Ultralite AVB

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pemberley
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Re: Ultralite AVB

Postby pemberley » Sat Feb 09, 2019 1:36 pm

When using JACK, I see 24 in and 24 out. This is the number I specified when configuring jackd (via Cadence), and also the number I picked in the web interface to my 16A. The 16A lets you make available a variable number of channels to the computer. At the sample rate I'm using (96k), it's capable of 32/32, so maybe I'll try that just in case turning off channels is causing issues.

pemberley
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Re: Ultralite AVB

Postby pemberley » Sat Feb 09, 2019 2:11 pm

I just tried it; there seems to be a reason I picked 24. The web interface won't let me select any more than 24 channels, and changes the number I specify to 24 if it's larger. The specs indicate that I can use 32 at 96k, but maybe that's an error. I also tried with 16 channels, and get the same channel hopping issues.

ahellquist
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Re: Ultralite AVB

Postby ahellquist » Sat Feb 09, 2019 2:39 pm

pemberley wrote:I just tried it; there seems to be a reason I picked 24. The web interface won't let me select any more than 24 channels, and changes the number I specify to 24 if it's larger. The specs indicate that I can use 32 at 96k, but maybe that's an error. I also tried with 16 channels, and get the same channel hopping issues.

Motu changed the specifications for the number of selectable usb streams in Class Compliant mode and recent firmwares do not allow more than 24 streams but the documentation and sales information does not mention this AFAIK
There is no mention in the changelogs of this fact either which is strange..

This is the response I got from Motu regarding this regression Sep 19 2017
------------
"That's correct. The latest firmware limited the channel count when using the class compliant drivers. You can only access 64 channels when using the Mac or Windows drivers that we provide on motu.com/download. If you're not looking to use the driver, or are on an OS other than Mac or Windows, feel free to downgrade to the previous firmware.

You can download the file here: http://www.motu.com/techsupport/technot ... changelog/

Go to UltraLite AVB and get version 1.2.8. Next, go to the MOTU Pro Audio Web App and scroll to the bottom of the page to "Update from File" Follow the on screen instructions."
-----------------
This is the reasoning behind the decision:

"
What we were finding was that 64 channels over the class compliant driver was getting too unstable. Unfortunately, I'm not sure if this option will come back. It's been like this for several firmwares. The good news is that we're not taking the option away completely, you'll just need to be on an earlier firmware. All the standard parts of the driver are still there. "
-------------

Sadly Motu is limiting the channel count to mitigate problems for the user even though many people have used more than 24 without problems.
For me as a paying customer I feel the value of my investment is in the hands of a company the same way as if I was using an Apple product and apple suddenly decided to drop support for the hardware I was using. I have urged Motu to make the option available again but since Linux is a non supported platform I guess they simply do not care. :(

This rant is about Ultralite AVB which I have two of and I guess the same applies to other Motu AVB devices but there might be Motu gear that are too new to support going back to older firmware where that still was a supported option.

pemberley
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Re: Ultralite AVB

Postby pemberley » Sat Feb 09, 2019 2:54 pm

Well that's rather unfortunate, but I suppose MOTU is under no obligation to support use of their products on a non-supported OS. For my use cases, I think 24 channels is plenty; maybe that could change though.

I think I'll try reverting my 16A to old firmware. I'm unsure if the channel count issue is even related to the channel hopping one, but it can't hurt. Some of the newer features of the internal mixer and web interface are nice, though working at all is more important.

ahellquist
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Re: Ultralite AVB

Postby ahellquist » Sat Feb 09, 2019 3:09 pm

pemberley wrote:Well that's rather unfortunate, but I suppose MOTU is under no obligation to support use of their products on a non-supported OS. For my use cases, I think 24 channels is plenty; maybe that could change though.

I think I'll try reverting my 16A to old firmware. I'm unsure if the channel count issue is even related to the channel hopping one, but it can't hurt. Some of the newer features of the internal mixer and web interface are nice, though working at all is more important.


I agree that it is not a show stopper but still something that is not documented in their documents and changelogs so more people will learn about this the hard way which is unfortunate.

Hopefully Motu will consider unlocking that setting sometime in the future and be more friendly and just warn the user that more than 24channel might cause problems and the user are supposed to lower the count if necessary. That approach would not give them more support and would not take more than a few seconds to implement. Everyone happy...

Drumfix
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Re: Ultralite AVB

Postby Drumfix » Sat Feb 09, 2019 3:48 pm

You can set the device to Motu proprietary mode by

Code: Select all

curl --data 'json={"value":"USB2"}' 169.254.24.19/datastore/host/mode
curl --data 'json={"value":"64"}' 169.254.24.19/datastore/host/maxUSBToHost


and back to class compliant mode by

Code: Select all

curl --data 'json={"value":"UAC"}' 169.254.24.19/datastore/host/mode
curl --data 'json={"value":"24"}' 169.254.24.19/datastore/host/maxUSBToHost


In the proprietary mode the device uses interfaces 4 and 5 for audio streaming, while in class compliant mode it uses interfaces 1 and 2.
So maybe adding a quirk to the USB driver is already enough to make it work.

