This is a clean install of Zynthian on a Pi 4. The only change is to use a Behringer UMC202HD as the sound card, everything else is at defaults. I’m using a hdmi screen and USB keyboard/mouse
The sound card is recognised by ALSA. Ive configured it as a generic USB device in Webconf but copied the Jackd settings from the UMC404HD entry.
-P 70 -t 2000 -d alsa -d hw:U192k -r 48000 -p 256 -n 3 -s -S -X raw
RBPi audio is disabled.
The audio output is interrupted every half a second or so, so it sounds ‘chopped up’. The display doesnt show any XRun warnings
I’m assuming this is a USB buffer problem?
Thoughts or ideas on what to change ?
Malc
No idea what to change, perhaps
“aplay -l” will provide a clue. This is from a Zynthian V4:
“”“aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpihifiberry [snd_rpi_hifiberry_dacplus], device 0: HiFiBerry DAC+ HiFi pcm512x-hifi-0
Subdevices: 0/1
Subdevice #0: subdevice #0"”
You could also ‘aplay’ a file. I think this is what the ‘audio test’ function in Zynthian does.
What audio is playing?
You could also try -p 512 -n 2
44100 versus 48000 issues?
Has anybody come up with a solution for this? I am having the same problem with my UMC204HD. The chopping rate doubles when I change the sample rate in the audio config to 96000. I have tried various jackd settings. All audio coming out of the Zynthian does this including the audio test in the Admin menu. I had been using an AudioInjector which was working fine. Perhaps it’s an issue with the hardware? Are there other things I can do to try to diagnose this? Thanks for your help!
I have used my UMC202HD under zynthian a fair bit. I use a 404 as my daily driver though…
I know you will find this confusing, but can you tell us any more about the pi’s power supply and the lead you use to connect to it?
This is worth trying.
Yes, I tried this and it still had the same issue.
I am using an HP laptop usb-c power supply. It is supposed to deliver 5V/3A 15W. Is that not enough for this USB device?
Quite possibly, If it’s a laptop changer it will be trying to use negotiation with the pi to deliver the correct amount of power, certain early pi4 boards had a bug that meant this negotiation lead to the psu setting the lowest amount of power. Maybe try a different charger.
edit: ah, scratch that. the bug means no power, which isn’t what you’re seeing.
Apropos has anyone homebuilt a Type C power Supply that works with the Pi 5 ?
The idea of a chat between a power supply and a computer pretending to be a musical instrument brings out imagery somewhere between Douglas Adams and Dark Star. . .
Yes, I know pretending…
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Following up on this, I just tried the latest oram testing image and the audio worked fine on the UMC204HD with the default settings (-P 70 -t 2000 -d alsa -d hw:U192k -r 48000 -p 256 -n 3 -s -S). Still not sure what was causing the choppy audio on the stable image (and the earlier testing image I tried) but maybe someone who knows the system better can figure it out?
The main difference here is that it is now using 16-bit samples rather than 32-bit. This is a parameter that some soundcards require and I think the Behringers particularly benefit from it.
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Thanks, that makes sense. Shouldn’t I be able to specify that with the -S flag in the stable version? I still have the choppy audio in stable even when adding the -S (use shorts) flag to the jackd options. Is there another way to force 16-bit samples in the stable version?