R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2 3 ... 39   Go Down

Author Topic: The sampling rate debate, from a different perspective....  (Read 93326 times)

Andy Simpson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 714
The sampling rate debate, from a different perspective....
« on: September 15, 2005, 04:22:13 pm »

-- I posted this over on Gearslutz, in a '192' debate, but I guessed most of you guys are too high class for that joint, so I pasted it here too --

Ok guys, how about this perspective:

In spatial terms, if 20k has a wavelength of 1.7 cm, then perhaps higher sampling rates can help us better represent the spatial timing differences in sounds.

Or, specifically, a recording made at 44.1 will 'quantize' the spatial timing aspects of a recording into chunks of 1.7cm.

When you think of the scale of a drumkit, cello or guitar, 1.7cm sampling seems rather crude.....Imagine a cello made of sugar cubes....pretty low resolution in my book.

Or imagine the round edge of a snare drum, quantized into 1.7cm blocks....not very round!

The strings on a guitar are often closer together than 1.7cm!

I'm not just talking left-right here, but front-back too.

In these terms, analogue tape really kills digital, but one can see in very real terms just how higher sampling rates might improve this aspect of imaging (ie. realness - and I would expect 192 to sound much more REAL than 44.1, where 1.7cm becomes 0.17cm - but I'd reckon on needing MUCH higher rates for really real sound).

Also (a small digression), these sorts of measurements start to make sense of the anti-NFB argument, where negative feedback can actually start to make spatially measureable distortions.

Andy
Logged

jimmyjazz

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1885
Re: The sampling rate debate, from a different perspective....
« Reply #1 on: September 15, 2005, 04:27:43 pm »

andy_simpson wrote on Thu, 15 September 2005 16:22

In these terms, analogue tape really kills digital


How so?  Analog tape has the same ~ 20 kHz bandwidth, on a good day.

I think your reasoning is flawed, too.  You're mapping the wavelength of sounds in air to structural "quanta" of instruments, but the wavelengths of those vibrations within the instruments themselves are far different.
Logged

Andy Simpson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 714
Re: The sampling rate debate, from a different perspective....
« Reply #2 on: September 15, 2005, 04:46:19 pm »

jimmyjazz wrote on Thu, 15 September 2005 21:27

andy_simpson wrote on Thu, 15 September 2005 16:22

In these terms, analogue tape really kills digital


How so?  Analog tape has the same ~ 20 kHz bandwidth, on a good day.

I think your reasoning is flawed, too.  You're mapping the wavelength of sounds in air to structural "quanta" of instruments, but the wavelengths of those vibrations within the instruments themselves are far different.



I think that you're missing the point.

It's not bandwidth that digital lacks over tape.
It's the spatial quantization that digital enforces, which can easily be measured in spatial terms (ie. 1.7cm).

To explain further; when you have a stereo signal, the time differences between left/right are limited to steps of 1.7cm by the sampling rate.

I am trying to illustrate that the sound made by acoustic instruments is as complex as their phyiscal shape and that 1.7cm quantization of this is very poor indeed.
This applies to reverb and all other aspects of acoustic sound.

Andy
Logged

Ged Leitch

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1057
Re: The sampling rate debate, from a different perspective....
« Reply #3 on: September 15, 2005, 04:51:28 pm »

I respect the views above but have to point out that SACD with it's higher sample rate has still not convinced many listeners, engineers maybe but general public? no.Thats why CD is still popular.
The point about the crude quantizing of the spatial aspects of waveforms at 44.1khz is interesting though, but remember even though at 192khz this is improved in your theory, then a lot of it is thrown away when we reduce to 44.1khz again for CD.
So do you think it makes THAT much of a difference?
Logged
http://bitheadmastering.co.uk/

"...But I don't wanna be a pirate!"

Andy Simpson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 714
Re: The sampling rate debate, from a different perspective....
« Reply #4 on: September 15, 2005, 04:59:48 pm »

I'm saying that digital is flawed in a way that tape never dreamt of.

I'm saying that I would expect to need massively high sampling rates to provide the same spatial information that good tape has provided for years.

Even 192, at a quantization of 0.17cm, is still inadequate in my view. Probably my ears would be more impressed with something that approaches atomic scale.

Anyway, I would like to submit that this spatial quantization could explain why people can hear the difference and prefer 192 to 96 or 44.1 or whatever, despite a hearing bandwidth of 20-20k......

....but that tape still wins, as the quantization IS atomic level! Wink

Andy
Logged

dcollins

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2815
Re: The sampling rate debate, from a different perspective....
« Reply #5 on: September 15, 2005, 05:00:09 pm »

andy_simpson wrote on Thu, 15 September 2005 13:22

 
Or, specifically, a recording made at 44.1 will 'quantize' the spatial timing aspects of a recording into chunks of 1.7cm.



Not true.  The interchannel accuracy comes from the word-length, not the sample rate.  With dither, there is essentially no limit to the "spatial resoultion."

DC

Andy Simpson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 714
Re: The sampling rate debate, from a different perspective....
« Reply #6 on: September 15, 2005, 05:21:05 pm »

dcollins wrote on Thu, 15 September 2005 22:00

andy_simpson wrote on Thu, 15 September 2005 13:22

 
Or, specifically, a recording made at 44.1 will 'quantize' the spatial timing aspects of a recording into chunks of 1.7cm.



Not true.  The interchannel accuracy comes from the word-length, not the sample rate.  With dither, there is essentially no limit to the "spatial resoultion."

DC


I disagree.

In terms of the human auditory system, you appear to be talking about interaural _level_ differences.

I am talking about interaural _timing_ differences.

