FIR filter : how many taps do you need ?

With more taps, you get a better correction precision in lowest frequencies. But a too precise correction may be offsetted with varying parameters : temperature or humidity, opened/closed doors or windows, moved furniture, aso… So practically, 2048 taps is already fair and I don’t think that more than 16384 taps would really be usefull. And with most FIR processors, you can add some parametric EQ to finely ajust the lowest frequencies.