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RE: Questions about high pass filter and balanced bridge

Posted by JURB on June 14, 2017 at 00:12:25:
First of all when designing antrhing you make sure the output impedance is much lower than what the load will be draining. One notable exception might be loudspeakers.

In general, this approach means you won't have problems with the load affecting the output and that can matter when it comes to crossovers. If you have a 47K input impedance, then go for a 100 ohm output impedance. It also helps to keep the noise out.

The simplest way to really do it right is with some OP AMPS and RC filters. If you want variable crossover you can do it with one double ganged pot as long as you stick with 6 dB/octave. If you want 12 dB/octave then you need either a four gang pot or a separate control for each channel. Of course you can go with other electronic options but none of them are as sonically pure.

But basically, you feed it a voltage. Impedance matching is for RF or back when transistors only had an Hfe of like ten or so. today it is east to feed a constant voltage at very little cost. So pretty much forget about it and feed it voltage. That's what everything else does, except tubes...