[linux-audio-user] Edirol UA-25: Any issues?
clemens at ladisch.de
Fri Nov 18 07:11:03 EST 2005
Cesare Marilungo wrote:
> > Clemens Ladisch wrote:
> >> The theoretical limit of USB 1.x is 12 Mb/s (i.e., 1,500,000 bytes/s).
> >> The Audigy 2 NX can do eight channels with 16 bits at 48 kHz (750 KB/s),
> >> but full duplex stereo with 24 bits at 96 kHz would need 1125 KB/s which
> >> is too much considering the protocol overhead.
> I still have some doubts. 24bits at 48 kHz full duplex in stereo is
> 4.8Mb/s which is less than half the total theoretical bandwidth.
Yes, at 48 kHz it would work.
> But we're talking about something that must be realtime without loosing
> anything. How does latency relate to this?
The USB host controller will send one packet per millisecond in hardware.
The latency depends on whether the computer is able to schedule your program
with a delay small enough so that it can write more data to the buffer in time.
> Anyway do you have experience with this Audigy NX?
No, only with the Audigy 2 NX. ;-)
> What about the latency?
Like any other USB audio device. It depends on your computer.
On my machine, I can get about 2 ms (without anything else running), but I
didn't test much.
> My brother has an older Audigy (PCI not USB)
PCI is completely different.
> and with the original drivers he get 1sec of latency (300ms in + 700out).
I hope you are not speaking about snd-emu10k1 here ...
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