US Patent 8989427 Earphones

An earphone includes a first acoustic chamber with one or more of a reactive element and a resistive element for acoustically coupling the first acoustic chamber with an environment external to the earphone. The earphone includes an acoustic transducer and a second acoustic chamber separated from the first acoustic chamber by the acoustic transducer. A housing supports the earphone from the concha of a wearer's ear and extends the second acoustic chamber at least to an entrance of an ear canal of the wearer's ear. A port acoustically couples the first and second acoustic chambers.