Andy
Logged

Ged Leitch

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1057
Re: The sampling rate debate, from a different perspective....
« Reply #7 on: September 15, 2005, 05:41:20 pm »

[quote title=andy_simpson wrote on Thu, 15 September 2005 22:21][quote title=dcollins wrote on Thu, 15 September 2005 22:00]
andy_simpson wrote on Thu, 15 September 2005 13:22

 

I disagree.

In terms of the human auditory system, you appear to be talking about interaural _level_ differences.

I am talking about interaural _timing_ differences.

Andy



And can you equate these "interaural timing differences" to something we can HEAR and understand?
Logged
http://bitheadmastering.co.uk/

"...But I don't wanna be a pirate!"

Andy Simpson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 714
Re: The sampling rate debate, from a different perspective....
« Reply #8 on: September 15, 2005, 05:58:28 pm »

[quote title=Gerald Leitch wrote on Thu, 15 September 2005 22:41][quote title=andy_simpson wrote on Thu, 15 September 2005 22:21]
dcollins wrote on Thu, 15 September 2005 22:00

andy_simpson wrote on Thu, 15 September 2005 13:22

 

I disagree.

In terms of the human auditory system, you appear to be talking about interaural _level_ differences.

I am talking about interaural _timing_ differences.

Andy



And can you equate these "interaural timing differences" to something we can HEAR and understand?



As far as understanding is concerned, my explanations are as simple as I can manage.

In terms of hearing, good ears will probably help, and having an all-analogue recording chain to compare to digital would be useful.

I'm just trying to explain why I think we should be looking towards higher sampling rates, why we might hear a benefit and why tape (& vinyl) will continue to beat digital until this area is adressed specifically.

Andy
Logged

Norwood

  • Full Member
  • ***
  • Offline Offline
  • Posts: 223
Re: The sampling rate debate, from a different perspective....
« Reply #9 on: September 15, 2005, 05:58:43 pm »

Quote:

I am trying to illustrate that the sound made by acoustic instruments is as complex as their phyiscal shape and that 1.7cm quantization of this is very poor indeed.
This applies to reverb and all other aspects of acoustic sound.


This is absurd.
Logged
Michael Norwood
Wood Bros. Productions

tom eaton

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3640
Re: The sampling rate debate, from a different perspective....
« Reply #10 on: September 15, 2005, 06:00:16 pm »

What instruments do you record where the fundamental frequency is 20kHz?  That's the only frequency represented by your math.  Don't forget that 90% of the musical information in most cases is below 10k.  Now try your math again.

But before you do: How many samples represent a cycle at Nyquist? (Hint: it's not one)

And don't forget to think about oversampling at both converters.

-tom

Ged Leitch

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1057
Re: The sampling rate debate, from a different perspective....
« Reply #11 on: September 15, 2005, 06:02:09 pm »

[quote title=andy_simpson wrote on Thu, 15 September 2005 22:58][quote title=Gerald Leitch wrote on Thu, 15 September 2005 22:41]
andy_simpson wrote on Thu, 15 September 2005 22:21

dcollins wrote on Thu, 15 September 2005 22:00

andy_simpson wrote on Thu, 15 September 2005 13:22

 

I disagree.

In terms of the human auditory system, you appear to be talking about interaural _level_ differences.

I am talking about interaural _timing_ differences.

Andy



And can you equate these "interaural timing differences" to something we can HEAR and understand?



As far as understanding is concerned, my explanations are as simple as I can manage.

In terms of hearing, good ears will probably help, and having an all-analogue recording chain to compare to digital would be useful.

I'm just trying to explain why I think we should be looking towards higher sampling rates, why we might hear a benefit and why tape (& vinyl) will continue to beat digital until this area is adressed specifically.

Andy


Too much maths and science and not enough real world comparisons and expanations to relate to for me so sorry.
cheers.
Logged
http://bitheadmastering.co.uk/

"...But I don't wanna be a pirate!"

Andy Simpson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 714
Re: The sampling rate debate, from a different perspective....
« Reply #12 on: September 15, 2005, 06:10:37 pm »

TER wrote on Thu, 15 September 2005 23:00

What instruments do you record where the fundamental frequency is 20kHz?  That's the only frequency represented by your math.  Don't forget that 90% of the musical information in most cases is below 10k.  Now try your math again.

But before you do: How many samples represent a cycle at Nyquist? (Hint: it's not one)

And don't forget to think about oversampling at both converters.

-tom




The fundamental frequency of a sound does not affect it's origin.
My taking of 20k is just a round number for the sample rate.

My whole point is that a 1k sound can be made at any distance from a mic (or two).

This distance affects the time of arrival.

According to the sampling rate, the time of arrival will be quantized.

I can't make this any simpler folks.

Andy
Logged

dcollins

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2815
Re: The sampling rate debate, from a different perspective....
« Reply #13 on: September 15, 2005, 06:11:25 pm »

andy_simpson wrote on Thu, 15 September 2005 14:21



I disagree.

In terms of the human auditory system, you appear to be talking about interaural _level_ differences.

I am talking about interaural _timing_ differences.




So am I.  And it's as non-intuitive as they come!

DC

Ged Leitch

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1057
Re: The sampling rate debate, from a different perspective....
« Reply #14 on: September 15, 2005, 06:16:58 pm »

[quote title=andy_simpson wrote on Thu, 15 September 2005 23:10

I can't make this any simpler folks.

Andy[/quote]

Ok so if you can't make it simpler can you at least tell us how this equates to audible differences we are supposed to be hearing?
e.g...
we all know that reducing a 24 bit file to 8 bit will sound terrible as the bitdepth used to represent the audio is reduced and therefore we lose information and get all sorts of unpleasant artefacts.
So, that said can you give us an example of how your theory relates to audible differences we can hear?
Logged
http://bitheadmastering.co.uk/

"...But I don't wanna be a pirate!"
Pages: [1] 2 3 ... 39   Go Up