I believe it's because you have the resonators in. They act like a "pre-muffler" to keep the tone down. removing these would then make your exhaust louder. You may want to keep them, however, in case you don't like the sound afterwards and can re-install them later.
a word for motionless or quiet is still.
still
Another word for quiet or motionless could be silent or still.
still
"Stillness" rhymes with darkness and means calm, quiet, or still.
1. (stative) be still, quiet, silent.http://www.maoridictionary.co.nz/
The comparative form of "quiet" is "quieter."
Being still.
slow
It is Still,
quiet, serene, calm, still, peaceable, undisturbed
Tell them to be quiet so the players can think and if they still won't be quiet ask them to leave.