What's a good freq too filter off the bass from, to retain as much of the sound as possible whilst still making it listenable? Think I read elsewhere on the board around 300Hz to eliminate.
Two factors will impact your HPF (high pass filter, or bass roll-off): frequency and slope. The frequency represents the point at which one one starts to apply the filter; the filter is applied to frequencies below this point. The slope is how quickly one wishes to filter below the frequency target, i.e. how swiftly to roll off the bass, typically noted in dB / octave. Common values are -12 dB and -6 dB, but that doesn't mean you have to use those specific values. (-12 dB / octave will remove bass more quickly as you move below the frequency target, while -6 dB / octave will remove bass more slowly.)
300 Hz sounds awfully to high to me, but the actual value will depend on your recording, ears, playback, etc. Try starting at 80 Hz with a -6 dB /octave slope. I'd then try 80 Hz with a -12 dB slope. See how it sounds. If it doesn't remove enough low end, move the frequency up (to say, 100 Hz) and try both -6 and -12 dB slopes again. Or if it removes too much low end, drop the frequency to, say, 60 Hz. Experiment until you find a frequency and slope appealing to your ears.