DLNA has the best sound quality.
To be more objective, DLNA delivers the original sound most accurately.
DLNA can transmit the original sound as it is, but Airplay and Bluetooth decode the original sound (PCM) and then encode it back into a codec suitable for transmission, which causes loss of sound quality. Specifically, Airplay always transcodes to 16bit 44.1Khz ALAC, while Bluetooth transcodes to 328kbps 48Khz SBC. LOSS can occur during this transcoding process.
In fact, even in the case of DLNA, if the format of the media to be transmitted is not supported by the client, the client may encode and transmit in real time in a format that the client can support. However, the ROSE device supports most audio codecs so you can always listen to the original sound.
Which sound quality is better, DLNA, Airplay or Bluetooth?