Bass roll-off is useless for folks taping line-in and only for people
who record mic-in.
The bass roll-off is not disabled when going line input. The analog
bass roll-off feature of the passive SP battery box will work into
*any* downstream device (line or mic-in) BUT the frequencies stated
(the -3dB knee of the filter) will be valid for one input resistance
only! The one specified is that of a generic mic input (10 kOhms?).
When going line-in (47 kOhms on many Sony consumer units) the filter
knees are shiftet drastically downward in frequency. A "100 Hz" high
pass suddenly passes everything above 20 Hz (5 times less)... I.e.
barely any bass roll-off at all.
Mic-in frequencies :
16Hz (no roll-off) 2,3,4
69Hz 1,4
95Hz 1,3
107Hz 1,3,4
160Hz 1,2
195Hz 1,2,4
888Hz 1,2,3
Line-in frequencies (5 times less) :
(16Hz) > 3,2Hz 2,3,4
(69Hz) > 13,8Hz 1,4
(95Hz) > 19Hz 1,3
(107Hz) > 21,4Hz 1,3,4
(160Hz) > 32Hz 1,2
(195Hz) > 39Hz 1,2,4
(888Hz) > 177,6Hz 1,2,3
So... the only "valid" roll-off frequency when recording loud concerts
at boomy venues using line-in will be 888Hz.
OBS: If you have the SP battery box with output level control the
frequency will depend on the setting of the level.
