Normally, if you use them together, there will not be any delay. If still there, kindly check the LED indication on TX unit to see if it is WHITE twice / 5s. If not, kindly contact email@example.com.
However, if you use them separately with other Bluetooth devices, please make sure the Bluetooth device you use is aptX low latency supported. (e.g. Avantree Priva iii transmitter, Audition Pro headphones)If you can't confirm this point, please kindly consult with the manufacturer of the Bluetooth device.