[LAU] Motu 1248 - Full success

Moshe Werner moshwe at gmail.com
Sat May 13 22:38:33 UTC 2017

On Fri, May 12, 2017 at 10:03 PM, Fernando Lopez-Lezcano <
nando at ccrma.stanford.edu> wrote:

> On 05/11/2017 12:17 PM, Moshe Werner wrote:
> Latency - The latency in CC mode is better than my Firewire interface,
>> but still a bit worse than the rme. For now I succeded to run a medium
>> session (25 Channels with processing and fx) at 64 frames buffer size
>> with 3 buffers.
>> Certainly not bad. While playing guitar and singing I didn't feel any of
>> this annoying delay that you sometimes get when the latency is bad.
> Make sure you are running threaded irq's and that the irq that handles the
> usb connection is running with "soundcard priority". That helps a lot
> (maybe you are already using rtirq and is doing that for you). And, if you
> can, make that the only device that is attached to that particular usb hub.

Thanks for the tips. I just got the interface last week and am still
learning it and how it works with my laptop.

> The channel count is huge for my terms. 64 in and out... That should be
>> enough for me. Though I didn't get around to check if the AVB connection
>> does really work on Linux.
> I have never had the time to try to make the whole AVB thing work. Trying
> OpenAVB a while back I managed to get the Motu to sync with the Linux box
> through AVB, but never went as far as getting discovery and streaming
> working (no time). You do need an ethernet interface that has AVB support
> (Intel i210, for example).
> On the other hand I'm working on a big system that uses (for now) USB at
> 44.1/48 with a 64 channel count to interface with computers, and then the
> rest of the I/O going through AVB streams to and from additional boxes (I
> use either an A16 or 24ai as entry points because they support 8 i/o AVB
> streams). Pretty neat with all the routing matrices shuttling samples back
> and forth. You have to pay attention to how many AVB streams each card can
> handle (they are not necessarily symmetric).

That's great news that AVB is working on linux too!
Could you elaborate on the connection scheme of your setup? Are the
different Motu boxes connected via the AVB switches?

> To summarize I'm feeling that we are moving in the right direction here...
>> I hope other manufacturers will follow and make Interfaces and software
>> that work with Linux...
> I found one issue when using Jack. When you use the interface for the
> first time, or when changing sampling rates, the interface takes up to 7
> seconds to actually change sampling rate and get in sync with others or
> itself. During that time Jack will not start successfully ("cannot set
> hardware params"). The trick so far is to be patient, wait the required
> time, try again and things just work.

Had the same issue! Thanks for pointing that out.
Basically I couldn't explain why at first Jack doesn't launch and then
suddenly everything is ok:)

> The A16 works, as well as the 24ai and 24ao.

That's also great news!

> I had problems with the newer generation of Motu cards that have a USB3
> interface, so beware. Those work fine with USB2 connections but then the
> I/O is restricted to 24 channels input and output (in the older generation
> and with the latest firmware you can select whether you have more channels
> and less sampling rate options or visceversa - that is not available in
> these new cards). If you connect to an USB3 port the USB subsystem in the
> kernel hangs or gets really confused. Reboot time :-(

That's not so great news:(
Why get it right just to do it all wrong again...?
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