This should be interesting.

[rosshimself13 10+ year member]

The qtc shows to be around .79 not the desired .7 being tuned to 45 I think it'll turn out ok. //content.invisioncic.com/y282845/emoticons/hide.gif.2d479cfd917eedfe201353b91522ceab.gif I bought 3 sheets of mdf today.

Also if anyone cares I'll try to take lots of pictures. This is my first build of anything close to this magnitude it might be a total failure.

 

[bbeljefe]

If the specs on the woofers you have are anything like the IDMAX 15, they have an EBP of about ~39, which is great for sealed and 4th order. If they're like the IDQ, then EBP is ~69, which is a little better suited for ported and 6th order.

Of course, being a custom built sub, you'd have to have access to a DATS or you'd have to spend some time pulling the TS numbers manually in order to know for sure.

As for the box, the 1:2 ratio is fine and the tuning sounds fine too, although I'd want to tune it closer to Fs.... whatever that may be. However, being a 15, I would assume it's below 30hz, so I'd want to be around 32-4hz. But that's subjective, unless the speakers won't perform well in that box at that tuning. Again...need TS.

Bracing with ½" all thread is fine for short dimensions but if you get past 20" or so, I'd be afraid the ½" would be too thin to resist inward pressures. For longer braces, I'd use 3/4" and the biggest fender washers I could find. The last thing you want is a brace in the box resonating like a guitar string.

 

[rosshimself13 10+ year member]

Being so rare t/s parameters aren't available image dynamics couldn't tell me anything but I'm gonna jump head first into this and if it doesn't work then I learned an expensive lesson.

 

[bbeljefe]

You could always build a 4th order for one of them and test it's performance before jumping head first into a complex build. Surely you could sell a good test box to someone for enough to at least pay for materials.

Or, you could ask around and see if someone in your area has a DATS unit. I'd be happy to test them for you but shipping woofers back and forth for pulling parameters would be too risky, not to mention the freight costs.

 

[rosshimself13 10+ year member]

Oh and most bracing will be mdf, just going to do 4 pieces of all thread from top to bottom so ~16" that will hold the box to the truck well and effectively brace it correct? I mean yes it's kinda heavy but it's tied to the bed using utili-track