Active crossover conversion

I currently have a setup consiting on an amp driving a stereo subwoofer (it has 8 small drivers in total). In that sub there is a 2nd order high/lowpass pair with cutoff frequencies of 100Hz. The high pass of this then feeds into a pair of stereo bookshelf speakers, which are 2 way and have a crossover of some description inside.

Now to me this sounds fine but Imagine with the string of crossovers it could be greatly improved. My plan was to start by building an active 2nd order low/high to replace the passive in the sub, and then if I can find another stereo amp (I only have 2 at the moment) I would go 3 way active later on.

My question is, if I build a 100Hz low/high pass filter, can I use the high pass output later on to drive another ~3khz high/low pair? Or would it be better to take all of the inputs from the same source and then make seperate low/high/mid pass filters?
Active filters usually use the pre-amp output stage from your source, then pass the filtered signals to the separate power amps to drive the speakers.

It sounds like you're planning to run the speaker wires from your sub to the second active filter when you're ready to add that to your system. I suppose it could work if you can rig your second filter to accept speaker level inputs, but I just don't see a good reason to do this. What seems more practical is to add your second filter to the first, so it becomes an integrated 3-way, rather than a 2-way going to another 2-way at speaker level, which is essentially what you'd be doing.
I think i may have explained it badly, I've attatched a picture of my idea. Its either do this or do 3 seperate filters being driven from the preamp, a lowpass/bandpass/highpass to drive the seperate speakers. The configuration in the picture is my preference as it will allow me to make just the 100Khz high and lowpass filters first.

Just to point out all of the filters will be located in one box and then rigged to 3 stereo amps by phono leads, and then these amps will be connected to the speakers with short cable.


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