I am in the early stages of learning DSP and am writing a simple synthesizer. I want to dabble in oversampling and am following this guide: https://www.nickwritesablog.com/introduction-to-oversampling-for-alias-reduction/
Adding 0’s and then doing an LPF is fine, but why would I then want to down-sample, as it states to do? When I play a sample back in response to a MIDI note, shouldn’t I just use the up-sampled buffer directly? Does playing a note count as the down-sampling part? If I were to up-sample, filter, down-sample, and then use that buffer to play MIDI notes, I would absolutely get the aliasing issue again, right? So I need to know that I am understanding this correctly and if not then I need a correction.