a loss here.

There is normally no desired music content above 20k and if it was we can't hear it. The graphs clearly shows that there is no doubt "signal content" above 20k in the files analysed, which is most likely unwanted noise. There has also been some comments that this may harm the chain further down and even harm a tweeter.

But would not the brick wall output filter in the DAC filter out all of that?? Hence nothing, or a very limited amount, would ever reach the amplifier and/or the speakers? If that is correct, introducing a new steep DSP filter at 20k after the DAC filter would make very limited difference.

I'm not saying that it is ok with a lot of garbage above 20k in the files and maybe this introduces artefakts in the digital chain or the DAC, but we should not really be worried about amps, speakers or ears??

 

[Frgirard]

When your listen a trumpet or a cymbal in the real-world are you silly?
No.

So what is the issue?

 

[Francis Vaughan]

But would not the brick wall output filter in the DAC filter out all of that??

The DAC filter is the reconstruction filter. It is set at the Nyquist frequency, so if the DAC is capable of 192kHz, the reconstruction filter will be placed so as to be as near full cut off at 96kHz as possible. It can be a lower frequency, but from a theoretical point of view that is the maximum. If the actual equipment applies more filtering after the DAC proper, that is a different matter.
OTOH, a DAC might resample the higher sample rate down to a lower rate. Whatever the final rate is, that determines where the reconstruction filter goes, or at least the highest frequency it can be placed.

There is very little to no evidence that any energy above 20kHz is of any value or perceivable. Given most tweeters will turn the energy into heat and emit little to no actual sound it is pretty clear it is a waste of time.

 

[sebackman]

Thank you for explaining. So in Amir's tests of DAC's where the frequency drops after 20k in the graphs, the DAC graph would show a lot of "garbage" way over 20k if they were fed 384k data (with noise over 20k) and capable of handling that sample rate?? I thought that there was a fixed low pass filter at about 20k and that some manufacturers provide for the choice of steep or slow roll off. But always from about 20k? Do I interpret your answer correct in that the f0 of that low pass filter is a function of the used sampling rate, meaning that measurable garbage/noise well above 20k can actually reach the analogue output of the DAC at meaningful levels? I will have to be a digital filter as it drops the level about 80db after 20k-ish

 

[Nango]

Thank you for this eye opener, @amirm

It is blatantly obvious that mastering of these so called hi-resolution tracks are not correct. I don't see this as the label's fault. We have mastering engineers for a reason. I'm 100% sure that all those tracks and versions are processed by one or more mastering engineer. It is them who should stand up, took the blame and correct their mistakes.

I wonder if there are any mastering engineers in this forum? I like to hear their comments on this.

Don't think graduated mastering or sound engineer are covering these productions. I think it is just one person who thinks with the right environment and one software or app he can do an album. They don't pay for engineers if there is s software available for all these works. Pure profesional intrusion and infringement.

 

[dualazmak]

Thank you for explaining. So in Amir's tests of DAC's where the frequency drops after 20k in the graphs, the DAC graph would show a lot of "garbage" way over 20k if they were fed 384k data (with noise over 20k) and capable of handling that sample rate?? I thought that there was a fixed low pass filter at about 20k and that some manufacturers provide for the choice of steep or slow roll off. But always from about 20k? Do I interpret your answer correct in that the f0 of that low pass filter is a function of the used sampling rate, meaning that measurable garbage/noise well above 20k can actually reach the analogue output of the DAC at meaningful levels? I will have to be a digital filter as it drops the level about 80db after 20k-ish

Hello sabackman,

I am actually analyzing and testing your points using my multichannel multi-driver multi-amplifier system with OKTO DAC8PRO and software digital crossover EKIO. If you would be interested, please visit my project thread especially post #362 and thereafter.

 

[sebackman]

@amirm
As a result of your video and the above discussion can you please do an experiment for us.

Please feed a high rez file (high sample rate >=192kHz), like in the video, that you know contain lots of above 20k noise (or whatever it is) into any decent quality high rez capable DAC and measure what comes out on the analogue side. Do we have high frequency garbage there also? Your splendid measuring equipment can most likely track any >20k signal residual on the analogue side, if any.

I would guess that the low pass filter in the DAC would take care of that and the output would be as in your graphs (dropping 80db after 20k-ish) regardless of sample rate input into the DAC and regardless of the digital garbage above 20kbut in the input file. But as said just a guess.

If there is no noise above 20k after the DAC filters we can all feel safe with regards to amps and tweeters, if not....

This is not a post to question the fact that some expensive high rez files seem contain unwanted garbage above 20k, but that is a separate question

 

[Frgirard]

@amirm
As a result of your video and the above discussion can you please do an experiment for us.

