[LAU] MotU Ultralite AVB observations.

Max abonnements at revolwear.com
Sat Mar 7 15:22:58 CET 2020

It would be great to use some kind of wiki to collect all this 
information on one place. I have a MotU 624 AVB and most of what is 
wrote about the Ultralite applies also to this model.

On 07.03.20 13:28, John Murphy wrote:
> Getting my Ultralite AVB working on Linux Mint 19.3 has been quite
> a struggle and I've learnt a few things along the way, which may
> save others some wondering.
> Ignore any thoughts of USB power management causing any issue.
> The device never uses any USB power, as confirmed with an inline
> USB V/A meter.
> Firmware more recent than 1.3.2+520 suffers from the 'bitcrusher'
> effect, where audio can be heard for about 30 seconds, until it
> fades to junk while appearing on higher number channels, until
> it does the same again. That firmware is pre Touch Consoleā„¢.
> Firmware and release notes in the Ultralite AVB section here:
> https://motu.com/techsupport/technotes/firmwarechangelog
> A great deal of good information over at the Linux Musicians forum:
> https://linuxmusicians.com/viewtopic.php?f=6&t=18046
> (Thanks to Eric Schoster for pointing me to that one.)
> One gem is that it can be set to class compliant mode with:
> curl --data 'json={"value":"UAC"}' IP address/datastore/host/mode
> curl --data 'json={"value":"24"}' IP address/datastore/host/maxUSBToHost
> (Replace "IP address" with its address on your network)
> Change to its proprietary mode with:
> curl --data 'json={"value":"USB2"}' IP address/datastore/host/mode
> curl --data 'json={"value":"64"}' IP address/datastore/host/maxUSBToHost
> On my current hardware (i7-8700K) the Ultralite takes 27 seconds
> from first light in the display to showing detail in the display
> and there's a further 20 second delay before any activity shows
> up in a terminal window running 'tail -f /var/log/syslog'.
> There are very many messages like:
> 'clock source 1 is not valid, cannot use'
> Yesterday I was seeing 240 of those in blocks of 40, with each
> block followed by:
> '[pulseaudio] module-alsa-card.c: Failed to find a working profile.'
> and etc.
> Today, after trying the latest firmware, seeing the bitcrusher
> effect and reverting to 1.3.2+520 again, I only see two complete
> blocks and the reporting stops about half way through the third
> block. Qjackctl will then start the server, on either hw:AVB or
> hw:AVB,0. It always seems to need changing to the one of those
> it isn't set to. :)
> I can only think that my dual booting and using it on Windows 10
> caused the trouble I was seeing when using it on Linux afterwards.
> I still can't use anything which isn't 'jack aware', but I can
> live with that, for now. VLC offers 13 'Ultralite AVB, USB Audio'
> devices to chose from, including "Direct sample snooping device".
> Linux, generally, doesn't seem to maintain an optical output if
> a player app stops playing...

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