Ultrasonic transmission for presence detection

1 . A receiving device comprising:

at least one processor; and

at least one non-transitory computer-readable medium comprising program instructions that are executable by the at least one processor such that the receiving device is configured to:

select a first nearby playback device detection technique from among a plurality of nearby playback device detection techniques, wherein the first nearby playback device detection technique utilizes a first signal type and wherein the plurality of nearby playback device detection techniques comprise (i) the first nearby playback device detection technique and (ii) a second nearby playback device detection technique that utilizes a second signal type;

while the first nearby playback device detection technique is selected, perform a first nearby playback device detection to detect a first playback device using the first nearby playback device detection technique, wherein the receiving device receives at least one first signal of the first signal type during the first nearby playback device detection; and

transition a playback session between the receiving device and the first playback device.

2 . The receiving device of claim 1 , wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the receiving device is configured to:

select the second nearby playback device detection technique from among the plurality of nearby playback device detection techniques;

while the second nearby playback device detection technique is selected, perform a second nearby playback device detection to detect a second playback device using the second nearby playback device detection technique, wherein the receiving device receives at least one second signal of the second signal type during the second nearby playback device detection; and

transition the playback session between the receiving device and the second playback device.

3 . The receiving device of claim 2 , wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the receiving device is configured to:

detect that an error occurred with an additional nearby playback device detection using the first nearby playback device detection technique, wherein the program instructions that are executable by the at least one processor such that the receiving device is configured to select the second nearby playback device detection technique comprise program instructions that are executable by the at least one processor such that the receiving device is configured to:

select the second nearby playback device detection technique when the error is detected.

4 . The receiving device of claim 1 , wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the receiving device is configured to:

select the second nearby playback device detection technique from among the plurality of nearby playback device detection techniques;

while the second nearby playback device detection technique is selected, perform a second nearby playback device detection to detect a second playback device using the second nearby playback device detection technique, wherein the receiving device receives at least one second signal of the second signal type during the second nearby playback device detection; and

transition an additional playback session between the receiving device and the second playback device.

5 . The receiving device of claim 1 , wherein the receiving device comprises a microphone, and wherein the program instructions that are executable by the at least one processor such that the receiving device is configured to perform the first nearby playback device detection comprise program instructions that are executable by the at least one processor such that the receiving device is configured to:

receive the at least one first signal via the microphone;

based on a time-frequency representation of the at least one first signal and data associating playback devices with respective reference audio signals, each reference audio signal having a predefined time-frequency representation, determine that the at least one first signal comprises a superposition of a first audio signal transmitted by the first playback device and at least one respective second audio signal transmitted by at least one additional playback device;

determine a first magnitude associated with the first audio signal is greater than second magnitudes associated with the at least one respective second audio signal; and

determine that the first playback device is arranged in closer proximity than the at least one additional playback device to the receiving device.

6 . The receiving device of claim 5 , wherein the second signal type is one of (a) Bluetooth or (b) an ultrawideband.

7 . The receiving device of claim 1 , wherein the program instructions that are executable by the at least one processor such that the receiving device is configured to transition the playback session between the receiving device and the first playback device comprise program instructions that are executable by the at least one processor such that the receiving device is configured to:

cause, via a network interface, transition of the playback session from the receiving device to the first playback device.

8 . The receiving device of claim 1 , wherein the program instructions that are executable by the at least one processor such that the receiving device is configured to transition the playback session between the receiving device and the first playback device comprise program instructions that are executable by the at least one processor such that the receiving device is configured to:

cause, via a network interface, transition of the playback session from the first playback device to the receiving device.

9 . At least one non-transitory computer-readable medium comprising program instructions that are executable by at least one processor such that a receiving device is configured to:

select a first nearby playback device detection technique from among a plurality of nearby playback device detection techniques, wherein the first nearby playback device detection technique utilizes a first signal type and wherein the plurality of nearby playback device detection techniques comprise (i) the first nearby playback device detection technique and (ii) a second nearby playback device detection technique that utilizes a second signal type;

while the first nearby playback device detection technique is selected, perform a first nearby playback device detection to detect a first playback device using the first nearby playback device detection technique, wherein the receiving device receives at least one first signal of the first signal type during the first nearby playback device detection; and

transition a playback session between the receiving device and the first playback device.

