Internal ported band pass enclosure for sound cancellation

A sound cancellation system for sound pressure waves propagating through a conduit comprising:

• a detector transducer for sensing the sound pressure waves and generating a control signal in response to the sound pressure waves detected;
• control means for generating a drive signal in response to said control signal;
• a transducer coupled to receive said control signal;
• said transducer being mounted in an enclosure defining a chamber, said chamber having a partition separating a first portion of said chamber from a second portion of said chamber, wherein said transducer has a diaphragm with a first side facing said first chamber portion, and with a second side facing said second subchamber;
• a first port coupling said first chamber portion to said second chamber portion, and a second port coupling one of said first and second chamber portions to the conduit.

A muffler system for a motor vehicle exhaust conduit, comprising:

• a detector transducer for generating a control signal in response to sound pressure waves propagating through the conduit;
• an electronic control for generating a drive signal in response to said control signal;
• a transducer for generating a cancellation signal in response to said drive signal;
• wherein at least one of said transducers is mounted in an enclosure defining a chamber, said enclosure including a partition and forming a first chamber portion communicating with one side of the transducer's diaphragm and a second chamber portion communicating with a second side of the transducers diaphragm, a first port communicating between said first chamber portion and said second chamber portion, a second port coupling one of said first and second chamber portions to said conduit.