Subject: Re: [linux-audio-user] terratec aureon 5.1 usb and jack
From: Lee Revell (rlrevell_AT_joe-job.com)
Date: Fri Sep 17 2004 - 22:27:24 EEST
On Fri, 2004-09-17 at 14:44, Sebastian Gutsfeld wrote:
> | loading driver ..
> | apparent rate = 48000
> | creating alsa driver ... hw:1|hw:1|256|2|48000|0|0|nomon|swmeter|-|16bit
> | control device hw:1
> | configuring for 48000Hz, period = 256 frames, buffer = 2 periods
> `----
>
256 frames at 48KHZ is a period time of ~5ms. This is really pushing it
for a USB device. It might work with a low latency kernel.
> Kernel 2.4.25 with CAT_SETPCAP patch but no low latency patch.
>
This is no good. You *need* a kernel patched for low latency.
> BTW, I have no crackling sound using jack with the Intel. Hopefully
> someone can help me with my problem.
>
A PCI card is several orders of magnitude faster than USB. Best case
interrupt response latency with USB is about 1ms. With PCI it's about 5
usecs. Regardless, since you aren't running a low latency kernel, you
will get xruns triggered by random system activity.
Lee
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