Spatialized audio with dynamic head tracking
A device and method for providing spatialized audio with dynamic head tracking that includes, in a static phase, providing a spatialized acoustic signal to a user that is perceived as originating from a virtual soundstage at a first location, and, upon determining one or more predetermined conditions are satisfied, which can include whether the users head has exceeded an angular bound, rotating the virtual soundstage to track the movement of the user's head.
1 . A pair of headphones, comprising:
a sensor outputting a sensor signal representative of an orientation of a user's head; and
a controller, receiving the sensor signal, the controller programmed to output a spatialized audio signal, based on the sensor signal, to a pair of electroacoustic transducers for transduction into a spatialized acoustic signal,
wherein the spatialized acoustic signal is perceived by the user as originating from a virtual soundstage comprising at least one virtual source, each virtual source of the virtual soundstage being perceived as located at a respective position distinct from the location of the electroacoustic transducers and being referenced to an audio frame of the virtual soundstage, the audio frame being disposed a first location aligned with a reference axis of the user's head;
wherein the controller is further programmed to determine, from the sensor signal, whether a characteristic of the user's head satisfies at least one predetermined condition, the at least one predetermined condition including whether the orientation of the user's head is outside a predetermined angular bound,
wherein, upon determining the characteristic of the user's head does not satisfy the at least one predetermined condition, the controller is programmed to maintain the audio frame at the first location,
wherein, upon determining the characteristic of the user's head satisfies the at least one predetermined condition, the controller is programmed to rotate the location of the audio frame about an axis of rotation to reduce an angular offset with the reference axis of the user's head, wherein, while the user's head has a decreasing angular acceleration, the angular velocity of the rotation of the audio frame is selected such that audio frame will align with a predicted location of the reference axis of the user's head as the turn of the user's head comes to an end.
2 . The pair of headphones of claim 1 , wherein, while the user's head has an increasing angular acceleration, an angular velocity of the rotation of the audio frame is based, at least in part, on an angular velocity of the user's head.
3 . The pair of headphones of claim 1 , wherein the predicted location of the reference axis of the user's head as the turn of the user's head comes to an end is updated each sample that the user's head has a decreasing angular acceleration.
4 . The pair of headphones of claim 1 , wherein the at least one predetermined condition further includes whether an angular jerk of the user's head exceeds a predetermined threshold, wherein the at least one predetermined condition is satisfied if either the orientation of the user's head is outside the predetermined angular bound or the angular jerk of the user's head exceeds the predetermined threshold.
5 . The pair of headphones of claim 1 , wherein, upon determining the orientation of the user's head is outside the predetermined angular bound, the controller is programmed to rotate the angular bound about the axis of rotation in conjunction with the audio frame, wherein the location of the audio frame is rotated about an axis of rotation to reduce an angular offset with the reference axis of the user's head for a predetermined period of time after the orientation of the user's head is again within the angular bound.
6 . The pair of headphones of claim 1 , wherein upon determining the orientation of the user's head is outside the predetermined angular bound, a second angular bound, narrower than the angular bound, is rotated about the axis of rotation in conjunction with the audio frame, wherein the location of the audio frame is rotated about an axis of rotation to reduce an angular offset with the reference axis of the user's head for a predetermined period of time until the orientation of the user's head is within the second angular bound.
7 . The pair of headphones of claim 1 , wherein the at least one virtual source comprises a first virtual source and a second virtual source, the first virtual source being disposed in a first location and the second virtual source being disposed in a second location, wherein the first location and the second location are referenced to the audio frame.
8 . The pair of headphones of claim 1 , wherein maintaining the audio frame at a first location comprises rotating the audio frame at a rate tailored to eliminate drift of the sensor.
9 . The pair of headphones of claim 1 , wherein the sensor outputting the sensor signal comprises a plurality of sensors outputting a plurality of signals.
10 . A method for providing spatialized audio, comprising:
outputting a spatialized audio signal, based on a sensor signal representative of an orientation of a user's head, to a pair of electroacoustic transducers for transduction into a spatialized acoustic signal, wherein the spatialized acoustic signal is perceived by the user as originating from a virtual soundstage comprising at least one virtual source, each virtual source of the virtual soundstage being perceived as located at a respective position distinct from the location of the electroacoustic transducers and being referenced to an audio frame of the virtual soundstage, the audio frame being disposed a first location aligned with a reference axis of the user's head;
determining, from the sensor signal, whether a characteristic of the user's head satisfies at least one predetermined condition, the at least one predetermined condition including whether the orientation of the user's head is outside a predetermined angular bound, and
rotating, upon determining the characteristic of the user's head satisfies the at least one predetermined condition, the location of the audio frame about an axis of rotation to reduce an angular offset with the reference axis of the user's head, wherein, while the user's head has a decreasing angular acceleration, the angular velocity of the rotation of the audio frame is selected such that audio frame will align with a predicted location of the reference axis of the user's head as the turn of the user's head comes to an end.
11 . The method of claim 10 , wherein, while the user's head has an increasing angular acceleration, an angular velocity of the rotation of the audio frame is based, at least in part, on an angular velocity of the user's head.
12 . The method of claim 10 , wherein the predicted location of the reference axis of the user's head as the turn of the user's head comes to an end is updated each sample that the user's head has a decreasing angular acceleration.
13 . The method of claim 10 , wherein the at least one predetermined condition further includes whether an angular jerk of the user's head exceeds a predetermined threshold, wherein the at least one predetermined condition is satisfied if either the orientation of the user's head is outside the predetermined angular bound or the angular jerk of the user's head exceeds the predetermined threshold.
14 . The method of claim 10 , wherein, upon determining the orientation of the user's head is outside the predetermined angular bound, the angular bound is rotated about the axis of rotation in conjunction with the audio frame, wherein the location of the audio frame is rotated about an axis of rotation to reduce an angular offset with the reference axis of the user's head for a predetermined period of time after the orientation of the user's head is within the angular bound.
15 . The method of claim 10 , wherein, upon determining the orientation of the user's head is outside the predetermined angular bound, a second angular bound, narrower than the angular bound, is rotated about the axis of rotation in conjunction with the audio frame, wherein the location of the audio frame is rotated about an axis of rotation to reduce an angular offset with the reference axis of the user's head for a predetermined period of time until the orientation of the user's head is within the second angular bound.
16 . The method of claim 10 , wherein the at least one virtual source comprises a first virtual source and a second virtual source, the first virtual source being disposed in a first location and the second virtual source being disposed in a second location, wherein the first location and the second location are referenced to the audio frame.
17 . The method of claim 10 , wherein maintaining the audio frame at a first location comprises rotating the audio frame at a rate tailored to eliminate drift of the sensor.
18 . The method of claim 10 , wherein the sensor outputting the sensor signal comprises a plurality of sensors outputting a plurality of signals.