10 . The at least one non-transitory computer-readable medium of claim 9 , wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the receiving device is configured to:

select the second nearby playback device detection technique from among the plurality of nearby playback device detection techniques;

while the second nearby playback device detection technique is selected, perform a second nearby playback device detection to detect a second playback device using the second nearby playback device detection technique, wherein the receiving device receives at least one second signal of the second signal type during the second nearby playback device detection; and

transition the playback session between the receiving device and the second playback device.

11 . The at least one non-transitory computer-readable medium of claim 10 , wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the receiving device is configured to:

detect that an error occurred with an additional nearby playback device detection using the first nearby playback device detection technique, wherein the program instructions that are executable by the at least one processor such that the receiving device is configured to select the second nearby playback device detection technique comprise program instructions that are executable by the at least one processor such that the receiving device is configured to:

select the second nearby playback device detection technique when the error is detected.

12 . The at least one non-transitory computer-readable medium of claim 9 , wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the receiving device is configured to:

select the second nearby playback device detection technique from among the plurality of nearby playback device detection techniques;

while the second nearby playback device detection technique is selected, perform a second nearby playback device detection to detect a second playback device using the second nearby playback device detection technique, wherein the receiving device receives at least one second signal of the second signal type during the second nearby playback device detection; and

transition an additional playback session between the receiving device and the second playback device.

13 . The at least one non-transitory computer-readable medium of claim 9 , wherein the receiving device comprises a microphone, and wherein the program instructions that are executable by the at least one processor such that the receiving device is configured to perform the first nearby playback device detection comprise program instructions that are executable by the at least one processor such that the receiving device is configured to:

receive the at least one first signal via the microphone;

based on a time-frequency representation of the at least one first signal and data associating playback devices with respective reference audio signals, each reference audio signal having a predefined time-frequency representation, determine that the at least one first signal comprises a superposition of a first audio signal transmitted by the first playback device and at least one respective second audio signal transmitted by at least one additional playback device;

determine a first magnitude associated with the first audio signal is greater than second magnitudes associated with the at least one respective second audio signal; and

determine that the first playback device is arranged in closer proximity than the at least one additional playback device to the receiving device.

14 . The at least one non-transitory computer-readable medium of claim 13 , wherein the second signal type is one of (a) Bluetooth or (b) an ultrawideband.

15 . The at least one non-transitory computer-readable medium of claim 9 , wherein the program instructions that are executable by the at least one processor such that the receiving device is configured to transition the playback session between the receiving device and the first playback device comprise program instructions that are executable by the at least one processor such that the receiving device is configured to:

cause, via a network interface, transition of the playback session from the first playback device to the receiving device.

16 . A method to be performed by a receiving device, the method comprising:

selecting a first nearby playback device detection technique from among a plurality of nearby playback device detection techniques, wherein the first nearby playback device detection technique utilizes a first signal type and wherein the plurality of nearby playback device detection techniques comprise (i) the first nearby playback device detection technique and (ii) a second nearby playback device detection technique that utilizes a second signal type;

while the first nearby playback device detection technique is selected, performing a first nearby playback device detection to detect a first playback device using the first nearby playback device detection technique, wherein the receiving device receives at least one first signal of the first signal type during the first nearby playback device detection; and

transitioning a playback session between the receiving device and the first playback device.

17 . The method of claim 16 , further comprising:

selecting the second nearby playback device detection technique from among the plurality of nearby playback device detection techniques;

while the second nearby playback device detection technique is selected, performing a second nearby playback device detection to detect a second playback device using the second nearby playback device detection technique, wherein the receiving device receives at least one second signal of the second signal type during the second nearby playback device detection; and

transitioning the playback session between the receiving device and the second playback device.

18 . The method of claim 17 , further comprising:

detecting that an error occurred with an additional nearby playback device detection using the first nearby playback device detection technique, wherein selecting the second nearby playback device detection technique comprises:

selecting the second nearby playback device detection technique when the error is detected.

19 . The method of claim 16 , wherein the receiving device comprises a microphone, and wherein performing the first nearby playback device detection comprises:

receiving the at least one first signal via the microphone;

based on a time-frequency representation of the at least one first signal and data associating playback devices with respective reference audio signals, each reference audio signal having a predefined time-frequency representation, determining that the at least one first signal comprises a superposition of a first audio signal transmitted by the first playback device and at least one respective second audio signal transmitted by at least one additional playback device;

determining a first magnitude associated with the first audio signal is greater than second magnitudes associated with the at least one respective second audio signal; and

determining that the first playback device is arranged in closer proximity than the at least one additional playback device to the receiving device.

20 . The method of claim 19 , wherein the second signal type is one of (a) Bluetooth or (b) an ultrawideband.