A headset apparatus including a speaker housing having an acoustic impedance and configured for conversion between a first listening mode and a second listening mode by rotation of the at least one speaker housing about an axle. The headset apparatus includes at least one vent configured to alter the acoustic impedance of the at least one speaker housing. The headset apparatus also includes a valve configured to open the at least one vent in the first listening mode and configured to close at least some portion of the at least one vent in the second listening mode.Published versio