[LAU] Focusrite Scarlett 18i8

[James Stone]

On Wed, Jan 8, 2014 at 9:34 AM, Tim Goetze <tim at quitte.de> wrote:
> [Jeremy Jongepier]
>>Thanks for the info Robin, I was about to acquire a Scarlett 2i4 but I
>>guess I need to look for other options.
>
> I'd like to add that the 2i4 seems to be pretty much incapable of
> useable low-latency operation in some situations.  Even with buffer
> sizes in the tens to hundreds of milliseconds it produces frequent
> clicks on the same system that runs a UCG-102 at 3x48/48k with no
> problems, a Thinkpad with an Intel chipset, 3.12.5-rt7.
>
> This kernel includes the patch[*] that was recently mentioned in an
> Ubuntu bug report by James Stone on this list, supposedly fixing
> lowish-latency operation of the 2i4.
>

Actually, the linked patch doesn't help at all with the low latency
problems with 3.6+ kernels on the 2i4. However, there have been a
couple of other patches, which should be in the 3.12 branch, which did
help. See: https://bugs.launchpad.net/ubuntu/+source/linux-lowlatency/+bug/1185563

There have apparently been a lot of changes to the handling of usb
devices in the kernel, which may lead to degrading of performance for
a while tho. However, the clicks you report don't really sound as if
they were xruns, so it's a bit odd. I certainly haven't experienced
anything similar.

The latency performance isn't that great on my system (maybe runs OK
at 2/128 at 48k but does get some xruns altho haven't done things like
disable wifi). Interested to know what other people think is
reasonable performance in terms of buffer size for a usb interface?
And recommendations for other similarly priced USB devices that work
well/stably on linux. Seems the 2i4 holds up its price pretty well in
the 2nd hand market anyway - and it is pretty good in terms of build
quality in my opinion.

James