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Author Topic: 88.2 or 96?  (Read 1507 times)

J.J. Blair

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88.2 or 96?
« on: December 29, 2004, 04:54:21 PM »
So, I've finally got my HD rig.  I only ever hear about people recording at 96 khz, but if you are eventually going to have to wind up at 44.1 khz (provided you aren't mixing to 1/2"), shouldn't it make more sense to record at 88.2 khz?  I'm blissfully ignorant of the way much of the digital math works, but wouldn't dividing the sample rate by 1/2 sound better than dividing by .459375?  Would somebody who knows how this stuff works please explain it to me and make a recommendation on which sample rate to use?  Thanks.
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They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

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bobkatz

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Re: 88.2 or 96?
« Reply #1 on: December 29, 2004, 05:07:35 PM »
J.J. wrote on Wed, 29 December 2004 16:54

So, I've finally got my HD rig.  I only ever hear about people recording at 96 khz, but if you are eventually going to have to wind up at 44.1 khz (provided you aren't mixing to 1/2"), shouldn't it make more sense to record at 88.2 khz?  I'm blissfully ignorant of the way much of the digital math works, but wouldn't dividing the sample rate by 1/2 sound better than dividing by .459375?  Would somebody who knows how this stuff works please explain it to me and make a recommendation on which sample rate to use?  Thanks.



The issue has come down to the quality of the sample rate converters. A well-designed converter doesn't care if there is an integer ratio, and so, use a well-designed converter. Take a look at the FFTs at the Weiss website, not a hint of any inharmonic distortion, textbook perfect, in a 96 to 44 conversion done on the Weiss. Also, these conversions normally are performed in the mastering suite, which should have an excellent SRC available for this purpose.

You are correct, older or poorly-designed SRCs will cause more problems with non-integer conversions because they do not apply sufficient calculation precision. All of this was described in great detail in Andy Moorer's paper on the subject, which gets a bit hefty in the math, but is effectively summarizable into the above!


BK
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J.J. Blair

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Re: 88.2 or 96?
« Reply #2 on: December 29, 2004, 06:25:56 PM »
Bob, thanks for explaining that.  I have the Apogee DA16X.  Is that UV22HR technology of theirs supposed to be for sample rate conversion?  It's been so long since I've done any D to D, because nobody has brought me any ADATs for years, hence I'm not really hip to the subject.

EDIT: Oops.  I just read the manual, and the UV22HR is for going from 24 bit to 16 bit, not for sample rate conversion.
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They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher

"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham

J.J. Blair

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Re: 88.2 or 96?
« Reply #3 on: December 29, 2004, 11:58:40 PM »
OK, I have a follow up question.  If I'm using PTHD, how would I convert the sample rate using my Apogees, or can I even?  For example, if I do a bounce and tell it to make the file a different sample and bit rate, is that happening in the converter or in the CPU?  

And when I am making reference CDs of mixes , prior to mastering, is it better to record the mix at 96 and then convert or should I just record straight to 44.1?  
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They say the heart of Rock & Roll is still beating, which is amazing if you consider all the blow it's done over the years.

"The Internet enables pompous blowhards to interact with other pompous blowhards in a big circle jerk of pomposity." - Bill Maher

"The negative aspects of this business, not only will continue to prevail, but will continue to accelerate in madness. Conditions aren't going to get better, because the economics of rock and roll are getting closer and closer to the economics of Big Business America." - Bill Graham

Bob Olhsson

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Re: 88.2 or 96?
« Reply #4 on: December 30, 2004, 10:57:54 AM »
The conversion in Pro Tools isn't very good and in "bounce" mode needs to be done to 24 bit and only then dithered to 16. Just coming out analog to a 44.1 recorder is probably the best way short of buying a conversion box.

As for 88.2 vs 96.1, this depends on what gear is being used to master it. My choice would be 88.2 because I haven't heard 96 sound any better and some popular mastering gear, namely Pacific Microsonics, sounds better at 88.2. Theory is great when talking about potential quality but my position is that the end results will mostly be determined by specific implementations.
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neil wilkes

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Re: 88.2 or 96?
« Reply #5 on: January 01, 2005, 09:21:26 AM »
It is perfectly possible to convert from 96KHz to 44.1KHz without using fractions, but entirely in whole numbers.
All you do is use the Greatest Common Denominator to find out the required ratios, which is 300.
So, to convert from 96KHz to 44.1 KHz you simply upsample the 96KHz by a factor of 147, then downsample by a factor of 320.
96000 x 147 = 14112000. Divide this by 320 and you get 44100.

There is at least one SRC that works this way, using whole numbers only:
Voxengo R9Brain Pro.
www.voxengo.com/downloads will get you a demo version. This also has the added bonus of 2 methods of conversion:
1/. Linear Phase mode - the usual digital method, and
2/. Miinimum phase mode, which approximates, and extremely well & closely, the effect of going through seriously high quality DAC then another ADC to do the job.

Sorry to be a pedant, but the myth that you cannot use whole numbers to go from 96 to 44.1 really should be put to bed for once and all.
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