pemberley
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Re: Ultralite AVB

Postby pemberley » Sat Feb 09, 2019 4:06 pm

Interesting, I've tried setting my device to proprietary mode in this way. In proprietary mode, audio plays from multiple channels (only assigned to one), and periodically starts and stops, a few times per second. If I switch it back to class compliant mode, the channel hopping is as before: one channel at a time, but it bounces around.

ahellquist
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Joined: Mon Jul 01, 2013 12:28 am

Re: Ultralite AVB

Postby ahellquist » Sat Feb 09, 2019 4:29 pm

Drumfix wrote:You can set the device to Motu proprietary mode by

Code: Select all

curl --data 'json={"value":"USB2"}' 169.254.24.19/datastore/host/mode
curl --data 'json={"value":"64"}' 169.254.24.19/datastore/host/maxUSBToHost


and back to class compliant mode by

Code: Select all

curl --data 'json={"value":"UAC"}' 169.254.24.19/datastore/host/mode
curl --data 'json={"value":"24"}' 169.254.24.19/datastore/host/maxUSBToHost


In the proprietary mode the device uses interfaces 4 and 5 for audio streaming, while in class compliant mode it uses interfaces 1 and 2.
So maybe adding a quirk to the USB driver is already enough to make it work.


Wow, this is really useful and might help making the artificially imposed restrictions go away..

This thread is great for so many reasons..

Thanks for your the knowledge and continuous work to make AVB really usefull some day soon.

pemberley
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Joined: Sun Jan 13, 2019 11:33 pm

Re: Ultralite AVB

Postby pemberley » Sat Feb 09, 2019 4:37 pm

I just downgraded my firmware to v1.1.4+923, and it solves the channel hopping! Unfortunately, though, the audio gets a little crunchy sometimes, which makes it unusable. I'm optimistic this is just a matter of getting the buffer settings right; hopefully soon it'll be solid!

pemberley
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Re: Ultralite AVB

Postby pemberley » Sat Feb 09, 2019 5:02 pm

Alright, this seems to be working with a pretty large buffer (2048 samples, 6 periods) at 24/96; I've patched six channels of outputs to inputs in the analog domain, and configured my DAW to thread a tone through out/in/out/in ... with six OI pairs. I'm going to record the result for about an hour as a test of stability and will get back to you with the results!

murray
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Re: Ultralite AVB

Postby murray » Sat Feb 09, 2019 7:18 pm

pemberley wrote:Alright, this seems to be working with a pretty large buffer (2048 samples, 6 periods) at 24/96; I've patched six channels of outputs to inputs in the analog domain, and configured my DAW to thread a tone through out/in/out/in ... with six OI pairs. I'm going to record the result for about an hour as a test of stability and will get back to you with the results!


Is this with or without the kernel patches? Considering downgrading my firmware.

murray
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Re: Ultralite AVB

Postby murray » Sun Feb 10, 2019 3:37 am

I downgraded to the suggested v1.1.4+923 firmware and I'm not getting any channel skipping.

What issue I did run into was I have a monome 512 which runs over a USB2 connection (running from a hub using 2 FTDI serial converters) and was getting interference in the USB bus of my single board computer. I think it was related to my USB chipset's bandwidth? My Steinberg UR22 was allowing the monome to run fine, but after disabling the 16A's optical banks and limiting the channels to 16 in and 16 out, performance is fine and I'm smooth-sailing.

Thanks folks.

pemberley
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Joined: Sun Jan 13, 2019 11:33 pm

Re: Ultralite AVB

Postby pemberley » Sun Feb 10, 2019 6:29 am

With! I can try it without, if you're interested; I was only running the newest firmware before. The patch and build process is surprisingly not that bad regardless. I had to make a small change of line numbers in one of the patchfiles to get it to work with my distribution of the realtime kernel (Manjaro), which I can share.

Drumfix
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Re: Ultralite AVB

Postby Drumfix » Sun Feb 10, 2019 9:58 am

Ok, here is the pcm.c patch + a 3 quirks for proprietary 24, 32 and 64 channel mode.
Add the quirk that matches the number of channels you want to use. (this is why the file is not a patch file).
The number of channels must match the value you set in the "maxUSBToHost"

Note: the pcm patch is for my old 4.4.0 kernel.
You do not have the required permissions to view the files attached to this post.

ahellquist
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Re: Ultralite AVB

Postby ahellquist » Sun Feb 10, 2019 1:41 pm

Nice progress Drumfix

For those that have issues with bitcrushing, I settled on firmware 1.3.4+558 for my Ultralite AVBs and have no bitcrushing. The latest official build as the time of writing is 1.3.4+617 which is unusable for since it starts bitcrush immediately.

According to MOTU there were no changes between those builds that should affect usb sync/timing but I am not sure they are correct..

The 558 build was one of their betas but at least it has Touch Console UI and is stable for me.

There is a bug in Touch Console UI in all versions except the very latest one that took a long time for them to fix. I had to file three bug reports before it got fixed.. In Touch Console, the Low-Mid and High-Mid are mixed up. Not a show stopper but a little annoying.


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