I tried it by using the microphone input looped to an audio device monitor and playing the downloadable (wav) for scope-quake. The scope locked up and would not respond until I reloaded the page. Maybe it works for you? Give it a try.
There's a lot of attention to detail here! I used to have a clunky analog oscilloscope and I see some subtle but important behaviors in the model like the bloom when the intensity is turned up. It seems that to control the knobs I'm supposed to click and drag up and down instead of side to side. Couldn't figure out how to get the FFT to show up, but everything else looks good.
Something's off with trigger, setting it to channel A when both channels generators run at different frequency should make the second channel waveform "float" as it is unsynchronized. Normally those 2 channel scopes have per-channel trigger source
why is this so stationary? I had worked with real oscilloscopes, and it's always tricky to get a steady picture, especially on the old analog ones. But here, no matter what I do, the picture is rock solid.
Two slightly detuned generators added up? Somehow beat frequency does not appear.
Mess with trigger? Real scope would either switch to "auto" mode with wildly changing signal or have picture disappear entirely. Here, it's basically no effect.
CH1 mic worked for me, but only after I also turned on CH2 mic. CH1 mic turns off if CH2 mic turns off.
But you can see both channels work (if both are on mic) by sliding the position of one of the channels. Not certain if it's actually using stereo input on my mac, but they are different. I couldn't do anything to deliberately make one louder than the other.