OK, so, I'm making a tone detector circuit with some analog components.

I began with using the LM386 and the LM567. After playing with the 386, I decided to build a condenser mic amp with a 741. It's working well as a single-supply circuit.

When thinking about the Gain I wanted, I stumbled on the bandpass filter equations. So I thought, "why not make the 741 mic amp a bandpass filter as well, to cut out environmental noise?" (I'm looking at capturing a 4kHz tone. Counting it too, but that's not part of my question)

Then I thought, "doesn't this make the LM567 redundant now?"

I'm still mulling it over. What say you good people?

P.S., I know that I could do this in many different and much easier ways. I'm doing this this way just because, and because I'm learning on-the-go. What I'm doing is roughly this:

Mic(amp) to LM567 to CD4022 to HT12E to RF module. My washer beeps three times at 4kHz when it's done, and I'm building a detector/notifier pair since it's in the basement and we forget about it all the time.