US Patent 10412480 Wearable personal acoustic device having outloud and private operational modes

A method of operating an audio system that includes a wearable personal acoustic device having an acoustic driver and an auxiliary acoustic driver includes generating a first acoustic signal having a range of acoustic frequencies at the acoustic driver. A first change of operational mode of the wearable personal acoustic device is requested. In response to the request, a second acoustic signal having a first sub-range of the acoustic frequencies is generated at the acoustic driver and a third acoustic signal having a second sub-range of the acoustic frequencies is generated at the auxiliary acoustic driver. The first sub-range of the acoustic frequencies is different from the second sub-range of the acoustic frequencies and the range of acoustic frequencies is inclusive of the first and second sub-ranges of the acoustic frequencies.