Our microphones have a very flat and extended low frequency response.
In some cases, particularly where the hall has an emphasized bass
frequency response ("hall boom"), you are recording near a room
boundary, the air conditioning system rumbles, traffic noise filters in
from outside, or the room's sound system is equalized strongly toward
the bass, it is desirable to roll off the low bass frequency
To address this we offer two battery boxes with bass roll-off filters.
One has a fixed-response bass roll-off filter. The other offers a
The switchable box has a very high quality, locking mini-toggle switch
mounted on the outside of the box under the mini-XLR jack. It is
switched between flat response and the bass filter response very easily,
but the locking toggle lever must be pulled outward to switch filter
positions, and so can't be accidentally switched.
When used with recorders like the Sony PCM-M1 and TCD-D8, the bass
roll-off filter rolls off frequencies below 120 Hertz at 6 dB/octave.
In general, we don't recommend that you have only the bass roll-off
filter unless you regularly note too much bass in your recordings. If
you want to be able to select between a flat and a rolled-off response,
we recommend having the switchable box, or two fixed-response battery
boxes on hand: one that's flat and one that has the roll-off filter.