Re: Real World Significant Sources of (what we usually call) Latency

On Mon, 30 Nov 2009 14:14:20 -0500, Mike Rivers <mrivers@xxxxxxxxxxx>
wrote:

If you don't change the buffer setting, IT WILL STILL BE 10 MS!

That's what I suspected - the buffer size is the big elephant in the
room. I'm
sure that the actual latency is the buffer size expressed in time at the
given
sample rate plus whatever other delays there are besides buffering. But
you're suggesting that these "other" delays are insignificant in terms of
input-to-output time.

Isn't an elephant something everyone knows, but no-one admits?

Leaving that term aside - surely it's basic knowledge there's a user
setting for buffer size, and it defines the latency figure? What gets
overlooked is that effective latency isn't this buffer divided by
sample rate. You have to add the fixed figure from the "other"
delays. (This is the couple of ms in "direct monitoring" that Mike
definitely doesn't find insignificant in practice.) The buffering that
causes it is hard-wired into the soundcard architecture and its
drivers.

It's not inconceivable that a user could hack some of these settings.
Rather as we now have to tell Windows System Restore: "Yes, 15% of
the drive was a reasonable amount to use of a 60GB drive, but I think
we can specify rather less of a 1TB disk!", perhaps, on a really fast
computer, the fixed latency could be pared down a little. Or maybe
it's more about the soundcard hardware and should be left well alone.

Anyone else remember struggling to get Cubase Audio running on an
Atari Falcon? The driver that made this possible was unstable with
its default settings. Finding the undocumented setting that cured it
wasn't exactly hacking, but it felt like it in those days!
.

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