Unfortunately, I cannot answer this question because I only use the hard-wired speakers. From my point of view, however, it makes little sense to use wired and BT speakers at the same time, because even if the BT transmission works without delay, the time of flight of the sound in the air (direct and reflected reverberation) has a disturbing effect either way, and in my opinion a good stereo experience is no longer given.

I don't notice any delay and any delay that does exist doesn't interfere with my listening experience....