On 28/01/2022 19:35, Paul Davis wrote:
On Fri, Jan 28, 2022 at 11:12 AM Len Ovens <len@xxxxxxxxxxxxx
<mailto:len@xxxxxxxxxxxxx>> wrote:
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.
I can use my MOTU USB device at 64/2.
Interestingly I used to be able to get 64/2 with my USB audio devices
(both a Scarlet 2i2 and a Behringer UMC202) on my previous laptop which
was just a 'consumer' Acer I got in 2013, with a realtime kernel, CPU
set to 'performance' mode and disabling WiFi. I was even able to do
128/2 with the internal sound-card.
On my current machine which is a Tuxedo laptop (obviously with more
horse-power in terms of CPU and RAM), I cant seem to go below 128/2
whatever I do. CPU here is managed by proprietary software (well
especially the fans, otherwise they are always on), which kinda sucks
for this kind of machine.
It's really hard to understand if it's the hardware, the (new) kernels,
some other software or OS thing or a mix of all those.
128 is still tolerable for recording and things like Jamulus (which of
course introduces a bit more latency), but yes, for software effects and
processing of live input 64 would be nicer.
In both cases there is one specific USB port which works best with audio
interfaces.
I passed that Acer laptop to my son after upgrading the hard disk to SSD
and adding some RAM and he is still happily using it (albeit the
keyboard and other parts are quite a bit bashed by now and the battery
is dead), so overall it was pretty good buy (8+ years for a laptop isn't
bad).
What I really find frustrating is that the whole usb audio interface
chain is near to impossible to 'debug' as there are so many factors and
so many set-up specific variables.
What's also frustrating is that, intuitively, there should be the CPU,
RAM, USB bandwidth to have pretty low latencies at least for a 2x2
simple set-up.
Lorenzo
There is also the problem with usb devices that the latency changes
every
time the audio device is opened by software.
Apparently now fixed (or certainly much better) in recent kernels.
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.
thunderbird (aka "PCI.? bus on a cable") is presumably the right answer.
but that's just a reminder that the proximal issue here is "what
connections does my laptop provide?"
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