While I'm thinking about it. I had a thought awhile back that the tone generator is quite useful, but one thing that I wish it would do is output 2 or 3 sine wave tones at once. It'd be great for speaker testing if you could pick output something like a 10hz tone with a 105hz tone at the same time and listen for modulation issues. That or doing 1/3rd octave spaced distortion tests. There'd be a lot of possibilities if you could independently select even just 2 different freq's.
I didn't know how difficult this would be to implement. It's a suggestion.
Multitone signal generation Is not difficult, but of course to make it useful it would really need the RTA to measure the levels of the intermod products and calculate the intermod distortion. All on the list, but its a long list