fogged306

Sweet, that's exactly what I was looking for. I wasn't thinking along the lines of the 45's so I'll have to see if doing it that way will allow me to stay within my dimensions, but essentially that's just what I'm trying to accomplish. Thanks for the info, I def appreciate it!

Is it possible to to a T shaped slot port? I'm designing a box right now with 2 woofers and no divider. I was planning on making a L shaped slot port off to one side of the woofers, but got to thinking about putting the port in between the woofers and making it shaped like a T without a divider in the middle. No clue if this would work or if the velocity of the air coming from each side would create turbulence where they meet and make the port less efficient. I would put a divider in but I'm limited on space and a divider makes the port length longer per side and cause me to increase the size of the box to stay optimum and the dimensions are larger than I have to work with. So I'm stuck with both drivers using the same enclosure space and port... This is purely an aesthetics question because I think boxes look a bit goofy with 2 woofers next to each other and a port off to one side.

Thanks for posting that picture. I didn't know there were carriage style bolts like that. Those will definitely come in handy. Yea It's particle board underneath... Does mat and resin adhere to particle board better than plastic?

I'm curious as to why you said corvette body panel adhesive. Is that different than regular panel bond? I know corvettes are all glass so I'm assuming it's specially formulated for bonding glass, but just curious nonetheless. Mainly because I have panel bond at the shop already.

Yep, this doesn't sound like a good project to learn on. I definitely appreciate the replies. I'm glad I asked before I went and ordered everything and tried it out first.

I want to leave the top part factory, so I don't want holes in it. I basically want to do a stealth fix where you wouldn't know it was done unless you lifted up the tray and looked underneath. I get what you're saying though and it makes sense. I guess worst case would be to drill the holes and then re-carpet the top. I'm trying to get my feet wet in fiberglassing and I think this would make for a nice first project to experiment on, otherwise I wouldn't waste my time on this thing. Appreciate the insight though,

This has nothing to do with audio, so if this is in the wrong section, I apologize and feel free to move it. The package tray for my hatch was broken when I bought the car. Looks like someone put something too heavy on it and cracked the structure inside. Can I lay chop mat down on top of the carpet and resin it or will the resin not adhere to the carpet? I'm just looking to do the underside of this to make it rigid enough to hold it's shape again when it's in the car. I've heard you should lay rope or something similar to give the mat a corrugated look for linear strength. Here's a picture of the underside of the tray where I'd like to strengthen it. The carpet is hook and not straight cut if that makes any difference.

If I add or subtract 3" from the port the frequency changes by less than 2Hz and about 1dB in either direction from where it is now. I'm assuming this is one of those scenarios where it's not something I would be able to notice, right? Also, I have 71.92 fps port velocity if I design the box the way I would like it to be with 2 chambers and the exact fit I would like, is that something I would hear at all in the hatchback? This isn't a kerf port, it's just going to be a slot port with the inside edge router'd and a double router edge on the inside beginning of the port. I always make my boxes with a lip around the front and back edge mainly because I like the look. Here's a picture of one I built a while ago, and I would like to keep this look, but with a higher FPS on the port, should I not do the lip and router the port exit instead, or does it not matter? Thanks for the replies so far.

So I've been reading and watching videos and have learned the basics of winISD I think. I've got the loudspeaker design cookbook on it's way, but in the meantime, I have some more questions. I'm going by Sundown's suggestions and using 2.0cu ft per driver and tuning the port to 35Hz. Maybe I'm not playing around with dimensions enough, but to get the required port area in that size box with one driver I'm going to have to either double the port back on itself a hair, or the interior end of the port will be very close to the wall. What are the rule of thumbs for how close you can get to the wall. This is mostly because I'm trying to keep the fps of the port to under 70 so the opening has to be around 2" with my box dimensions, which are 17.375W x 18.5H x 14.35D internal with a 2 x 18.5 x 30.xx length port. This is also based on using 750W RMS for a single driver. I'm using a SAZ 1500D at 1ohm on two of these subs in the back of an MK4 2 dr Golf. My main question is this, do I need to separate the subs? I'm basically designing these boxes as individual boxes so there's a divider inbetween them and each sub has it's own port. I noticed that if I make it so they both share the same volume, the port length doesn't get much longer if I double the width of the port, in which case I can easily fit one single slot port for the two woofers and still satisfy the total port area required for 35Hz. What's the drawbacks to having 2 drivers share the same enclosure space? The goal to this set-up is to be loud on music, mainly rap and bass cd's so I can use this as a demo car to sell product.

Thanks for the replies so far. I'll pick up a copy of that loudspeaker design cookbook and I'm going to check out that video right now. I guess I was looking for just a simple program where I put in the T/S parameters and it spit out a volume and port area. Looks like it's not going to be all that simple though.. I should say that I'm not looking for absolute perfection, but just something that will outperform a pre-fab for any given speaker. And thanks Impious, I was going to ask if xmax was peak to peak or one way but forgot to in my first post.

I recently opened up a tint shop and have had a lot of customers wanting audio, so I just picked up the Sundown line. I've been an installer for 14 yrs now, but all the shops I've worked at did cookie cutter systems with pre-fab boxes so I never really learned how to make a box and match it to the subs. I've built plenty of boxes, so the actual building is not what I'm looking for it's just getting the correct size and port length I need. I see a lot of threads recommending box calculators like torres ect. which I've downloaded, but I don't see how you're converting the sub specs to box design. I found the AJ vented designer program which does this (I'm looking to built mostly vented enclosures) but I'm getting huge difference in box sizes between the 3 options it lists for alignment. SBB4 is giving me .9 cu ft and qb3 is giving me 3.7 per sub and SC4 gives me 1.83. The port size and length are excessive as well when I put in the xmax for the sub like 10" round by 170" long for SC4 for example. What am I doing wrong here? I'm inputting the specs right from the sheet for the SA-12's I'm using. Qts .52 Qes .58 Fs 33.71 Vas 21.21L Diameter 12"(or 30.48cm) xmax 38mm and I've been playing with port diameter but it always seems the smallest number before it warns you the port is too small also gives you the shortest port length. I'm also looking to convert this to a slot port. So basically what I'm looking for is some direction on where to find box software that I can use or if this one is good, how to use it, and how to convert to slot port sizes. Any other knowledge you'd like to share with a rookie designer would be appreciated also. Thanks. Also wouldn't mind some advice or links to some good reading material for this. I've been to this website and done some reading http://www.bcae1.com/spboxnew2.htm, but I'm always looking for new ways to learn and new stuff to read.