Hello experts!

I would like to run a cheap experiment. I will take a 10 or 12" subwoofer
speaker, and wish to make it pulse from 0 - 20 Hz. I would like to do this
relatively cheaply.

Needs:

1) Function generator - would be nice to have a digital display, but not
necessary. I see function generators all over eBay. It seems I can buy
anything that can produce my desired frequency range. (?)

2) Amplifier - I have NO idea what specifications I need here. I just wish
to make the speaker pulse at the low frequencies. I would like a good
pulse, a muddy vibration would not be good. What do I need to look for,
what should my spec. concerns be?

3) Subwoofer - I would like something relatively lightweight that I can
easily hold in my hand. I'm guessing that isn't an issue, as the cheaper
the speaker, the smaller the magnet, and the lighter it is.

4) Connectors - I see function generators tend to have BNC outputs. do I
look for BNC to RCA connectors at Radioshack? How should I connect the
generator to the amp?

Thanks for the advice,

John