[SOLVED] RME AIO

[MauryG5]

Hello InfiNeat, it is good to see that there are more and more users using this beautiful sound card on Linux. I wanted to understand one thing, how you use it with musical instruments, how you connect them and how you use the Hdspe AIO in this sense... Thanks

[khz]

A few years back I wasn't able to have my AiO work properly under Linux.
I'm glad I found this thread and didn't get rid of the AiO yet...
I just want to thank all who posted here and the developers.
Now it works perfectly. I'm very impressed, and happy

I am glad that the information is helpful. Have fun making music.

[WforWoollyMammoth]

In case somebody is looking for more information on how the RME HDSPe AIO card works on Linux, I should add the following:

Unfortunately, I've had some trouble with the MIDI input of this card. I get an xrun every 1-3 minutes when playing busier stuff on a MIDI keyboard that is connected to the MIDI in connector of the card. The xrun is audible with a crackling sound present that might be perceived intrusive when, say, rehearsing a piano piece. At first I thought it was just due to the software instruments being CPU heavy, or my own JACK settings, but it really seems to be the MIDI.

I've had the card inside two different systems (AMD Ryzen 7 2700 / MSI motherboard -based and an Intel Core i5 11600K / Asus motherboard -based one - running Ubuntu 18.10 with the Liquorix kernel and Ubuntu 21.04 with the stock low-latency kernel, respectively). The same problem occurs on both of them. I've also tried two different keyboards with old-fashioned 5-pin MIDI. I can't recall having had the same type of problems with my previous PCI/PCIe cards with MIDI connectors on them (although I think they might have all had the joystick port -type of connectors).

Using USB MIDI through the USB slots connected to the motherboard does not produce xruns in the same manner. If you're happy with USB MIDI, I can still recommend this card for anyone that's interested in it.

I should also add that I'm not sure if more channels than just two work when using ADAT, but isn't that pretty much the norm on Linux due to the lack of proprietary drivers in any case? The ADAT in / out can be switched to S/PDIF, if you prefer it that way.

[khz]

Sharing knowledge is more than desired.

With ADAT you can run all 8 inputs / 8 outputs simultaneously, this works 100%.
All extensions work 100% reliable, you can use all 18 inputs / 20 outputs at the same time.

With MIDI I have the same problem viewtopic.php?p=99715#p99715, which is strange IMHO.
I bought a hardware MIDI sequencer (Cirklon) which sends the stable/tight clock as well as MIDI commands via the 5-pin MIDI to the AIO $program(s) and/or to hardware instruments.
USB also works but I still think it's the worst solution because it has to be routed through all the layers https://en.wikipedia.org/wiki/USB_(Comm ... ocol_layer.
EDIT: USB is a block device - to go through umpteen layers, drivers and background services -, while MIDI sends every byte immediately - direct data paths https://en.wikipedia.org/wiki/MIDI#Tech ... ifications.
USB audio on the other hand is a stream.

[khz]

The best results are probably achieved with raw MIDI. https://www.alsa-project.org/alsa-doc/a ... wmidi.html With all its advantages and disadvantages.

[...] However, well known is as well, that jack-midi never was done for interact with "hardware synthesizers". For hardware midi handling you indeed better use raw alsa.
That changed, when interaction with software midi devices steps up in the game.
jack-midi is handled in the realtime-audio thread of jack. Developers needs to be aware that anything not real-time save shouldn't be done in the jack_process_callback, regardless if it is midi or audio. You may imagine that a couple of VSTi plugs ain't have a clue about this.

jack-midi does exactly what jeff proposed, no timestamp, plain messages handled as they comes in.
I must admit that I use midi only as a controlling interface, so jitter ain't matter for me, but, for my use case, jack-midi is the best, and painless choice for me and the users.
[...]

[WforWoollyMammoth]

Thank you khz,
I will do some more tests in the coming days / weeks, but I think I've already tested the MIDI on the AIO with all the ALSA and JACK MIDI options thoroughly. The recurring xrun (just a single one - but it's a loud "crack!" -type of a sound) takes place regularly no matter what the settings I've used have been. Maybe I've overlooked something and more tests are needed. Maybe I'll measure the intervals for the xruns too. I'd just need to redo the cabling in my system in order to do the tests again (not always the smallest of tasks )

It could be that the same problem concerns other PCI/PCIe cards with 5-pin MIDI connectors. I just don't think too many similar products that work on Linux are available anymore (Marian? Lynx? Does any of those PCIe cards actually work on Linux?). I used to have a M-Audio Delta 44 PCI card back in the day and I used it with a MPU-401 connector on the PC case without problems for years. I've also used a RME Babyface Pro with the MIDI being I/O'd via an MPU-401 connector on a secondary soundcard (a cheap old Terratec one - which I blacklisted as an audio card, but was still able to use the MIDI connector on it). The Babyface Pro functions just fine when using is own MIDI interface too (unfortunately, the Babyface Pro has all the latency issues associated with USB audio on Linux - and horrible h/w monitoring - and ultimately I just decided to get the AIO instead). The AIO card is the only product I've experienced this problem with, personally. Overlooking this issue, it's a great card, of course. I don't want to discourage anyone from buying it, because using USB MIDI is an option (you'd be using USB midi on all the USB audio interfaces out there and get the additional lags anyway).

The way the xrun occurs when using the AIO's 5-pin MIDI actually reminds me of two digital audio devices running nominally at the same sample rate, but that just haven't been synced properly. I don't know if the cause has anything to do with such a scenario, but it's almost like the system needs to "catch-up" at same point. Again, I could be totally off with that impression. However, I'm pretty certain that the CPU-heaviness of the software instrument, or what type of buffer/period -settings JACK runs at, have nothing to do with the issue.

[khz]

Further testing and possible fault isolations are very good. I have very little idea of the technical background of Linux & MIDI - have also already unsuccessfully tested quite a few possibilities - that's why I opened the 2 threads: RT MIDI >> viewtopic.php?p=99686#p99686, jackd - MIDI clock and MIDI 2.0 >> viewtopic.php?p=134113#p134113. Everyone is welcome to discuss there factually and possible ~missing functions. It would make me very happy.

[Philippe Bekaert]

Good news for those still looking for a hdpsconf for AIO (and AIO pro): I'm working on a new HDSPe card driver, named snd-hdspe, and user space configuration tool named hdspeconf. AIO, AIO Pro, RayDAT cards can be beta-tested already now. AES and MADI are to follow really soon.

https://github.com/PhilippeBekaert/snd-hdspe
https://github.com/PhilippeBekaert/hdspeconf

Enjoy,

Philippe.