On 23.11.20 14:55, David Kastrup wrote: > David Kastrup <dak@xxxxxxx> writes: >> Giso Grimm <gg3137@xxxxxxxxx> writes: >>> On 23.11.20 02:03, David Kastrup wrote: >>>> "Jeanette C." <julien@xxxxxxxxxxx> 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. >> >> Very good to know, thanks! I'll also take a look at the rest of your >> tests. > > 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? 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). > 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 _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx https://lists.linuxaudio.org/listinfo/linux-audio-user
