Low pass filter

[BernieH]

I am thinking about changing a pair of speakers by eliminating bi-amp and adding a low pass filter looking for thoughts:

Have a pair of tower speakers (carver) which were originally designed to have freq input above 100 hz ( 4 ohm)to the first set of binding post and freq 100 and below (4 ohm) to the second set (crossed over before the input) The towers have a tweeter, a rear firing mid, and a front firing mid in the top portion then a 10” sub firing from the side / front facing port.

the crossover for the top portion is in place but is expecting material above 100 hz. Wanted to tap into this top section adding a low pass filter and eliminate the use of the lower binding post. The original specs call out a 12db slope so thinking a 2nd order Butterworth? Thoughts?

the system was originally designed for surround sound but that would not be my use. I suppose I could use a sub amps speaker level inputs, use its low pass ability, then create an external high pass filter somewhere early in the path for the top section. If I did this my kg-5230 would not handle a 2 ohm load so the left and right 10” drivers would need to be wired in series... seems cleaner just to add the low pass in each box but not sure what I would be sacrificing

appreciate comments

 

[TudorTurtle]

If these are the 5.2s, won't you still need a subwoofer amp for the side woofers?

But yeah, a cap in line and a coil to ground for the top sections should work...if it's really needed. Meaning; do the mids misbehave below 100 hz, or is their natural rolloff OK.

 

[BernieH]

Thanks!

they Are the left and right from 5.2

As for the rolloff I really don’t know I need to remove that and see what kind of driver it is I thought I heard these could be peerless driver maybe I can match the model. I don’t have the ability to test it otherwise. The CS 5.2 manual does warn that there could be damage if the full range frequency is used but that could be referring to the sub portion.

As for the subwoofers that is the primary question. What I thought I would combine the 10” so no separate powered sub but added as a low end driver...basically making this a 4-way system.
The other option is to use my kg-5230 and keep the subs separate...now that I think about it the 5.2 specs call the sub out as 4 ohm but they may be 8 ohm and the CS 5.2 subwoofer amp may have been wired so these would be connected in parallel making the sub system as a whole 4 ohm I suppose this could be possible? Which really would make my sub amp a direct replacement. I’ll remove one of them...I can test the resistance.

b

 

[TudorTurtle]

You don't have to remove the driver, just use the terminals, there shouldn't be any crossover filter on the woofer section. It got power and filter from the sub-amp.

 

[BernieH]

Okay here is what I have found and my plans

Without question the tower is expecting input for the top section to be above 100hz only and input for the bottom (sub portion) 100hz and below. The spec indicate both top and bottom are 4ohm and 12db crossover slope. When I meter these from the binding post they are both 3.5 ohm.

my plan as it stands is to create an external 2nd order butterworth — a high pass and low pass each at 100hz. From there the high/low pass signal will be patched into their respective locations. The top does have additional crossover circuitry for the tweeter and mids. If I calculate the components for the external 2nd order I get 282uf capacitor and 9mH inductor...this would be x 2? One set for high pass same set for low pass and switching series / parallel (high pass) and parallel/ series (low pass). So my questions:

1) this should work yes?
2) should I be looking at a different way?
3) since both top and bottom are metering at 3.5 ohm and not 4, am I better to use the 3.5 in calculating the required capacitance / inductance or hang with the 4ohm called out by the Carver specs?

thanks for the thoughts