Post by namke on Dec 3, 2020 17:03:17 GMT
(and if it is, how can I fix it?)
So today I decided to try and port the wonkystuff 'Core1' firmware to Grains (It actually turns out that there are some fundamental differences which will need some thinking about, but that's beside the point)
I was wondering why the output was sounding horrible, so I fired up my oscilloscope and found that the output is clipped horribly. Since my Braedboard module is next to the Grains, and the Grains output pin is easily accessible on the PCB, I quickly put together a simple reconstruction filter (10k resistor + 2 1nF capacitors in parallel)
…and compared the results:
The Grains output is noticeably clipped/overdriven.
This is more obvious when looking at a sawtooth output:
I have just built the reconstruction filter from the Core1 board, and the output is even smoother (which is nice!)
So, to my question - does anyone elses Grains behave like this? I hope that it is just mine that is faulty, and that I can repair it (of course).
For reference, I've added the sine-wave Grains code to my github here — also useful if anyone just wants a sinewave generator (slowscape ?!): minimism's GitHub
So today I decided to try and port the wonkystuff 'Core1' firmware to Grains (It actually turns out that there are some fundamental differences which will need some thinking about, but that's beside the point)
I was wondering why the output was sounding horrible, so I fired up my oscilloscope and found that the output is clipped horribly. Since my Braedboard module is next to the Grains, and the Grains output pin is easily accessible on the PCB, I quickly put together a simple reconstruction filter (10k resistor + 2 1nF capacitors in parallel)
…and compared the results:
The Grains output is noticeably clipped/overdriven.
This is more obvious when looking at a sawtooth output:
I have just built the reconstruction filter from the Core1 board, and the output is even smoother (which is nice!)
So, to my question - does anyone elses Grains behave like this? I hope that it is just mine that is faulty, and that I can repair it (of course).
For reference, I've added the sine-wave Grains code to my github here — also useful if anyone just wants a sinewave generator (slowscape ?!): minimism's GitHub
