B&C Sub 15 External Cut Outs

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   Hi, 
I'm reaching out for help - I was wondering if any math wizards can break down the individual external cut out of the b&c sub 15 plan (18" thickness), similar to the mk1 staiper ms18 speaker plan available on the internet.

photo can be found here: https://i945.photobucket.com/albums/ad298/jez_milner/0-Misc/B-and-CSub15STD.png

if the link doesnt work you can find it in here: 
https://forum.speakerplans.com/bc-sub-15_topic77554.html

Edited by kaps - 26 February 2026 at 3:08pm

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
kaps Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 March 2023 Location: Leicester Status: Offline Points: 6	Post Options Post Reply Quote kaps Report Post Thanks(0) Quote Reply Topic: B&C Sub 15 External Cut Outs Posted: 26 February 2026 at 3:07pm
	Hi, I'm reaching out for help - I was wondering if any math wizards can break down the individual external cut out of the b&c sub 15 plan (18" thickness), similar to the mk1 staiper ms18 speaker plan available on the internet. photo can be found here: https://i945.photobucket.com/albums/ad298/jez_milner/0-Misc/B-and-CSub15STD.png if the link doesnt work you can find it in here: https://forum.speakerplans.com/bc-sub-15_topic77554.html Edited by kaps - 26 February 2026 at 3:08pm

DMorison Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1740	Post Options Post Reply Quote DMorison Report Post Thanks(1) Quote Reply Posted: 26 February 2026 at 4:24pm
	Hi there, I think you meant 18mm thickness, not 18", right, otherwise that'd be a very heavy and thoroughly impractical cab... Bottom & top: 436w * 656d (allows 30mm grille clearance - increase if you want to put in modern very high excursion drivers.) Sides: 550h * 656d Back: 400w * 550h Baffle: 400w * 450h Port Shelf: 400w * 382d (sits behind the baffle) Port brace: 100h * 400d (sits underneath and flush with the front of the baffle). I'd strongly recommend at least a bit of bracing too, eg a vertical brace ~ 100mm deep from the port shelf to the top of the cab, one from that to the back of the cab and one fron there to each side. Be careful to figure out where you want to mount your handles before finalising where to put the side braces. The difference between the internal volume whan built in 18mm timber vs the original plan's 19mm isn't going to be big enough to matter so I haven't changed anything to account for that. Likewise the kind of bracing I proposed won't take up enough internal space to be a problem. HTH, David.

kaps Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 March 2023 Location: Leicester Status: Offline Points: 6	Post Options Post Reply Quote kaps Report Post Thanks(0) Quote Reply Posted: 26 February 2026 at 4:45pm
	Hi David, You are an absolute legend. Really appreciate your time. I'll get building over the weekend. Kapil