US Patent 10945058 Balanced stereo headphones with un-balanced air chambers

Speaker performance may be improved by increasing the effective acoustic chamber volume by fluidically connecting a speaker chamber containing a speaker with a mechanical housing. Additionally, the performance of left and right speakers may be balanced. Such balancing may be through equalization of the left and right speakers, balancing the acoustic impedance through sizing the openings between the speaker chambers and mechanical housings, and/or balancing of acoustic volumes within the speakers through use of ballast or acoustic expansion material to increase or decrease the effective acoustic volume of one of the speakers.