1. An audio system comprising: multiple loudspeaker devices, each loudspeaker device comprising: a loudspeaker; multiple microphones, each microphone producing an input audio signal representing received sound; and one or more processors; a first loudspeaker device comprising one or more first computer-readable media storing computer-executable instructions that, when executed by one or more processors of the first loudspeaker device, cause the one or more processors of the first loudspeaker device to perform first actions comprising: receiving a first set of input audio signals produced by first microphones of the first loudspeaker device, each of the first set of input audio signals representing first sound; determining that the first sound corresponds to a command spoken by a user; analyzing the first set of input audio signals to determine a first relative position of the first loudspeaker device relative to the user; and producing second sound using the loudspeaker of the first loudspeaker device, the second sound comprising speech that acknowledges the command; a second loudspeaker device comprising one or more second computer-readable media storing computer-executable instructions that, when executed by one or more processors of the second loudspeaker device, cause the one or more processors of the second loudspeaker device to perform second actions comprising: receiving a second set of input audio signals produced by second microphones of the second loudspeaker device, each of the second set of input audio signals representing the second sound; and analyzing the second set of input audio signals to determine a second relative position, the second relative position being of the second loudspeaker device relative to the first loudspeaker device; and at least one loudspeaker device of the multiple loudspeaker devices comprising one or more third computer-readable media storing computer-executable instructions that, when executed by one or more processors of the at least one loudspeaker device, cause the one or more processors of the at least one loudspeaker device to perform third actions comprising: determining, based at least partly on a position of the user, a reference loudspeaker layout that includes at least a first reference position corresponding to a first audio channel signal of a multi-channel audio signal and a second reference position corresponding to a second audio channel signal of the multi-channel audio signal; determining that the first relative position corresponds to the first reference position; and sending the first audio channel signal to the first loudspeaker device.