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Re: Sample Rate Conversion

Subject: Re: Sample Rate Conversion
From: Walter Knapp <>
Date: Tue, 11 May 2004 21:15:44 -0400
From: "Rich Peet" <>

>
> Audition converts files that are opened to 32bit floating for all
> edits unless you change the default to defeat it.  There is no change
> made on sample rate.

In contrast, Spark XL installs set to run it's scratch files at whatever
the original was. But provides multiple options for setting that in it's
prefs. Once set in it's prefs, it sticks with that setting. I don't
think Spark XL changes the sample rate either.

> I guess I don't understand the benefit of conversion to 192khz
> inorder to make a "big" jump.  I thought math was math to a
> computer.  I guess I will catch up on that as I record more and find
> myself converting more.=20

Actually, computers are fairly inaccurate at math. Not as bad as when I
started and they were doing their math 8bit, but even 32 bit is beaten
by my HP programmable calculator.

In this case going to the high sample rate and back down was found by
trying it. There is nothing magic about 192khz, but I found the greater
the jump the better the result in this case. 192khz happens to be the
highest rate supported by my system. I'm sure it has to do with how the
conversion is being done by Peak and Soundhack. It simply minimizes
errors in the calculations. I leave it up to the programmers of those
programs to explain why.

> Then there is the million dither choices to make on down sampling
> which is a separate nightmare of a choice.

Peak has three settable "power dither" settings, with little explanation
other than what types of recordings best suit each. My peak samples were
all done at power dither 3. I could not tell a lot of difference there,
but maybe because the tricks I did amounted to a type of dithering. Peak
also has other settings that change the dithering, but I'm not that
familiar with them as I do my heavy lifting in Spark XL.

You can go nuts piddling with all possible parameters in these programs.
Especially as best is often a function of the particular material, not
consistent through all recordings.

It's part of the art of learning to use these programs well.

Walt




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