I’m having an issue when using Zynthian on a Raspberry Pi 4 with the latest stable version of Oram. In my use case, when I use 2 patches per subsnapshot and play denser passages with many notes and the sustain pedal engaged, I get audio glitches (clicks/pops).
My setup consists of a Pi 4, a Maono USB audio interface, a Casio CDP-S150 keyboard, and an M-Vave SMK-37 Pro controller for patch switching (which takes around 1–2 seconds to change sounds). I am only using FluidSynth with SF2 soundfonts of approximately 250MB per patch.
I am using the system more as a sound module/rack for live performance rather than a full workstation. I would like to know if anyone has tested older, lighter versions of Zynthian (around 2022, such as stable-2211) in this kind of setup on the Pi 4, and if there is still any recommended way to access those images for comparison testing.
AFAIk, older images are not lighter. We really try to make new images lighter by reducing CPU usage and CPU waste as much as possible. We try to optimize the UI and have more CPU available for sound processing.
Most probably, the combination of engines that is producing glitches with Oram, was producing glitches in older versions too.
My advice;
Disable VNC is it’s enabled
Disable Mixer Peak Meters (admin menu)
Try to simplify your setup to avoid the glitches. You could use “htop” to see how CPU is being used.
If you are using big SFZ or GIG soundfonts, consider reducing the size or using a faster media storage.
A RPi4 should happily 2 FluidSynth chains wihtou glitches and changing sounds (via ZS3) should be near instantaneous. What you describe is not the behaviour I would expect.
The first point of concern would be the physical build. Is the RPi4 behaving well? Does it have sufficient cooling? Does it have a good PSU with high quality cable and connection? Are there any bad connections, e.g. on its 40 pin header? How are you presenting its display?
Next I would look at the audio interface. Low cost / quality audio interfaces can have substantial impact on the ability for zynthian to create sound. Some have such small audio buffers that the RPi is working very hard to service the audio stream. I am not familiar with the Maono devices (and you don’t specify which model you have) but they look towards the lower end of the market so it is plausible they suffer this issue. (I would not have assumed this as they are not dirt cheap but I would certainly investigate this.) If you have access to another soundcard, you could compare behaviour.
1-2 seconds to change sounds is odd but depends how what you are doing. I would expect a hardware controller to send a MIDI message within a few milliseconds of hitting a button. If this is a MIDI Program Change mapped to a ZS3 then I would expect Fluidsynth to have changed sound within 100ms (1/10 of a second). (These are wet-finger estimates chosen to be indicative of the kind of behaviour to expect.) You haven’t said how you are changing sound - maybe you are changing snapshot which will take a longer time.
As @jofemodo says, you should use the latest version of zynthian, either the current Oram stable or Vangelis testing (which is getting all the love at the moment) because these are likely to be more optimised, but even on older versions you should not be experiencing these issues.
