@samlo: thanks! Definitely look into upsampling, that's what makes the dood.al vectorscope so good, and it would be really nice if you find a way to make it auto-bind/register a loopback interface so it works without people setting up a virtual audio card just for this.
@juan: which emulator did you try? The one in then Windows package is quite bad, as I note in the Instructions on itch.io, but the one at https://dood.al/oscilloscope/ is really good, but requires a bit more set-up unless your sound card has 'stereo-mix' or you have a good audio setup already. Or check local ads/craigslist for a used analgo osci :stuck_out_tongue: