So i'm building another box

[HCVP]

Hey guy's, after reading a few reviews on how well the type R's perform in a ported enclosure, i've decided to have a go, this being my second attempt, first was for a 15 inch SoundStream.

Now any help with be great, as i'm terrible with math, and i've even looked at a few box building programs on the internet, and it was like trying to find my way through a maze. Oh, and i even called Alpine, which only requested my post code, and then i put me through to my local retail store, who weren't really able to help.

Now from all the info i've gathered (and please tell me if i'm incorect, because i'm only going on what i've read.) Reccomended internal dimesnions for ported are between 0.75-2.0cu ft. With a 4'' x13'' port. Now how do i choose the dimesnions, seeing as there is a big difference between 0.75 and 2.0cu ft? Will the largest box typically be the loudest? or does the size of the box affect it's tuning? I've read that 32-34hz is a good tune for them, does that sound right to anyone. Also, once all this is done, does the sub have to be tuned at all from either the head unit, or the amp? Thanks to anyone who can help me here

[bezz]

lol I knew it wouldn't take you long to go ported again! As for building ported boxes I'm no help

[HCVP]

yeah i know, i've come to the conclusion that sealed enclosures suck!! Oh and i bought another Type R, so if can nail the dimensions on a box for one, then i'll just build a second..

[acarmody]

Not all sealed boxes suck, My L7s go good in sealed.

What size sub is it? And is it the current model?

[HCVP]

yeah they are current model type R 12's.

[acarmody]

Never mind, I found the data your looking for. Bear in mind that these are the 'Optimal' box specs not necessarily the biggest and loudest. Based on 3/4" (19mm) MDF

[HCVP]

my last box i constructed using 18mm MDF. Is there any benifit in going any thicker?, and does it alter the sound at all? oh and mine are 1242D. If i'm reading that right, they reccomend a 1.3 cu ft Slot port enclosure?

[bezz]

18mm is pretty thick, i don't think any thicker would alter the sound at all. Are you after loudest or 'optimal'?

[acarmody]

No, the 1242 is 1.7 cubic feet.

[HCVP]

Optimul, with a hint of loudest...... So is net volume the volume once the sub is installed?I thought 18mm was on the lighter side, i've seen a few pre-fab's from SoundStream, and they're made from 24mm...Also, does anyone know somwhere i can buy a port from?The only ones i've seen are from american sites. Last time i used PVC piping cut to length, but it was a major pain in the arse to mount them with a flange, i'd like one that just screw in and mounts flush to the box.

[acarmody]

I got a bit bored so I Tried to design a sub box for you. Keep in mind I'm not an expert by any means.
Using 3/4" MDF. With dimensions from specs I posted. Nothing in this diagram is to scale, all hand drawn in Paint, bloody text writing wasn't working for me so writing is dodgy. I worked with sides being 16.5" x 13.5", top/bottom being 16.5" x 16.5", and front/back being 16.5" x 12" obviously front being 1.5" shorter for port. Port runs top to bottom and does a 90 degree bend at the back. Start with bottom lying on bench, stand sides on either side so that sides are on bench (not sitting on bottom), nail/screw/glue together, then do same for top. Front and back go into the gap. I only did that way so that the front and back can be heavily screwed together from all sides.

Sorry about small picture.

EDIT: Actually on second thought, assemble all pieces except the top, then assemble the port walls in the box , THEN add the top. How could I forget the port walls, tired I guess.

[HCVP]

Hey thanks for the trouble you went you. I'm a little confused though about the port, you said it does a 90 degree bend? is that design as i look at it now rear firing? looking at the picture theres a slot port?or is that just a rough marking of where to put the port? And is there any advantage to using a slot port, compared to a tubular port? If i know what type of port, and what size to use, i can have all the sides, top ect cut to size at bunnings, then just assemble them at home..With the dimesnsions you've posted, does that allow for any overhang on the edges, because that's the mistake i made the first time, and it took me forever to figure it out/

[acarmody]

The port is up against the side of the box as this creates the least work. Uses the side of the box as one of the ports side walls. Yes its a slot port, easiest to make IMO, you could make a round port but then you will need a whole new set of dimensions and a proper round port cone, a lot of work if you ask me. A port is a port IMO. As for the 90 degree bend, the port is longer than the box, so it goes from the front of the box to the back and then along the back wall some more.

