I have a noisy car. The engine is not a real issue, the wind noise increases quickly with speed, even at allowed highway speed.
I have some around-ear headphones with good sound insulation but I don't want to wear them as-is because I would lose awareness of the surroundings.
My guess is that I need to keep the sound in an audio band for speech, plus one for horns, and one for emergency sirens from ambulance and police. Wind noise is broadband and if these bands are well selected, it could be reduces significantly.
I thought about making a circuit with:
- electret capsule,
- multi-band equalizer to keep only the useful audio bands,
- audio mixer to sum the various audio bands with the line-level output of my car radio.
Everything powered by a regulated 9-11V supply from the car battery.
The electret circuit is easy and compact (for example Do electret condenser microphones require phantom power? ).
The signal mixer is also simple to implement (for example fig. 4 here).
The multi-band equalizer is not, since it requires a passband and opamp for each band.
With that in mind, how can I optimally reduce the number of audio bands with useful audio signals to maintain awareness while driving (in this case the mixer would have the n audio bands plus the external audio input), or what can I use to replace the discrete equalizer with some IC?
Maybe going digital is easier? however I only know Arduino and that one has a poor ADC and no DAC.