[LAU] Motu 1248 - Full success

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Mon May 15 05:59:24 UTC 2017

On 05/12/2017 11:51 PM, Ralf Mardorf wrote:
> Hi,
> IMO we should get used to USB class compliant devices _even without
> access to the hardware mixer_.

In some cases that is all you need[*].

In the case of the Motu 16A/24Ai/24ao/etc the web interface makes them 
usable for my purpose. Without that, you would need to initialize the 
interface with a different operating system. And you would not be able 
to use the internal routing matrix, and/or multiple devices 
interconnected through AVB. So it is not optional and not having access 
to the internals would make the device useless.

>With my new mobo (elCheapo,as well as
> the CPU, it's just an Intel(R) Celeron(R) CPU G1840 @ 2.80GHz) I noticed
> that even if IRQs are shared with USB and even if it is impossible to
> unbind devices, even if IRQs of some components differ with each
> reboot, low latency without xruns is provided.

Good for you. I did not notice any big problems either. But I'm using 
this in concert performance situations, with the interfaces driving a 
24.8 speaker array for 3D sound. I tried to minimize the chance of 
random interactions between peripherals.

Also, I found upping the IRQ priority for the USB subsystem to be 
essential for good performance. As the USB priority is very high for the 
soundcard I would rather not have the mouse and other stuff running at 
that priority.

-- Fernando

[*] and sometimes it is tricky. We got some Tascam 4x4 for four channel 
use - the default setup folds over the "back" channels to the front so 
that (I guess) monitoring works. Not what we needed. The only way to fix 
that was to initialize the setting on a Mac.

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