Hi there cheers for that it's Great. I actually already have that active crossover the only reason I asked about he passive ones is because I'm a mobile Dj and I was thinking about fitting the passive ones as well just in case my active crossover breaks lol cheers tho.
I will post some pics up when I build my cubos but I can't decide do I build the 15s or the18s what's better can any body help.
Cubo 15 and 18 act in a similar way when it comes to performance. Obviously the larger Sd of the 18" gives it SPL advantages if the excursion capabilities are equal. This SPL advantage is spread out between the lower and upper peaks in the response. These peaks are still of the same hight as Cubo 15. In other words: Cubo 18 goes up to a dB, perhaps one-and-a-half dB louder as Cubo 15 but the low and high end response is very, if not similar.
My personal choice would be based upon power compression figures and exact T/S-parameters. An 18" might look better on simulations but if the 18" has a 3" VC whereas the 15" has a 4,5" VC the 15" is likely to produce a higher sustained SPLmax. In the end it depends largely on what driver you're going to use.
Sorry for the late reply (vacation started), you can cut them from the left overs. As, even with cut sheet, not everyone cuts the same it's hard to say where to best cut them from other then to make them as wide as possible. I ussually bet on the "missing piece" of 41 cm long and 6 cm wide, down under the 2 other pieces of those dimensions, or the baffle cut out.
I think you might be meaning the braces that go above the speaker against the front panel. I used the ends of the pieces that form the side panels that make the grill mount. I placed them about 20mm either side of the tee nuts at the front of the speaker cut out hole. See the picture link below.
because the end of these narrow panels are already mitred they fit perfectly agaist the front panel and to the speaker mount panel. you then have more bracing for the top panel to stop rattle.