How do you measure the main frequency and dB of sound?

Hello

I want to analyze dB and major frequencies and give each desired effect in real time.
But I don’t know how to analyze dB and major frequencies.

I tried it like a picture, but this is not what I want.

What I want is a blue print that scales the major frequencies (like 500 to 800 Hz distribution) and dB in real time. After that, each one has a proper reverb effect.
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