Geo, you will probably be able to help me the most since i am kinda stealing your design , it is based off your box for 8 MTX subs in IB. i can go 46"W, 21.5"H, and anywhere from 12"-18"D, but i would like to keep it around 4^3 total internal volume. The box is for (2) 12" XXX with the port down the middle instead of off to the side like most boxes, so basicly it will be like two small slot ports (1 for each sub) that meet in the middle to make one large port. I would like to tune to ~28Hz +/- 2Hz. The smaller the box the better, so no 10,000^2in of port area guys , just what i will need for a daily driver. My problem is i just can't seem to get the right port length, i must be doing something wrong. Every time i try to calculate it says i need about 10 feet of port length :unsure: , so any help will be great.
or, if the port is just going to be ungodly long so that it wouldn't work, please suggest alternatives. This is my first slot port, so i'm gonna need a lot of help.
Seperately, I'm seeing 3 1/5" high, 4" wide, and 19" deep (you can pull that off if you do a bent port). Together, we have 4 cubes even tuned to 28hz with a port that's roughly 6 1/2" high, 4" wide, and 19" deep (we're just putting the two together). That leaves you enough room for the drivers. Jeff
that is what i was afraid of, for the size i wanted on the port it will be way too long. Jeff, can you check out the thread on CAF ( http://www.caraudioforum.com/showthread.ph...threadid=171022 ) and see what you think about those measurements. I just need someone to double check my measurements, DooDaddy an i figured that with a 20" tall and 3" wide port it will be 44.95" Long OR 31.17" Long. It just depends on if WinISD automatically accounts for port area inside the box or not, so i just need to know which to choose. I want to do my origional idea, but with how this is all turning out it just isn't practical. Thanks for the help. OR if you just want to do it yourself: Box is 21.5"H, 46"W, 13"D with .75MDF. I want the port 20"H x 3"W and however long. Just one port this time still tuned @ 28Hz.
8" high, 6 1/2" wide, and 16 1/2" deep (again, you can bend it). 13" across per sub, so that's 26", + your 6 1/2" comes out to 32" across. You have plenty of room up, down, and back. Jeff
WinISD does not account for the port displacement inside the box.... So I'm guessing that would mean it's the 44" long one. You have to recalculate the internal volume after Driver and port displacement
lol, you are one confusing man today jeff, you keep leaving out that important info . Remember, this is my first slot port, you kinda gotta hold my hand today HAHA. I wanted 20" tall and 3" wide for ease of building, but you keep ignoring that so i'll take that as your way is better. On that last port you mentioned, is that for the 46x21.5x13 box and 1 port, or 2 ports, or a different box and x number of ports?
Just playing around with WINISD, and your woofers, I seem to come up with a 14" length of port, with a box 4cf tuned to 30 Hz (Adire recs 30). Port height is 10" x 2.5" W. This may be totally wrong, but that's what I came up with.
I sowwy sweetie. I didn't see your 3" x 20" port remark. In all of my comments, I'm keeping your outside dimensions in mind. In the 1st post, I did it with respect to each sub and it's individual enclosure (you're doing seperate chambered, correct?), then I just combined the two together to get the total enclosure. I actually messed up, and put 4" as the combined two ports, instead of the 8" that it should be. On the second post, I did for the whole enclosure, using 1 giant port (or the two put together). Also, Focal Enthusiasts is correct too. He's just tuned a bit higher, (30hz I wanna say?) which is cool because you gave us a +-2hz variance. Jeff
Not a big deal... I know exactly what you are trying to do. B) Essentially, what you are going to have is two 20"tall, 1.5" wide slot ports coming from each half of the enclosure, merging together in the center to make up a 20" tall, 3" wide slot port. With a 4 cu.ft. box, when I put in two 20" tall, 1.5" wide slot ports, WinISD is telling me you'll need to make those approximately 42.5" long to accomplish a 28hz tuning frequency. For a 30hz tune, bear in mind, the lengths drop to 36" - much more reasonable without much of a change in response. B)
He's essentially doing a box like this one: The Eight Sub Quad-Isobaric Slot Vented box You can see what looks like one port from the outside actually splits into two ports inside. Doing a slot-vented box like this, with a floor-to-ceiling slot vent is a favorite of mine, because effectively the slot vent also works as some pretty extreme bracing, not just for the very important front panel (baffle), but also the top and bottom panels. B)
