As it turns out, high-end digital scopes with a 500MHz bandwidth are horrible for X-Y vector graphics, so I could not test anything meaningful.
The below should be the (untested) equivalent of your patch using
[soundfiler]: it should play the first
4410000 samples (that is 100 seconds).
However, I doubt it is a problem related to reading from file, really. That looks like noise in the outputs with a given periodicity. Do you have a sense from your what that periodicty would be ? Also, what is the maximum frequency in your signal? If that is just noise on the outputs, you could try getting rid of it with an analog low pass filter of some sort.
Can you describe your wiring and your amplification circuit?
I see that you are attenuating your signal a lot before outputting it. This means that:
- the DAC itself will have worse SNR performance than if it was operating almost full-scale
- the analog gain will need to amplify the signal more, thus amplifying any noise, or introducing new noise.
So I'd recommend you use an output level from Bela between 0 and 0.95 (that is 0V to 4.75V) and reduce the gain of the analog stage accordingly.
Before trying that, there is also another possibility: Bela has some DC-coupled line outputs for the audio outputs that are 1.8Vpp, centered around 1.3V. See here for more details. You could use those to replace two of your three analog outputs: these will be definitely quieter.