Adding microphone to line input

[stuee]

Ok so ive now got a 400w amp, it is designed for full frequencies with treble and bass and l/r line in but it outputs to 1 speaker.

My question now is...
can i add a variable cutoff filter so i can select the bass frequency it uses and just split the line out from the mixer to the amp. i still want both the normal to produce all frequencies including the bass but the sub for bass only.
is this possible and could you design a simple circuit for me AG so i can go get the parts and make one.

thanks

 

[audioguru]

I looked in Google for Variable Lowpass Filter For Sub-woofer Amplifier and found hundreds of them. I copied this one and changed the inputs and output so it will do what you want:
https://www.redcircuits.com/Page142.htm

 

[stuee]

Would one of these suit my needs?
https://www.wagneronline.com.au/subwoofer-crossover/filters/9-909xx1-product~tags/ps/

 

[stuee]

or this
https://www.altronics.com.au/p/k5562-subwoofer-controller-short-form-kit/

 

[audioguru]

G'day again Stuee.
I remember you from a few years ago in down under, mate.

One of the Wagner crossover products will feed your sub-woofer amplifier perfectly.

 

[stuee]

Hahaha AG, Yes mate, you have helped me a few times over the years with your expertise.
So the Wagner ones. which one would suit best as there is 4 different ones.
cheers mate

 

[stuee]

My bad, i dont know why they have the same item listed 5 times!

 

[audioguru]

Hahaha AG, Yes mate, you have helped me a few times over the years with your expertise.
So the Wagner ones. which one would suit best as there is 4 different ones.
cheers mate

My bad, i dont know why they have the same item listed 5 times!

The one crossover product is stereo so simply use one channel in and out to one channel of your subwoofer amplifier.
Use a 10k resistor from your music source Left channel and another 10k resistor from your music source Right channel and connect the other ends of the resistors together to make mono to feed the input channel of the Wagner crossover that you are using.

 

[stuee]

The amp i have on the sub now is actually l/r input and outputs to 1 speaker so i will just run l/r into the xover and l/r out
thanks

 

[audioguru]

Does the sub-woofer amplifier mix left and right channels together which is what you need?