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Justin Ulysses Morse
 
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Default 16 bit vs 24 bit, 44.1khz vs 48 khz <-- please explain

Garthrr wrote:

Following this analogy -- and I just know I'm gonna be wrong here but this is
just how it seems to me -- if we say, for example, that 16 bit audio is like
having a pocket full of 10 dimes then isnt 24 bit audio a pocket full of 100
pennies? Finer divisions of the same whole--the ability to describe finer
voltage differences?


Yes. For the sake of discussion, let's say you have a thousand dollars
in either dimes or pennies.
Now, say you're going to make a single purchase of something that costs
$1.87. At 16 bits, you're forced to tell the clerk to "keep the
change" because all you have are dimes. No big deal, you're out $0.03.
You'll never miss it. Most of us wouldn't bother stooping to pick up
three pennies. But suppose you're going around town buying a whole
bunch of different things, and every time you do, you have to say,
"keep the change." Eventually, it starts to add up and you wish you
had some pennies.

Suppose you record live to 2-track at 16 bits and you just make a
single "transaction" where you maybe run an EQ, a gain boost, and a
little peak limiting all in one pass. You're using 24-bit DSP but you
have to stuff the result back into a 16-bit package. Not a real big
deal, your "clerk" rings you up and says that'll be $45.58. You only
have to say "keep the change" once.

But now what if you've got a bunch of different processes to run,
incrementally, that you evaluate before you move on to the next
process? Maybe you're multi-tracking and you're processing each track
differently. There's all kinds of "keep the change" adding up. In
fact, it's not only "adding up" but it's also "multiplying up." The
error in your first process will get multiplied in your next step. I
guess that would be something like if you bought 1000 of something that
should cost $0.13 apiece but since you're paying in dimes you're paying
$0.20 apiece. Suddenly you're out $70. Your accountant is gonna be
****ed.

This is why more processing means you should start with more bits. But
you know, decimal places on a calculator is probably a better analogy.
Should I start again?

ulysses


I understand that the dynamic range increases with higher bit depth and I
guess
in this money analogy we could think of that as having a dollar fifty or
something instead of the original dollar but it still seems like you get finer
resolution even in the first dollar.

Is this question not analogous to the number of pixels in a digital
photograph?
The more pixels, the higher resolution the picture (all else being equal).
That
being analogous to bit depth in audio then the rate of frames per second in a
moving picture would be analogous to sample rate. Is that a reasonable
comparison?

Sooner or later I'll phrase this question in enough different ways as to
clearly communicate what I want to ask!

Garth~


"I think the fact that music can come up a wire is a miracle."
Ed Cherney