Recording line-in makes the bass roll-off filter inoperative

[fandelive]

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.

[redwingnut26882]

I record line in with a bass rolloff. My minidisc is less sensitive to heavy bass than my DAT. I usually use 195hz for the MD, and 888hz for the DAT, for small clubs. I am wondering what affect a -20db attenuator cable would have on the numbers?