As part of MusicCast there are a few options to work around delay...

Step one, the AV products (receivers / soundbars), WXA/WXC, MCRN470, RN803 etc all have an option to switch between 'audio sync' and 'lip sync'.
If you're trying to link via a soundbar or theatre receiver - to a speaker in an open plan kitchen, the sound may be delayed.
If it is, switch from 'lip sync' to 'audio sync'.
This will delay the audio in the main room so it's in time with the kitchen speaker.

If this is an audio+visual source, you may see a lip-sync issue on your display.
If this is annoying for this content, switch it to 'lip sync'.


Now, if the products are hard wired, switch them to 'speed boost' via the MusicCast app. 'Standard' will have a delay, but it works well with WiFi, 'stability boost' will have a large delay and should only be used where WiFi is dodgy... and if that's the case I'd assume you'd be installing an AP anyway.


If you're just using the standard 'zone 1' / 'zone 2' feature of a Yamaha AVR, then 'party mode' gets rid of the delay, but it switches everything to all channel stereo.

Other things that reduce delay, taking off extraneous audio processing.
Using analogue sources over digital sources.
Planning a system where two zones are so close to each other that it's almost pointless to install them.