A creature must be able to hear the song to be affected by it. Silence means no sound can be created in or sent through it. If the spell couldn't stop magical sounds, the spell would say so. It is incorrectly implemented like many things are regarding silence, currently.

What is the problem you are solving? Does your proposed change solve the problem? Is your change feasible? What else will be affected by your change? Will your change impact revenue? Does your change align with the goals and strategies of the organizations (Larian, WotC)?