Thanks for the detailed report, you were spot on! Hitting "max" on Compound Capital was buying each point one at a time, and every single purchase fired its own sound, so with thousands of investors they all piled up into that delayed, overlapping noise.
Fixed in v0.6.1, which is live now: "max" places all your points in one go with a single sound, and the game now caps how many sound effects can play at once, so fast tapping or the auto-manager can't stack them up either. Let me know if you still hear anything odd!