Question about exhaust

[Boss75]

I've got a 99 Cobra with a MAC Prochamber and MAC Flowpath exhaust. I've noticed that when I'm around certain RPM's it gets louder and quieter. From about idle to 1800 its fairly quiet, then from 1800 to about 2200 its loud, and then its quiet again from about 2200 to 2800, loud again from 2800 to 3200 and etc. etc.

Does anyone else have this goin on? Can anyone tell me why my car does this?

 

[Iniquity]

From about idle to 1800 its fairly quiet, then from 1800 to about 2200 its loud

It's called a Drone. and I doubt your exhaust goes quiet.

 

[Boss75]

Hehe. Actually just above 2200 its almost silent.

 

[RED92VERT]

All exhaust systems will have diff sounds at diff RPMs. My magnaflows are quiet until i hit 3k and then they scream.