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  #1  
Old 06-18-2003, 07:47 PM
muspro muspro is offline
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Default High Sample Rate Debate

Hey guys,

We have a deep discussion going on the the PTLE forum. Any tech heads want to chime in? It is unfortunately under "Digi 001 Discontinued?"

We are debating if higher sample rates yeild greater resolution to a recording. As in more accurately representing the original analog waveform.

One theroy is that according to the Nyquist Theory that at 44.1 kHz ALL frequiencies under 20k is reproduced PERFECTLY and EXACTLY like the original analog wave form. No questions asked.

My theory is that higher SR equals higher resolutions and more accurate representations of analog waveforms.

I have posted a diagram at: www.star-studios.com

It is under DIGITAL PIC on the left hand side. Take a look and give your opinion on the other forum.

Thanks!
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  #2  
Old 06-19-2003, 05:46 AM
masmit masmit is offline
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Default Re: High Sample Rate Debate

Quote:
Originally posted by muspro:

One theroy is that according to the Nyquist Theory that at 44.1 kHz ALL frequiencies under 20k is reproduced PERFECTLY and EXACTLY like the original analog wave form. No questions asked.

My theory is that higher SR equals higher resolutions and more accurate representations of analog waveforms.
<font size="2" face="Verdana, Arial">Well, as I understand it the Nyquist theory is pretty unarguable, the debate about high SR being really about a) the effects of decimation filters in ADs and b) whether or not information above 20Khz is useful.

Do a search for any threads involving Nika, and you will probably find debates that will more than satisfy your curiosity...


Cheers, Mark
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  #3  
Old 06-19-2003, 08:01 AM
roberts roberts is offline
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Default Re: High Sample Rate Debate

I have recorded sesssions @ 192k and the results are fantastic. I am always tracking @ 96k and mixing to 44.1k. It is a vast improvement in the detail.
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Old 06-19-2003, 03:24 PM
jackruston jackruston is offline
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Default Re: High Sample Rate Debate

It is often debated.

As mentioned above search for posts by Nika. He's the real guru for all this stuff.

IMHO its easier to make a 96k converter that sounds good than a 48k. If you dont have to worry so much about the filtering or whatever it is because its going on up in the 48khz zone or even 96khz for the 192 rate, then it must surely make life easier. A converter that sounds brilliant at 48k is a truly great converter, but a 96k converter that sounds truly great could just be merely decent and well designed.

I'm not refering to digi products there. As it happens the 192 sounds really good at 48khz...much better than the 888 24 ever did for me. I'm not saying its the best thing on the planet, but its priced really well, and if you cant get a great sounding recording out of an HD rig, your problems lie elsewhere.

J
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  #5  
Old 06-19-2003, 03:49 PM
Mark Wheaton Mark Wheaton is offline
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Default Re: High Sample Rate Debate

It just seems common sense that higher sample rates means more samples per wave form at any frequency. More samples means closer representation of analog waveform. There is all sorts of math tricks that make 44.1 work as well as it does but bottom line would seem if you have a 22KHZ sample for instance, there are two points on that waveform that get sampled at 44.1, the waveform is then extrapolated from that. at 11KHZ that would mean four samples. If it were 96KHz then at 11K there would be more than 8 samples, therefore a much greater detail of the actual waveform that would get extrapolated. I would love to hear from true experts whether this simplification is accurate. I think it is.
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  #6  
Old 06-19-2003, 04:20 PM
masmit masmit is offline
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Default Re: High Sample Rate Debate

Suffice it to say that this stuff is quite counter-intuitive. Stop imagining that a DtoA simply draws straight lines between samples. It just doesn't work that way. A DAW may represent things that way on the screen, but the DtoA is doing something completely different.

96k gets you one more octave of HF (192 gets you two), and a maybe an easier to design and implement anti-aliasing filter, but it doesn't get you better 'resolution', however much you prefer the end result.

I am not enough of a physicist to even begin explaining the mathematics involved, but there are those here who are, from the Digidesign engineers through to Nika and other very bright individuals.

I wonder if anyone here has a link to a clear explanation of Nyquists theorem for dummies. Anyone?


Cheers, Mark
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  #7  
Old 06-19-2003, 04:41 PM
digiengineer digiengineer is offline
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Default Re: High Sample Rate Debate

Fs/2=x kHz

x=Highest Theoretical Frequency Reproduced
Fs= Sample Frequency or Sample Rate

i.e. 44.1 kHz Fs=22.05 kHz
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  #8  
Old 06-19-2003, 04:58 PM
lancejorton lancejorton is offline
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Default Re: High Sample Rate Debate

i thought the issue was mainly with editing/mixing/conversion... not sound quality of an individual track... that editing or mixing a 88.2kHz is more accurate than editing or mixing a 44.1kHz because the software has more samples to work with. i assume that's why new plug-ins like the Massenburg EQ internally upsample to 88.2kHz/96kHz before editing.

i have a friend who does professional mastering and before HD, he would upsample with a Weiss box to 88.2kHz before going to a Weiss D/A and then to his analog outboard chain of EQs/compressors. of course, he would go the opposite path on the way back into his old mix system. again, the idea being that editing or conversion of the signal is more accurate at higher sampling rates... not the sound quality of an individual track.

just my thoughts. am i totally off base?

lance
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  #9  
Old 06-19-2003, 05:23 PM
Charles D. Ballard Charles D. Ballard is offline
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Default Re: High Sample Rate Debate

A few more things to consider:

1. To truly gain the benefit of higher sample rates, you must use analogue gear that can also support those frequencies. Granted, most high-end pro gear will, but you should still be careful.

2. Pitch-shifting. That, IMHO is where the greatest advantage of higher sample rates lies. If you use a source recorded at 44.1 and pitch-shift it down by one octave, everything above 10k is gone. Higher sample rates preserve more of the harmonic structure.
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  #10  
Old 06-19-2003, 05:44 PM
PMoshay PMoshay is offline
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Default Re: High Sample Rate Debate

Too bad it all dosen't mean much when music is now distributed online.

You all should be concerned that Apple/Dolby have adopted the AAC format as the new future of music distribution.
As the new Macworld magazine "AAC is a vast improvement over the mp3 format"
Funny, i and many respected colleges did various listening tests comparing AAC, mp3's @192, and 16bit cds and found that AAC was the worst of the 3 sounding formats. Not only did the air get lost, the high end was very compomised and the mixes were overall more compressed.

I know that Dolby and Apple are very respected and funded companies, and that technology and security of AAC as a distribution format is great, but to make a blanket statement that it "sounds better than mp3" or is "CD quality" is just a LIE.
If you notice in any of the press or articles touting the greatness of the AAC format, there is never a professional engineer or producers endorsement.

I have sent many emails to Apple about this, with no replies.

All you engineers out there, do a test of some music with a nice open dynamic range and see for yourself.

In itunes 4.01-
(import settings can be changed each time in the preferences-importing tab-re-name each import with the samle rate)
1. import a song at 16bit wave or aiff
2. import the same song at mp3@192
3. import AAC @128k
4. take a test listen for yourself.........

speak up and voice your opinions or audio will soon be reduced to telephone "CD" quality.
People do listen to audio professionals and spread what you say out to the public, don't let Apple and Dolby give the public bogus info just because it helps their cause.....

Thats my rant......somebody pick it up from here......
[img]images/icons/grin.gif[/img]
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