Audio spectrum takes a huge amount of time to render as of late

I experienced the same issue with the audio spectrum effect today as well. A 4 minute song project that used to render in 5-10 minutes ended up taking 70 minutes on my M1 Max Mac Studio. I contacted Adobe support but no solutions so far. I had to send the files to someone who is using a Windows computer to help me render them.

Wiothout exact info about your system, your project, render settings and so on this is more or less meaningless. Could be a slow cache drive, could be issues with hardware acceleration, could be multiframe rendering, could be anything else. Either way, you have to be more specific.

Mylenium

If you are just adding an audio visualizer, there are a lot of web-based solutions that will do that in real-time. They have more options.

I don't know what has changed in your system or your project. If you updated After Effects, you could always use the Creative Cloud app to roll back a version or two.