beerman

You'll need some steep filtering if you use those References in a two way setup. At least a 3rd order. They ring like mad in the upper reaches. They should be great for a 3-way, a low crossover point should be enough to control the cone.

28 cubic feet in what vehicle? :eek:

I was playing with the ceramic magnet Tang Band 8 in a "max flat" box and got a labrynth with no fewer than 6 panels in it. That woofer wants a small box and low tuning. 60% of the box was port. I wanted to use it for my PC subwoofer, but decided on something smaller. It will do an L-shape and even a straight port, but it depends on the application. If it doesn't fit with a straight port or an L-port, it makes a labrynth.

You could raise your tuning frequency, but then you don't get what you want. The other option is to reduce xmax, but that means chuffing.

You'll get the same results as the carstereo.com calc if you use the formulas from http://www.diysubwoofers.org There are more advanced formulas that will give you the same results as WinISD if you built an excel spreadsheet for them. But why bother? You can fire up WinISD and let it design one for you. The long of the short of designing a bandpass: start with a sealed box where Qtc = 0.7. Determine Fcb. Build an equal size ported box in front of this where Fb(ported) = Fcb(sealed). Fb just determines port length and part of port area. Remember to include port displacement when you design the box. That should yield a relatively flat response one octave below and one octave above Fb. 4 fifteens = big box. Easily 30 cubic feet of cargo space needed in the vehicle if designed for a healthy balance between SPL and bandwidth. Roughly 12 CF sealed, 12cf ported + woofer and port displacement. This isn't something you'll be able to do alone, that's for certain.

I've moved my forum to http://www.subwoofertools.com/forum/ Calculator can be found here: http://www.subwoofertools.com/forum/ported-box.asp I'm working on a new improved calc. It currently only does response curves: http://www.subwoofertools.com/boxprogram.asp www.accelerator-pedal.com should be returning my custom 404 page directing you to subwoofertools. It's not. Stupid GoDaddy hosting. :mad:

Have I responded yet? My email is all kinds of whacky with my spam filter more sensetive than a $20 car alarm.To everyone: the original algo looked for either 10 square inches of port per cubic foot or a 9:1 ratio between height and width, whichever is greater. I designed it for newbies with low-powered woofers to make the smallest possible enclosure that fits the user's desire while minimizing port noise. Least common denominator, dumbed down, etc. Version 2 is available, fixing the "2 cubic foot tuned to 18hz makes a whacko port" issue and allows for 50% more port area through a "High SPL" option. I also have a thread at my forum for version 3 suggestions. Since four people in total (literally, including myself) post to my forum, I have a clone thread in Sounddomain's subwoofer solutions forum**. The two most requested suggestions are a double baffle option and for the user to input desired vent area. Since my original target users are newbies, I also have plans for a mini-calculator for driver basket/magnet displacement. ** I don't want to poach forum users, so feel free to leave feedback here, too. I check my server's referral logs weekly.