I assume you could do create a single flashing rate with the editor in no time at all.

If you would rather though, you could overlay music with an audostrobe track. Audacity or any sound editor could overlay the tracks, and there is a lot of audiostobe software out there (bwgen, FutureMind, MindExplorer, neuro-programmer, or by just generating a 19.2kHz signal in any audio editor).