[LAU] Pro Audio? OT rant.

Thomas Vecchione seablaede at gmail.com
Sun Dec 23 17:30:37 UTC 2012

On Sun, Dec 23, 2012 at 5:45 AM, Fons Adriaensen <fons at linuxaudio.org>wrote:

> Some people believe the strangest things. That doesn't make those
> things true.
> SRC amounts to applying a low-pass filter. That's it. There is no
> other magic involved. The fact that this filter is producing output
> samples at a rate which is different from the input sample rate does
> not change it in any fundamental way. It just means using different
> coefficients, which are no better or worse than those used by a 1:1
> rate filter.
> The operation will add some round-off noise, but no more than a simple
> EQ or even a fader. That noise will be at a level at least 40 dB below
> what will be added by reducing to 16 bit for a CD. Which means it makes
> a difference of less than 1/1000 of a dB, if anything at all. It does
> not add distortion or degrade the signal in any way. If you're looking
> for that, you'll get a zillion times as much by using even the simplest
> dynamic effect.
So I refer you right back to exactly what I said, though, which adds more
noise?  Recording at 44.1 and not doing a SRC (Assuming that the audio
interface of course handles it as well as 48k) or recording at 48k and
downconverting to 44.1?  This is an honest question as I am assuming you
know more about this than I do.  How does this carry through when dealing
with 40-80 tracks of material, all undergoing said SRC before being mixed,
normalized, and dithered down from there?

> Given that most audio interfaces will perform better at 48 kHz than at
> 44.1, if there is any significant difference at all you're probably better
> of producing a CD at 48 kHz and converting it to 44.1 right at the end of
> the chain, the same place where you reduce to 16 bit and add dithering,
> for example in Ardour's export dialog.
> There is no good reason to use 44.1 kHz *ever*, except for the signal
> stored on an audio CD.
There is limited reason not to though considering the limit of our
undamaged hearing is still well encompassed by it.  Mind you I tend to
record in higher sample rates anyways for various reasons, but often times
I am restricted to 48k vs 44.1 in many devices (Multitrack recorders,
digital output rates, etc.)

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