RNBO on Raspberry Pi 400?

Jean-Francois Charles's icon

Hi,
Has anybody used RNBO on a rPi400? With which sound card? PiSound or class-compliant USB?
Thanks for sharing your experience!

Jan M's icon

Hello Jean-Francois,


I am using RNBO with a Raspberry Pi 4(not 400) building a standalone analog modelling synth. I wouldn't expect those two to behave different with RNBO. Currently I am using a ZOOM U-24 that I had lying around. No problems regarding the sound so far except a little noise (probably a ground loop). A ground-lift DI box solved that.

Sometimes the MIDI In port of that card does not seem to be recognise, so I switched to a cheap USB-MIDI interface. Works flawless so far.
I ordered also a PiSound. It should arrive in a few days. As soon as I have it I can share my experiences.

I find the results of RNBO on a Pi pretty impressive. And also the workflow is very elegant. Before I tried to use a the Witch from Rebel technology, but the workflow is not really a flow, the device underpowered and some more caveats so I gave up on that one. The RNBO/Pi combination is quite a different beast. I really love it!

Jean-Francois Charles's icon

Great, thanks for sharing that. If someone has tried with rPi400, I'm still curious to know the results. I hope to have some time in a couple of weeks to try it myself, will let you know, of course.

Jan M's icon

Bonsoir Jean-Francois,

My PiSound arrived today and I made my first quick test.

The setup is straight forward. To install the drivers/software it is a one-liner on the command prompt. The guide is on their website. It worked out of the box. The Pi needs internet connection for that though.

Sound Quality seems very good, no hums, noises or anything like that. And it performs much better than the USB sound interfaces that I tried before. I am running a patch that emulates an analog synth with 6 voices. With the USB interfaces I had to set the vector size (period_frames) to 128 samples when num_periods was set to 1. I assume that one corresponds what is called I/O Vector Size and the other Signal Vector Size in Max. Though I am sure sure which one is which. Depending on what preset I was playing I had to set it up to 256 to be sure to have no click. The PiSound easily handles a period_frames setting of 64. My Pi is overclocked to 2.3 GHz following this guide: https://beebom.com/how-overclock-raspberry-pi-4/

A noticeable impact in the tuning made to use the PiSetting force_turbo=1.

This seems to prevent the Pi from slowing down the clock speed when voices are muted. Without that, when the clock ramps up, because more voices are activated that could cause clicks as changing the clock speed seems to be rather slow on the Pi. To have an analog amplifier on the output and and analog gain stage on the input is a really nice feature. That allows me to run signal levels in my patch on a safe level and amplify the sound outside the patch. The gain pot hat a center detent at 0 dB. Nice detail :)

So first impressions summary: Thumbs Up!

Jan M's icon

I have one more addendum: The PiSound Software comes with a preconfigured WIFI hotspot option. Meaning, being out in the field, exhibition or stage and I want to change parameters via the browser interface, the Pi creates its own network for that. Man, my smile is getting wider :)))

Jean-Francois Charles's icon

Thanks for the update! Smiles indeed!

Jean-Francois Charles's icon

Hi there, I just want to confirm that yes, rnbo works fine on Raspberry Pi 400. I've tested with a UCA222 audio interface, no problem.