Thanks for the information.

I'm processing this as I type, feel free to correct:

In theory you create a circuit to respond to a specific frequency range, let's say I want to focus on clean and clear, even, low bass ranges from 20 hz to 100 hz. Narrow for the purpose of how I am thinking through this, I would want a devoted route to pick-up, amplify, blend and balance. Now is that one channel for this example (monophonic) before being mixed and mastered? I then need to understand that current varies based on input volume and frequency, and a driver on the output end attempts to faithfully create wave patterns that match the input.

I know that drivers can respond to certain ranges. In my previous example I need a coil that creates the vibrations needed to reproduce the 20-100 hz range. The incoming signal has to be filtered and amplified in order to faithfully reproduce a very desirable sound.

All things equal, the frequency cutoffs were selected to maximize the ranges to allow an enjoyable product for the consumer, and make the recording and mastering engineer happy.

I have no clue if what I said makes sense, but I feel like it is a solid step one to grasping this theory from my perspective. If so, it makes sense to me as a musician. It would be like wanting to study how best to arrange your performers based on tone quality, blend and balanve during a musical phrase. Then adjust what is needed during the monitoring and eventual mastering phase.

No wonder rare radios/phonographs that could do this would be so expensive. It's akin to building the same equipment today.

Funny how this impacts the harmonic series of any given pitch.