H or X CROSSOVER?

I noticed drone was reduced when I went from separate duels to an X-pipe. Now, it didn't go away, it moved in RPM when it came on and went, about a 300 RPM shift and became about 20% quieter.

Mufflers alone will not stop or cure resonance, for that you need a properly sized resonator(s) and/or Helmholtz chambers.

2nd for Borla Pro XS for mufflers.