Is There A Device For Home Use That Can Measure How Low The Bass In My Speakers Is?

+1 to @djones51 ...dB on the SPL will tell you 'how much' vaguely, but a calibrated mic in even a eq like an 8024 Behringer will show you 'where' as well.

Used ones can be had for 100ish$ on average.

Buy a new mic, one never knows about the used ones.. Trips to the floor, the like...

Then you can play with it, if the mood strikes... ;)

Have fun, J