see https://rabid.prototyping.xyz/procedural-mesh-generation-from-live-audio-in-unreal-engine-4/ for a short description
https://github.com/SiggiG/ProceduralMeshes and https://forums.unrealengine.com/showthread.php?94974-eXi-s-Sound-Visualization-Plugin-(works-in-cooked-builds)-4-13-Version/
Everything written by me is MIT. For others go see their respective licenses. (eXi's sound viz is MIT, SiggiG's procedural mesh project is MIT as well, KissFFT is DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE)