Hi If you got no luck with glueing the speaker search the net for "Scan-Speak Discovery D7608/920000" This is the right replacement and you can buy it new. Had similar issue but with burned voicecoil, no repair possible. Kind regards Christian

Thanks very much for this suggestion Christian. Very helpful to know! At the moment, I am quite sure I will be able to get the mid-tone driver alive and well again. So I will proceed to find the appropriate glue for attaching the dome back to the tape on the metal ring of the mid-tone driver. If you have an advice about the right type of glue, I am open to hear.

Surely the ScanSpeak mentioned is the replacement for the later midrange unit with the black dome? The picture above is the earlier unit with the clear dome, which is not the same. As an aside, is the ScanSpeak an exact replacement for the later unit? I'm tempted if so as I have another noisy midrange driver on my MS150.2s. To the OP - for glue I would just use standard PVA. It allows for easy positioning and will hold the dome in place fine when it sets.