Please feed a high rez file (high sample rate >=192kHz), like in the video, that you know contain lots of above 20k noise (or whatever it is) into any decent quality high rez capable DAC and measure what comes out on the analogue side. Do we have high frequency garbage there also? Your splendid measuring equipment can most likely track any >20k signal residual on the analogue side, if any.

I would guess that the low pass filter in the DAC would take care of that and the output would be as in your graphs (dropping 80db after 20k-ish) regardless of sample rate input into the DAC and regardless of the digital garbage above 20kbut in the input file. But as said just a guess.

If there is no noise above 20k after the DAC filters we can all feel safe with regards to amps and tweeters, if not....

This is not a post to question the fact that some expensive high rez files seem contain unwanted garbage above 20k, but that is a separate question

Have you used audacity or other like audacity to see the level of the différentes frequencies?
What is after 10khz is not an issue.

 

[danadam]

the f0 of that low pass filter is a function of the used sampling rate, meaning that measurable garbage/noise well above 20k can actually reach the analogue output of the DAC at meaningful levels?

Yes. Here's a spectrogram of a file with a 20 - 48'000 Hz sweep:

And here's the output of a DAC (old motherboard, ALC889A) playing that file:

 

[dualazmak]

Hello sebackman,

This morning, using PC's Realtek-HD audio chip (not so HiFi), I could quickly check and confirm that DAC8PRO "nicely and correctly" outputs the HF noises into analog sides. Please visit my post #368 in my multichannel multi-driver multi-amplifier thread.

 

[sebackman]

That is scary indeed. I will try to see if my system do the same. If so I will copy your suggestion to add a 20kHz XO @48db/okt.

 

[amirm]

@amirm
As a result of your video and the above discussion can you please do an experiment for us.

Please feed a high rez file (high sample rate >=192kHz), like in the video, that you know contain lots of above 20k noise (or whatever it is) into any decent quality high rez capable DAC and measure what comes out on the analogue side. Do we have high frequency garbage there also? Your splendid measuring equipment can most likely track any >20k signal residual on the analogue side, if any.

I would guess that the low pass filter in the DAC would take care of that and the output would be as in your graphs (dropping 80db after 20k-ish) regardless of sample rate input into the DAC and regardless of the digital garbage above 20kbut in the input file. But as said just a guess.

If there is no noise above 20k after the DAC filters we can all feel safe with regards to amps and tweeters, if not....

This is not a post to question the fact that some expensive high rez files seem contain unwanted garbage above 20k, but that is a separate question

I have done this and garbage most definitely is output by the DAC. if it did not, it would not be a proper dac. Increasing sample rates needs to increase the bandwidth.

 

[sebackman]

I did a quick check on a bunch of files including some hi rez files I bought. None gave the same amount of garbage as the DSD files. Some the 24/96 files in wav format I have bought did not shown any garbage above 20k, or at least 80db down. Using wide band amps may cause a problem for some of us, using DSD files. My tweeters extend to 40k, don´t want ot hear that... Well I don´t hear it, but I don´t want it to affect what I can hear.

Is there any drawback with introducing a steep LP at +20K in XO/DSP, as dualzmak is suggesting? This would be before the DAC.

 

[dualazmak]

Hello sebackman and amirm,

As shared in my post #365 in my thread, I am very carefully and intensively testing/comparing High-Cut LR (Linkwitz–Riley) filters at 22.049 kHz (not at 20 kHz) with different cut-off slopes of -12 dB/Oct, -24 dB/Oct and -48 dB/Oct. We are on the way of our quasi-blinded ABCx comparative listening sessions;

Even though over 22.049 kHz is inaudible Fq range, we can hear very very subtle audible differences between these three slopes.

I once read that 22 - 50 kHz sound cannot be heard with simple sine-wave-tone tests, but when mixed with high quality music sound of 10 - 20 kHz, the 22 - 50 kHz sound may have unproved "audible preferable effects". Someone discussed this magic effect in terms of our "bone conduction", but I am rather doubtful since we usually cannot hear over 15 kHz through "bone conduction."

I assume that the "very very subtle audible differences" would be related to the "phase rotations" or "phase complications" in 20 - 50 kHz range, but I have no objective tool to measure them. (I have only one measurement microphone BEHRINGER ECM8000 which can hear up to 20 kHz.)

I would like to decide, therefore, the choice of the high-cut slope out of the three by our very careful quasi-blinded ABCx listening sessions still going on for the coming two weeks or three. When decided, I will get back to you in my thread.