Acoustic headrest with adjustable surface
Systems and methods of providing audio through or near a headrest are provided. A headrest includes an adjustable surface positioned to be proximate an occupants head when in use and an acoustic opening is configured to emit acoustic energy from an acoustic transducer in a range of directions in which an ear of the occupant is expected to occupy. The position of the adjustable surface gives some indication of the location of the occupants ear, and various audio signal (driver signal) properties may be adjusted based upon the position of the adjustable surface.
1 . A headrest comprising:
a substantially planar adjustable surface positioned to be proximate the back of an occupant's head when in use, the adjustable surface being linearly adjustable along at least one of a front-rear axis and an up-down axis relative to the headrest; and
an acoustic opening associated with the adjustable surface and mechanically coupled via an acoustic conduit to an acoustic transducer, the acoustic conduit configured to change length and/or shape in response to the linear adjustment of the adjustable surface; and
a processor configured to adjust a driver signal provided to the acoustic transducer based on a position of the adjustable surface, including compensating for changes in acoustic properties of the acoustic conduit caused by displacement of the adjustable surface.
2 . The headrest of claim 1 further comprising a sensor configured to detect the position of the adjustable surface.
3 . The headrest of claim 1 wherein the processor is configured to adjust the driver signal to compensate at least in part for a shadow region between the acoustic opening and the ear, the shadow region varying with the position of the adjustable surface.
4 . The headrest of claim 1 further comprising the acoustic transducer.
5 . The headrest of claim 1 , wherein the acoustic conduit comprises an accordion-style bellows or telescoping segment configured to elongate and compress in response to the planar surface's movement.
6 . The headrest of claim 1 , wherein the processor adjusts equalization, gain, phase, and/or timing parameters based on the detected displacement.
7 . The headset of claim 1 , wherein the processor adjusts phase and/or timing adjustments so as to maintain an inter-aural phase, inter-aural timing, and/or inter-aural gain.
8 . The headset of claim 1 , wherein the acoustic conduit is telescoping, flexible, or elastic.
9 . An audio system comprising:
a headrest having a substantially planar adjustable surface positioned to be proximate the back of an occupant's head when in use, the surface being linearly adjustable along at least one of a front-rear axis and an up-down axis; and
an acoustic opening associated with the adjustable surface and coupled to an acoustic transducer via an acoustic conduit that changes geometry responsive to displacement of the adjustable surface; and
a processor configured to adjust a driver signal provided to the acoustic transducer based on a position of the adjustable surface, including compensating for changes in acoustic properties of the acoustic conduit caused by displacement of the adjustable surface.
10 . The audio system of claim 9 further comprising a sensor configured to detect the position of the adjustable surface.
11 . The audio system of claim 9 , wherein the sensor detects both vertical and horizontal displacement and communicates the displacement to the processor.
12 . A method of controlling an audio output of an audio headrest having a substantially planar adjustable surface positioned to be proximate the back of an occupant's head when in use, the method comprising:
detecting a linear displacement of the adjustable surface along at least one axis; and
adjusting a driver signal provided to an acoustic transducer coupled to an acoustic opening associated with the adjustable surface via an acoustic conduit based on the detected position of the adjustable surface, including compensating for changes in acoustic properties of the acoustic conduit caused by displacement of the adjustable surface.
13 . The method of claim 12 , wherein adjusting the driver signal includes compensating for variation in the acoustic properties of the acoustic conduit caused by a change in length of the acoustic conduit.