Thanks for all (well, most
) of the suggestions and sorry for the delay getting back.
Firstly, thanks for the flickr photos Stuart.
I did take a look and your recollection of 18mm seems about right to me without full confirmation.
Bill, this isn't to weatherproof them, I sort of already did that a while back using suitable paints and varnish.
To be honest, they're only used when weather is OK-ish anyway, and have covers in the event of rain.
No, the reason for the inquiry is to evaluate how to attach lighting units/lasers to the speakers that I use for the events. A bit complicated to explain here, but essentially I want to mount a couple of units on top of the speakers, but with secure fixings rather than just sitting there.
Rick, these
are cheap active monitor speakers!
One thing I perhaps omitted to mention is that these were bought second-hand, in known-to-be "sub-optimal" condition, for a one-off garden event.
Believe me, I looked at many new alternatives and for what I needed these were much better value - cheaper than most, better SQ, and not much different from figures I was being quoted for hiring.
Sure, the cabinets have black paint all over them, and one of the displays has a segment or two missing, but I switch them off for shows, so no-one is any wiser!
IanP, I like your lateral thinking, but no windows are near where they are usually sited either side of the screen - and my lasers/lights would still fall off
I think I got round the issue anyway by building a combo wood and 3D printed rig that mounts the kit using just friction and a single screw on the rear of the cabinet at the top which already holds the back on.
Regards
Mike