[sdiy] Additive/Subtractive synthesis?

[Ingo Debus]

Tim Ressel schrieb:
> Just caught this on my weekly backlog flush. The
> top-octave stuff I was doing is working, but I cannot
> verify the frequencies. The cheap-a$$ counter I have
> is not to be trusted.

You just need a reference frequency (digital synth). Feed that and 
your output signal into a two-channel scope and trigger with one of 
them. I use to tune my piano this way.
If you don't have a scope you can still add the signals and listen if 
they are beating (but opposed to the scope this won't tell you which 
frequency is higher if they are not same).

Ingo