I’m “almost there” with my retro set-up … Raspberry Pi 1 B+ and my brand new TASCAM US-16x08 .
The audio hardware is correctly detected by the OS as well as by Ardour . Ardour manages to start the audio engine, but immediately after that I get this, “Audio backend was shutdown because . ALSA I/O-Error .”
I knew this would be a no-go with the oldie Pi 1 B+, but I wanted to give it a try, possibly later going for a Pi 3, Banana Pi or ORDROID . Which one of these I wonder to go for ? Tell me ?
Just to rule things in or out, try another DAW - in fact, try another distro too - I make some RPi compatible plug-ins, I test using Ubuntu MATE 16.04 for RPi3, Tracktion Waveform for RPi3 (there’s a free demo version you can try), Reaper for Linux (RPi / ARM version) and Ardour. Swapping distros is relatively trivial - just burn them to different SD cards.
Ah good point - I only read RPi3 - Actually I wouldn’t expect the RPi 1 to be a usable DAW (I think I’ve said before, that while its fun to get this stuff to run on even the Pi3, and I make software for those with a use case which suits it, in many cases, by the time you have added the extra hardware required for conventional DAW tasks to the (incredibly cheap) RPi3 - you could probably pick up a used x86 desktop machine on ebay for about the same money and much better performance).
I have got Raspberry Pi Zero W which, I believe, is comparable to RPi1 B+. I can have Ardour working on it, even with 8 channel USB soundcard. Once you get it working you will discover that very little functionality of Ardour will be available to you, 3-4 tracks with EQ, maybe compressor on each at best. You should try another, leaner DAW - Qtractor - which is available from Raspbian repositories.
As for your problem: Try using JACK backend instead. Install Qjackctl and try to start JACK engine with TASCAM soundcard. I too have problems when I use 8 channel soundcard with ALSA backend : Ardour sends I/O error and complains about not being able to recognize channel count. When I connect my card via JACK, Ardour works just fine - and the situation is the same no matter if i use the card with RPi, laptop (Debian 9) or desktop (Debian 9).
If you use RPi1, full Raspbian may be too bloated system. I use raspbian-lite with only xorg, alsa, fluxbox wm and apps used for audio production, nothing else. Also make sure that you use SD card of sufficient read/write speed (U3, U6).
