[DeTomaso] Muffler Options, active noise cancelling muffler

[Ken Green]

There is some confusion between exhaust flow and sound waves.  Your million watt stereo has zero net air flow but can make mondo noise.  I did a quick search on active noise cancelling automotive exhaust and got some hits, for example:
 
http://www.freepatentsonline.com/5325438.html
 
This is old technology, but maybe it's more feasible with technical developments?
 
Ken