Thanks all!
I'm surprised that there isn't a good audio servo board out there. I see there is the scary terry kit, but that is about $50 after shipping. I' surprised nobody has released a simpler < $20 board. Thanks for the boris skull tip, I didn't know about them. I will keep my eyes peeled at the thrift stores.
Have you tried looking on Jammit?
Cool site, library is a bit weak but it looks to be growing. I'll keep my eyes on it.
I just wish I knew how exactly to extract voice myself as I want him to be my main Christmas/Halloween prop and sing appropriate songs without any false triggers.
Only accurate way is using phase cancellation, but you'll need the 'vocal' version of the track (ie. the music AND the vocal), plus the instrumental. When they're both played at the same time with the phase of one inverted, then the similar frequencies are cancelled out, giving you the accapella, which you can then record. It's still hit and miss for a load of reasons though. Otherwise, super-harsh EQ is your best choice, but far from perfect! Loads of stuff online about this, just google 'accapella extraction' or similar. Hope that helps, great project!
Thanks! I'll try this method.
Of course, I probably can just record myself singing along to the song and sync that with the music. I would have to make sure that channel only gets routed through Beaker and remains unheard. I have an awful voice, and it makes me cringe just listening to myself sing. I don't know what effects it would have on others.