Alto Clair supports aptX Low Latency as well as other Bluetooth audio format.
When working with different type of Bluetooth devices (Cellphone, TV, Tablet, PC, Transmitter, etc.), the operation codecs are different, depending on what codec the transmitter side supports.
Alto Clair works under aptX Low Latency mode ONLY when the transmitter also supports aptX Low Latency. (Make sure to use only CERTIFIED aptX Low Latency products. https://www.aptx.com/aptx-low-latency)
You can easily identify the transmission audio codec by looking at the LED indicator when Alto Clair is working, as table below.
Audio delay when paired with different Audio device/transmitter-
|Audio source device or transmitter support-||The audio delay will be|
|aptX Low Latency codec||~ 40ms|
|aptX codec||~ 70ms|
|Fast Stream codec||~ 40ms|
|SBC codec (most standard Bluetooth audio)||~ 220ms|
Note: Audio delay for Fast stream codec is almost the same as aptX LOW Latency codec, but the audio quality of the aptX LOW Latency codec is much better.
Bluetooth Audio Delay Experiment - aptX Low Latency vs others