28 Jan
2022
28 Jan
'22
8:11 p.m.
On Fri, 28 Jan 2022, ycollette.nospam(a)free.fr wrote:
I now that there is a big problem of JACK playback
with RT kernels 5.15 and 5.16 ...
JACK and Pipewire use ALSA to talk to the audio device. JACK is capable of
stable operation at least to 16/2 _IF_ the hardware (both audio device and
the computer) are capable of it.
Maybe this card is not yet supported too by pipewire
...
As above, if the device shows up in ALSA, it is already "supported".
However, as a USB device it is competing with all other USB devices and
newer kernels do not show interrupt processes as usb1, 2, 4, etc. In fact,
they tend to group all usb 1.1 and usb 2.0 to one usb port anyway. As
such, the only way to have a separate irq or irq process to prioritize, is
to install a separate PCIe USB card just for that audio device (good luck
with a laptop). The irq for that usb card can then be prioritized.
The audio world seems to have given up on latencies with buffer sizes any
lower than 256/2. Certainly, most recording can be done at even higher
latencies with external monitoring but the use of softsynths or software
effects that require low latency monitoring from the computer is difficult
at best.
There is also the problem with usb devices that the latency changes every
time the audio device is opened by software.
The computer audio world lost when the audio device manufactures jumped
from firewire to usb. Maybe (but don't hold your breath) something will
change in the future. Or look for a PCIe based audio device like the
audioscience cards.
--
Len Ovens
www.ovenwerks.net