slejhamer wrote: My first bass teacher said I'd be better off learning to control my volume with my fingers and ears.
I agree with this, at least for home use. I am a huge proponent of people learning to get the tone and volume they want through good technique
before they start playing with gadgets and knobs. It is way better than re-learning your technique later if you realize you have a few tunes that only proper technique will help.
However, if you are playing a live gig (esp. if you are going straight into the house PA) or your slap technique constantly causes your amp to clip, I
would recommend a compressor of some kind. You don't want the sound guy to muffle the heck out of your signal because you are overdriving his system and you also don't want your sound to be too harsh on the audience.
I am a bit un-schooled on exactly how to dial in a fully-functional compressor (one with attack, threshold, decay, etc. parameters) so I generally use a Fishman active DI box with a dumbed-down compressor built-in (there are a few dumbed-down compressors on the market that consist of only one knob). You might start with something like that.