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Topic: PCM, DSD - Trying to get my head round some basics (Read 42822 times) previous topic - next topic
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Re: PCM, DSD - Trying to get my head round some basics

Reply #125 –
Quote from: bennetng on
Before I am getting more replies, let me make a guess...

Since file conversion is a non-realtime process, so adjustment can always be made afterwards, and SoX made such a correction?
Seems so. izotope lately fixed the sample allignment also.
I wonder after all the posts about SoX at HA people still fiddle around with other half-baked resampler options!?
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Re: PCM, DSD - Trying to get my head round some basics

Reply #126 –
Quote from: Case on
Quote from: bennetng on
The point I don't understand is the SoX plugin can be easily downloaded and checked and by default (see the screenshot setting) it can already give a super beautiful sweep, why there is no delay?
Any resampler could compensate for the delay. It's just a matter of dropping the extra silent samples.
For plugins i guess the offset relates in big part to the host. Not sure the SoX plugin can work as proper as SoX standalone.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Re: PCM, DSD - Trying to get my head round some basics

Reply #127 –
Quote
Any resampler could compensate for the delay. It's just a matter of dropping the extra silent samples.

They are not necessarily silent, though - if the source doesn't start with silence, they are "pre-ringing" oscillations (albeit with small amplitude)

Re: PCM, DSD - Trying to get my head round some basics

Reply #128 –
Quote from: Wombat on
I wonder after all the posts about SoX at HA people still fiddle around with other half-baked resampler options!?
Because SoX is free and popular, it must be mediocre.

Re: PCM, DSD - Trying to get my head round some basics

Reply #129 –
Quote from: Case on
If you look at my short test you see that David's version has values varying all over the place too depending on the sample rate.
Nonsense:
Quote from: Case on
Sample rateITUOriginal
352.8 kHz-3.99 dB-1.98 dB
192 kHz-0.96 dB-3.74 dB
48 kHz-1.47 dB-1.98 dB
44.1 kHz-1.47 dB-2.07 dB
Quote from: Case on
The 192 kHz file gives entirely different results than the others.
True, but as you were so quick to point the finger at an implementation bug (44.1 vs 48), let's not rule this out as a possibility for 192.

Quote from: Case on
It's weird how you are in such a disagreement with the new scanner. I have files from all genres except rap and jazz and I'm pleased with the volume leveling.
It's not weird at all.  I'm not at all pleased with the leveling for metal.  I suspect it is because metal has more prevalent HF content causing 1770 to over-compensate because it doesn't implement an effective equal loudness filter.  If you're trying to model the human perception of loudness I would think one should use a proper model of human frequency response and I suspect 1770 is lacking in this regard, if not inferior to the original algorithm at the very least.  That Peter needs to add an ultrasonic bandaid in order to get the new algorithm to spit out accurate results only stands to confirm my suspicions.

Quote from: Case on
Edit: forgot to mention that you can still use the old ReplayGain scanner before libebur128 implementation by manually replacing the foo_rgscan.dll file. You can find the last version in foobar2000 v1.1.5
Thanks! YAY!!!!

Re: PCM, DSD - Trying to get my head round some basics

Reply #130 –
Quote from: judd on
They are not necessarily silent, though - if the source doesn't start with silence, they are "pre-ringing" oscillations (albeit with small amplitude)
Pffft.

What's the frequency of this pre-ringing again?!?

Please don't interpret this as my being critical of you, judd, rather I see pre-ringing as the new jitter; striking fear in the hearts of placebophiles.

Re: PCM, DSD - Trying to get my head round some basics

Reply #131 –
Quote from: greynol on
Pffft.
What's the frequency of this pre-ringing again?!?

why is that relevant ?
My point was about truncating non-zero samples.
It's probably not a big concern, but then neither is a sub-1ms delay.

Re: PCM, DSD - Trying to get my head round some basics

Reply #132 –
You posted while I was in the midst of an edit, as I suspected you would take it the wrong way and get defensive.
Quote from: greynol on
Please don't interpret this as my being critical of you, judd, rather I see pre-ringing as the new jitter; striking fear in the hearts of placebophiles.
My apologies for not having the foresight to initially include it prior to posting.

(EDIT: I decided to split the infinitive rather than put initially at the end.)

Re: PCM, DSD - Trying to get my head round some basics

Reply #133 –
Quote from: greynol on
You posted while I was in the midst of an edit, as I suspected you would take it the wrong way and get defensive.
Quote from: greynol on
Please don't interpret this as my being critical of you, judd, rather I see pre-ringing as the new jitter; striking fear in the hearts of placebophiles.

Ah, it's all good :-) 

I was looking at it more from a mathematical PoV.

Just so you know, I'm not a "true believer" about ringing.
Personally, I've tried to ABX various filter "steepnesses" and I can't hear it.
But that's just me ...



 

Re: PCM, DSD - Trying to get my head round some basics

Reply #134 –
Quote from: judd on
Just so you know, I'm not a "true believer" about ringing.
No worries, I could tell.
Quote from: judd on
But that's just me
...and just about everyone else who knows something about the nuts and bolts of audio including an understanding of the perception of sound which is something many (most?) computer scientists and engineers (both degreed and ceremoniously titled audio engineers, alike) woefully lack.

