but i want that sound! it has to be sample rate reduced. i don't want a clean nice signal.
i would not use the schematics on the intstructable site. have not even looked at it. i am able to do my own preamp and filtering at input stage, bias etc. i have built many pedals.
i just have never worked with arduino and this ADCH mode for the analog input.
so, back to my question. can you adjust the sample rate dynamically?
MarkT:
44kSPS is a reasonable sample rate for an audio processor. 1kSPS is most definitely not going to work except
on a bass synth output band limited to about 300Hz with a really good brick-wall filter, which is just
crazy.Do the decimation in software for low-pass filtering, a FIR low-pass followed by decimation can be
optimized to only apply the FIR once per output sample, not once per input sample.However you then need to oversample and low-pass filter again to reconstruct the output samples.
It may well be simpler to work at 44kSPS/38.5kSPS throughout.
The circuit given in that instructible is wrong BTW. No surprise of course.
ok, that is a start. but would that not mean that i can only get half the sample rate or a third etc? processing every n-th input sample only? i already tried this approach (just outputting every n-th sample) and it works, but control range is obviously very limited. or can you elaborate a little more? how would you decimate the sample rate smoothly? as i said lowpass filtering is not what i am after, since the signal should alias on lower sample rates... i also tried some software versions that use sample and hold to achieve kind of sample rate reduced sound, but it sounds not the same.