Yeah the pictures are had to understand, I made them during the ad breaks of some cop show on TV, I love watching people get caught for stupid stuff.

[HCVP]

Ok so with a slot port, sorry once i get it it wil all make sense and i will feel like a dick, always thought a slot port, was just a slot out of the box, but what your saying is, the slot runs from the front of the box(where the sub is positioned, and then to the back of the box, then right angles along the back wall? So to make a slot port, do i have to insert another wall inside the box, against the inside wall, thus making a rectangular port. I think i've confused myself even more now lol

[acarmody]

Yep I think we are on the same page here, yes the port requires a wall, running along that line I put on the top view in my drawing, the one that has the 1.5" marking, that is the width of the port. The 'wall' of the port is always 1.5" away from the side of the box in this case.

A slot port is bassically a corridor of sorts, it allows the sound to resonate at certain frequencies (above the tuning frequencies, in this case 33hz), at least I think this is right. If you just put a hole in the box you would basically have a free-air sub.

[acarmody]

It will be easier with this photo I found. This is a well constructured ported box. These guys have gon for a double layer of MDF on the front of the box, as well as shaping the bend on the port so its less restrictive to air-flow.

[acarmody]

Check out this dude, building a MASSIVE box for a 15" Kicker L7 (thats why the sub cutout is square), yours won't be anywhere as big as this, but the basics are the same. Strictly European Autosport - View topic - 15" L7, ported box tuned to 30hz build yo!

[HCVP]

It will be easier with this photo I found. This is a well constructured ported box. These guys have gon for a double layer of MDF on the front of the box, as well as shaping the bend on the port so its less restrictive to air-flow.

Wow that looks really good, and really complicated!! I would have though it would just be easier to use a tubular port.How do they secure those extra sections of MDF in place that form the port wall? I'm guessing they're just glued into place in that first picture, but what about when the box is all together.

[VZ-Rob]

........Also, does anyone know somwhere i can buy a port from?.....with a flange, i'd like one that just screw in and mounts flush to the box.

JayCar has about a dozen different sizes with flanges $5 - $10

[Tasmaniak]

here is a big one for you....from yours truly...Dual 18s. So, you can't see the bracing that went inside the box...there was a lot of it and you also can't see the vents that are underneath... But to give you a general overall impression of sixe, thats me on top of the box. I'm 6'2" and weigh over 110kg. I'm a man mountain and I can fit inside this box comfortably. It ended up in the rear end of a GMC Yukon.

[HCVP]

I probably should add that these subs will not be going into the VP, nope, the VP is being sold shortly, and were currently awaiting a finance review, with the plans of purchasing a new car. So i might wait and see what we end up with,(the wife's choice there..) then i can take some measurements of the boot, as were planning on buying a much smaller car. Then maybe someone can use those dimensions and come up with suitable design to house the two 12's. I'm looking forward to putting them in a smaller car, in a proper enclosure. I've also ordered 2 x SoundStream LW1.800's to individually power each sub, so there shouldn't be any power issues there

[Tasmaniak]

using those amps, instead of one for each sub, strap them together to run one single load, this way, you only need to "tune" one amp...the other will do what it's told.

[acarmody]

Wow that looks really good, and really complicated!! I would have though it would just be easier to use a tubular port.How do they secure those extra sections of MDF in place that form the port wall? I'm guessing they're just glued into place in that first picture, but what about when the box is all together.

Glue and screws.

here is a big one for you....from yours truly...Dual 18s. So, you can't see the bracing that went inside the box...there was a lot of it and you also can't see the vents that are underneath... But to give you a general overall impression of sixe, thats me on top of the box. I'm 6'2" and weigh over 110kg. I'm a man mountain and I can fit inside this box comfortably. It ended up in the rear end of a GMC Yukon.

Bloody hell, what sort of vehicle did you put THAT into???

[Tasmaniak]

GMC yukon....

[HCVP]

using those amps, instead of one for each sub, strap them together to run one single load, this way, you only need to "tune" one amp...the other will do what it's told.

what do you mean by strap them together? I was going to use splitters, and then run each one individually @2ohms, to each sub.