Re: PCM, DSD - Trying to get my head round some basics

Reply #135 –
I thought this was a nice example from the 2L site of Cello harmonics popping out of the mix, extending up into the 30-40kHz range.
(It's a bit hard to see in a static screenshot; easier to spot on live display)

This is a nice change from the familiar 20kHz roll-off you see all-too-often in many other hi-re$ files.
image link

from the 96kHz version of "North Country II" at around 3:54.3 (unfortunately, DSD version is not available for comparison)

Of course, I don't claim to be able to hear any of the ultrasonic stuff, but it is interesting to see some actual (music-related) ultrasonic material in there - even though the high-frequency components are at pretty low amplitudes.

Re: PCM, DSD - Trying to get my head round some basics

Reply #136 –
Just to play devil's advocate, are we sure the harmonics actually emanated from the cello or could they have been the result of non-linear distortion somewhere in the signal chain?

Re: PCM, DSD - Trying to get my head round some basics

Reply #137 –
Quote from: greynol on
Just to play devil's advocate, are we sure the harmonics actually emanated from the cello or could they have been the result of non-linear distortion somewhere in the signal chain?

yeah, it could be distortion. Who knows ? 
I think they are using some pretty nice mics, though, so i suspect it could be the real deal.
Some mics, (like an Earthworks QTC-50) can capture those frequencies.

It definitely correlates nicely with that particular Cello note, if you watch/listen at the same time.
I was looking for a solo example of one of the brighter-sounding instruments to isolate it, but so far I haven't come across a solo Cello passage yet.
 

Re: PCM, DSD - Trying to get my head round some basics

Reply #138 –
Real or not, I can't hear that. But of course I can set the playback speed to 48k and listen to them in an octave lower and in half speed. ;)

Re: PCM, DSD - Trying to get my head round some basics

Reply #139 –
Quote from: bennetng on
Real or not, I can't hear that. But of course I can set the playback speed to 48k and listen to them in an octave lower and in half speed. ;)
Haha - I've done that too.
Sometimes I completely filter out the audible spectrum first, and slow down what's left :-)

Re: PCM, DSD - Trying to get my head round some basics

Reply #140 –
Quote from: bennetng on
Real or not, I can't hear that. But of course I can set the playback speed to 48k and listen to them in an octave lower and in half speed. ;)
So the stuff at 40k would then be at 20k but still well below your threshold of hearing at those frequencies, assuming you still have the hair cells to detect them. ;)

Re: PCM, DSD - Trying to get my head round some basics

Reply #141 –
 Quarter-speed  ? :D

Re: PCM, DSD - Trying to get my head round some basics

Reply #143 –
Only thing missing in this thread now is why to wurry about dsd and alike when the best ears in this world know only de-blurred MQA sounds right...
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Re: PCM, DSD - Trying to get my head round some basics

Reply #144 –
Quote from: Wombat on
Only thing missing in this thread now is why to wurry about dsd and alike when the best ears in this world know only de-blurred MQA sounds right...

Well after all. everyone knows that MQA "delivers fuller, more tonally satisfying bass notes and a better sense of the space surrounding [Ella] Fitzgerald’s voice" :D

Re: PCM, DSD - Trying to get my head round some basics

Reply #145 –
...and a fuller spectrogram

Re: PCM, DSD - Trying to get my head round some basics

Reply #147 –
Lossy is fine as long as it's MQA certified ;)
.halverhahn

Re: PCM, DSD - Trying to get my head round some basics

Reply #148 –
Quote from: Case on

Any resampler could compensate for the delay. It's just a matter of dropping the extra silent samples.

In my book, careful examination of the files being ABX'd is a natural part of the work flow for preparing the experiment.

The basic influences that most often need to be controlled are:

(1) Level   goal: +/- 0.1 dB

(2) Frequency response: +/- 0.1 dB 20-20K

(3) Time offsets +/- 100 uSecc

Level and time offsets are easy enough to check and correct with any of a large number of audio editors.

Measuring and correcting frequency responsemay be non trivial. One shortcut is to run the Audio Rightmark test file and then evaluate it.  IOW. append the Rightmark test file to the beginning or end of the test file, run it through your test process, and then edit it out and test it with the Rightmark program.

These are what I would call "Best practices" numbers - goals that ensure very unambiguous results.

You may  need to compromise them, but then the compromise should be tested all by itself to ensure that it is not an audible influence in context.

Re: PCM, DSD - Trying to get my head round some basics

Reply #149 –
Jumping back to my pressed/burned CD "anecdote", now that I know a (little) bit more about PCM, I am willing to accept that a digital data misread could not alter a soundwave (yay!).
Any difference could also have been in my imagination (shock horror!).

Out of curiosity, though, for those folk who know about such things, is there any way (perhaps a badly designed power supply?) that a laser head fighting to read a mistracked disc, or power fluctuations due to spin speed alteration for the same reason may have any effect on an outgoing analogue signal? (more so with 30-year old CD players?).

Yes, I'm clutching at straws in the hope that my youth wasn't quite as misguided as it looks like it might have been...  :-[