Simple inline audio bass boost circuit ?

[Marcel Gonzalez]

I would like to take a line-level audio signal and boost the bass frequencies
before amplification. Any leads on a good circuit / kit ?

Marcel

 

[John Larkin]

I would like to take a line-level audio signal and boost the bass frequencies
before amplification. Any leads on a good circuit / kit ?

Marcel

Two resistors, one capacitor:



in-------r1------+-----------out
|
|
r2
|
|
c1
|
|
gnd


The values depend on where you'd like the break frequency and how much
boost you'd like. Try r1 = 1.2k, r2 = 270 ohms, c1 = 1 uF, and play
from there. Use pots for the resistors, maybe, for easier fiddling.

Picky: this will actually attenuate the highs, not boost the bass.
Same thing, if you just crank up the volume to compensate.

John

 

[John Woodgate]

I read in sci.electronics.design that John Larkin <jjlarkin@highlandSNIP
techTHISnologyPLEASE.com> wrote (in <650k00phnq0pb65ophl7vjvfgmfd3b8t34@
4ax.com>) about 'Simple inline audio bass boost circuit ?', on Sat, 17
Jan 2004:

Two resistors, one capacitor:



in-------r1------+-----------out
|
|
r2
|
|
c1
|
|
gnd


The values depend on where you'd like the break frequency and how much
boost you'd like. Try r1 = 1.2k, r2 = 270 ohms, c1 = 1 uF, and play
from there. Use pots for the resistors, maybe, for easier fiddling.

Those values are really too low. The source impedance, if this is
consumer or semi-pro equipment, can be 1 to 2 kohms. 10 kohms, 2.7 kohms
and 0.1 uF/100 nF might work better.

It gives 13.5 dB of boost at very low frequencies, which may be too
much. Increase the 270 ohm/2.7 kohm to get less boost.

Picky: this will actually attenuate the highs, not boost the bass.
Same thing, if you just crank up the volume to compensate.

That's all you can do, practically, with a passive circuit.

 

[N. Thornton]

I would like to take a line-level audio signal and boost the bass frequencies
before amplification. Any leads on a good circuit / kit ?

Marcel

Why before amplification? Its much easier to put a cap in the nfb path
to give you bass boost - dont forget an R across it for dc and to
limit the boost.

Regards, NT