I made a decent audio visualizer using the MSGEQ7 [1]. It buckets a count for seven audio frequency ranges—an Arduino would poll on every loop. It looks like the MSGEQ7 is not a standard part any longer unfortunately.

(And it looks like the 7 frequencies are not distributed linearly—perhaps closer to the mel scale.)

I tried using one of the FFT libraries on the Arduino directly but had no luck. The MSGEQ7 chip is nice.

[1] https://cdn.sparkfun.com/assets/d/4/6/0/c/MSGEQ7.pdf

Have you ever seen anything like a MSGEQ14 or equivalent? It would be cool to go beyond 7 in such a simple-to-use chip, but I haven't seen one.