Oddly enough, I measured the voltage when the speaker is making sound and it's roughly 3.2 volts analog signal. So, I tapped off a line from the speaker input, before it goes into the speaker, hooked up a 100uF cap in parallel to filter it. Pulled a reading off the high side of the cap into an analog input and it was stable around 300. Problem was when I made the tone in the speaker(via push button) there was no fluctuation of the signal. Reading stayed at 300.(with cap) Without cap, the reading was all over the place.
I then tried this full wave rectifier: http://www.radioshack.com/product/index.jsp?productId=2062581
Somehow the output voltage was 42 volts. I'm a little lost here.
It also seems that the warble tone line seems to be floating with some voltage on it even when there is no tone/signal coming through(button not pushed).
I'd like to try to condition that signal input to something more discrete. I'd still rather not use a mic. I have a piezo vibration sensor, but don't feel like trying to attach that to the speaker cone to read the vibes. The settle response time seemed very slow.
Thanks all for the replies so far.