Hi. I've started to play with Tic-80 and one thing I've noticed as playing with the sfx is that from octave 1 to 3 appears to be a faint sound with higher frequency.
I tested on phone and on my pc. in both the program showed the faint high pitch. I've tested with all the default wave forms. After, I've tested with a youtube video (something like 25 to 100 hz) to make sure if the problem is not with my speakers.
Not sure if it is actually an issue or if it is just the way the dev wants.