FFT (or similar) library for the Arduino
I havent used any of the libraries to make the FFT for my personal project, due to complexity. Instead I bought a spectrum chip, which returns 7 frequencies: MSGEQ7  ( 63Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6.25kHz and
16kHz ).

Otherwise if you are very keen on using a library, this one is very famous and fast for Arduino processors.

But again, if you dont need to have a precise band and the MSGEQ7 is good enough to detect what you want, go for it.