23 Nov
2020
23 Nov
'20
4:50 p.m.
On 23.11.20 14:55, David Kastrup wrote:
David Kastrup <dak(a)gnu.org> writes:
it is based on rumors that with the USB 1.1 audio protocol it latency is
lowest if the fragment size is a multiple of 1ms. I am quite sure that
this was a problem with USB 1.1 devices about 10 years ago.
Whatever jack supports should be fine, with the USB 2.0 devices I don't
see any differences. However, the latencies I measured behave like
4*P + X
where with older cards I have very faint memories of achieving something
like 3*P + Y (although with a longer total delay, at least for short
period sizes).
Giso Grimm <gg3137(a)vegri.net> writes:
Question: is there a reason that you are going with buffer sizes of
3*2^n rather than 2^n? I've not actually tried what Jamulus does in
that situation (but will do) but it seems a bit strange to me. Does it
have some inherent advantage? On 23.11.20 02:03, David Kastrup wrote:
Very good to know, thanks! I'll also take a look at the rest of your
tests. "Jeanette C."
<julien(a)mail.upb.de> writes:
> Nov 22 2020, David Kastrup has written:
> ...
>> So I am lacking a reasonably solid recommendation of (possibly older but
>> reasonably quality) hardware with 1 or 2 mic inputs and +48V phantom
>> power and likely USB2.0 HiSpeed class compliant, possibly 2 headphone
>> outputs
> ...
> Is it worth investigating the Focusrite Scarlett interfaces? I have read
> here - a few weeks ago - that the 3rd generation is now supported on
> Linux. But the 2nd generation is still listed in some stores. The
> Scarlett 2i2 with two mic preamps +48V phantom power costs about 139EUR,
> the solo - with just one mic preamp - is less than 100 EUR . I think
> these smaller Scarletts used to be a favourite with RaspberryPis, as
> well.
>
> I don't know the latency, but many people speak very favourably about
> them.
I recently measured latencies (analog to analog) for some sound cards,
including the Focusrite Scarlett solo 3rd gen (2i2 should be the same):
https://github.com/gisogrimm/ovbox/wiki/Soundcards
From all the USB sound cards I tested the Focusrite Scarlett was the one
with the shortest delay. That being said: I was particularly looking for the
Presonus Audiobox
USB these days (since I guess Presonus cards newer than the lacklustre
Firebox are supposed to have good preamps/gains) but with regard to
latency, it doesn't seem like the greatest choice.
The only Presonus Audiobox USB I have at hand has a broken phantom power
supply, thus I cannot judge the preamps.
Best,
Giso