Hi everyone! Thanks for this interesting thread, and thanks Josh Ricci for this brilliant design! I've red the thread multiple times last year and i'm reading most recent posts today. Now i'm actually looking forward to build my first pair of Skrams! 🥳
First of all, i would like to make a slight change in the port layout, using 2x18mm braces (instead of 3x12mm) to match the double braced horn mouth. On paper this should make no change in port tuning, as it would not alter the total port area.. it would obviously limit low tuning options (having one vent duct less to block) but it won't be a problem for me honestly.. i'd rather be more worried about having less bracing on the port, but in my experience 2x 18mm panels should be enough to brace a 600mm surface.. never built a cab for a strong motor 21' driver though, so please feel free to give your opinion about any nasty consequences this mod could cause!
i'd like to use B&C 21DS115 8ohm, but i've also considered the SAN214.50 cause it is way cheaper and i've seen many are using it with good results.. no chance they would match B&C quality, but it seems they are worth their price.. 8ohm impedence would be my choiche anyway, as i plan to build two more subs in the future and run them parallel, 2 drivers on each channel of a 2ch amplifier. Amp will probably be a CVR D3302 which i've seen used succesfully by Jay (props for you mate, and congrats for your system development, you did a great job).
I already have some baltic birch ply and i'm lucky enough to have a friend who works as a full time carpenter and CNC operator. We both have some experience in speakerbuilding. We just have to find the time to draw the box on cad and make some long awaited sawdust.
If there's any advice you guys feel you can give me, i'm all ears! Cheers!