Audio Importer handles bringing music and audio files into Blender. On import, it bakes the audio into 10 frequency ranges and adds an All Frequency Node so you can see the frequencies. You get access to the individual frequencies through minimum and maximum sliders, and those frequencies are reachable from all node editors.
The add-on also brings the audio file into the video sequencer so you can hear the music, and it adjusts the end of the timeline to match the length of the sound file. It's part of the Music Video Toolkit from GhostVertex.
Distributed as a Blender add-on under the GPL license, Audio Importer is compatible with Blender 4.2 through 4.5, though support will stop after Blender 5.0. Documentation is included, and a demo video is available.