i want to buy a crossover that accepts speaker level right and left stereo inputs via banana plus (binding posts) and has a conversion to a LFE output (RCA plug) for a powered subwoofer. and i can change the crossover point. what can you tell me. it has been hard to find one of these. email@example.com
No body makes that for a good reason.
That's because the speaker output will overload the RCA inputs, or damage the amplifier, or both.
If you have a powered sub with RCA in, you can only connect line level to it. NOT speaker level.
You need a preamp / receiver / integrated amp with
preamp or subwoofer RCA outputs. That's it, sorry, no go.
Paradigm used to make just what you need but it has been discontinued for years. You can find a speaker to line level adaptor that will reduce the signal and match the impedance to drive any electronic crossover.