Headset Porting

An around-the-ear headset cup comprising:

• a front cavity;
• a rear cavity;
• a driver disposed between the front cavity and the rear cavity, the driver configured to radiate sound pressure levels larger than 120 dB;
• and
• a first port connected to the rear cavity, the first port being configured such that a resistive component of an acoustic impedance of the first port is larger than a reactive component of the acoustic impedance of the first port;
• and
• a second port connected to the rear cavity such that an acoustic impedance of the second port is parallel to the acoustic impedance of the first port, the second port being configured such that, at frequencies less than 100 Hz, a reactive component of the acoustic impedance of the second port is larger than a resistive component of the acoustic impedance of the second port.

A headset comprising,

• at least one around-the-ear cup having a front cavity and rear cavity;
• a driver configured to radiate sound pressure levels larger than 120 dB, the driver disposed between said front and rear cavities,
• wherein the ear cup comprises:
• a first port connected to the rear cavity, the first port being configured such that a resistive component of an acoustic impedance of the first port is larger than a reactive component of the acoustic impedance of the first port, and
• a second port comprising a tube having an inside surface that is substantially smooth, the second port connected to the rear cavity such that an acoustic impedance of the second port is parallel to the acoustic impedance of the first port, the second port being configured such that, at frequencies less than 100 Hz, a reactive component of the acoustic impedance of the second port is larger than a resistive component of the acoustic impedance of the second port;
• and
• an active noise reduction system coupled to the driver.

An apparatus comprising:

• a first around-the-ear cup shell of a headphone;
• a second around-the-ear cup shell of the headphone;
• an electroacoustic driver configured to radiate sound pressure levels larger than 120 dB, the electroacoustic driver disposed between the first and second around-the-ear cup shells, such that the first around-the-ear cup shell and a first face of the driver define a front cavity, and the second around-the-ear cup shell and a second face of the driver define a rear cavity;
• a metal tube having an internal bore with substantially uniform cross section, the metal tube seated in the second ear cup shell and coupling the rear cavity to space around the apparatus, the metal tube configured such that, at frequencies less than 100 Hz, a reactive component of the acoustic impedance of the metal tube is larger than a resistive component of the acoustic impedance of the metal tube
• wherein the second around-the-ear cup shell comprises plastic, and the metal tube comprises a rough exterior surface at one end, the rough exterior surface being anchored in the plastic of the second around-the-ear cup shell.