This assemblage is advised to be affiliated to an absolute car stereo amplifier, abacus the generally appropriate added "punch" to the music by active a subwoofer. As actual low frequencies are omnidirectional, a distinct amplifier is all-important to drive this committed loudspeaker.
The ability amplifier acclimated is a acceptable and bargain BTL (Bridge Tied Load) 13 pin IC fabricated by Philips (now NXP Semiconductors) acute a actual low genitalia calculation and able of carrying about 22W into a 4 Ohm amount at the accepted car array voltage of 14.4V.
The stereo signals advancing from the band outputs of the car radio amplifier are alloyed at the ascribe and, afterwards the Akin Control, the arresting enters the absorber IC1A and can be appearance antipodal by agency of SW1. This ascendancy can be advantageous to acquiesce the subwoofer to be in appearance with the loudspeakers of the absolute car radio.
Then, a 12dB/octave capricious abundance Low Canyon clarify congenital about IC1B, Q1 and accompanying apparatus follows, acceptance to acclimatize absolutely the low canyon abundance from 70 to 150Hz. Q2, R17 and C9 anatomy a simple dc voltage balance for the ascribe and clarify circuitry, advantageous to abstain absolute abuse alternation from the ability amplifier to low akin sections.
Notes:
- IC2 must be mounted on a suitable finned heatsink
- Due to the long time constant set by R17 and C9 in the dc voltage stabilizer, the whole amplifier will become fully operative about 15 - 30 sec. after switch-on.