Miniamp + Pi Zero + Csound = distortion?

Hello all,

I've got a set of MiniAmps running on Raspberry Pi Zero WH boards, working towards a multichannel sound installation. I am consistently experiencing distortion with speakers rated for 3W or more, and I'm not sure what the issue is.

I have 5 Miniamps and 5 different Pi Zeros, and the performance is the same across all the units, so I don't think it's defective hardware. I am running a 2 channel csound score on each Pi, outputting a single sine wave with variable amplitude to each channel. I'm running csound at 44100 hz. I am using alsa.

Speakers I've tried:

CUI Devices CSS-66668N

CUI Devices GF1004

CUI Devices GF0668

The only time I've been able to avoid peaking is when I did one of these things:

1: turned the gain down so low in alsamixer that the sound was inaudible from more than a couple of feet from the speaker

2: plugged in a pair of passive Bose speakers, 8 ohm, rated for 10-120W. This sounds GREAT.

3: swapped out the miniamp for an Adafruit I2S Audio Bonnet and plugged in my headphones

I'm kinda at a loss. The only conclusions I can draw: either CUI makes garbage speakers and I should learn my lesson, or that I need speakers with a lot more headroom over the purported 3W output of each miniamp channel. Would love any ideas anyone has! I love the efficiency of the miniamp, and would love to be able to make it work.




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