To all the guru's.. Help me design an enclosure!

[pimp86LX]

OK folks. I woke up to a 4x8 sheet of MDF sitting in my shed :super:

Its only 1/2" but thats ok cause im not pushing that much power and i could always make some bracing. I previously built a sealed box but it SUCKS!!

Anyway, I need help in designing an enclousure. I've read tons about sealed vs. ported (my sub can do both) but i really havn't listened to both carefully enough to tell wich is better. I also suck donkey genetalia when it comes to using any vector based drawing program. so the gurus, Please give advice, give some links, post some designs. anything!!

p.s. I've got carpentry glue, 2" woodscrews and a counter sink bit. :D

p.p.s ohya its a 12" sub with an extra 1" faceplate type dealie.

- the pimp:pimp:

[88 Accord DX]

ok. we gotta know what the recommended volume is.

and on the port vs. sealed thing. it depends on what you want. ported will be louder but it will be more sloppy bass while sealed wont get as loud but it will be tight an clean.

[87DXHatch]

I need TS specs... so you need to give up the model number and brand of the sub.

Also, ported can be JUST as clean as sealed if you do it right. I had my 12" Eclipse in a ported box before I switched cars and you would be very hard pressed to tell a difference in the sound quality to the sealed box it is in now.

Just realize that a ported box will be a lot more work, but a lot bigger reward afterward. Sealed boxes are simple and easy.

[87DXHatch]

Also, I need to know how much power you're putting into it so I can recommend how much bracing you will need.

[NXRacer]

there's a guy in my area that builds boxes and he has a special port thats rounded and his boxes are KILLER. I've seen him put to shitty ass 6x9's and they hit harder then a good set of 12's in a sealed box. If i remember the name of the port, i'll let you know......They take up a little bit more space then normal boxes, but its well worth it. I asked him if he would be able to cut out a 10" box to fit 12's and he said it would sound just fine. That way it would be able to fit in my trunk..... :lol

[pimp86LX]

1.0^3ft

im sending it up to 350rms continuous watts

its the Sony Xs-121P5

T/S numbers:

RDC: 3.2
Fs: 26.4
Qts:0.42
Qes: 0.44
Qms: 5.86
Vas: 1.96
Mms:219(g)
Lvc:1.2
Xmax(inch)0.3
BL(Tm):16.1

Total Volume:28Liters or 1.0Cu.ft(1728Cu.In)

[pimp86LX]

bump

[87DXHatch]

Well what do you want? Help with a ported enclosure? Or Sealed? Or what?

I can model it up for you but give me some time, I'm a busy man ;)

[pimp86LX]

sealed ;)

I would normally just tackle this myself, but i can't use CAD very effectively and last time i did it I forgot to account for board thickness :rolleyes: so i was probably 0.5 Cu.ft to big

another question. What do you guys cut with? I don't have a lot of power tools, but i can get my hands on a mitre saw with little problems

[87DXHatch]

Ok, there aren't enough specs there to model it up, but that's ok. Here's what I would do if I were you:
I modeled up 1.25 cubic feet in the Bass Box program and it gave me:

13" X 20" X 8" Outer dimensions using .5" MDF.

That would give you very close to 1.25 cubic feet, before displacement, and I would go that far over the manufacturer's specs... it will make it sound cleaner and deeper.

I cut with a circular saw and a jigsaw. Circular saw for long cuts, jig for circles. It works out pretty good, that's how I built my fantastic ported box. I would highly suggest you do some minimal bracing once you finish the box. If you'll find the thread of mine with the pictures of my ported box, that'll give you some ideas of what to do.

[pimp86LX]

Thanks! hey is that the "golden ratio" i keep reading about?

I have a circular and a jig saw. Ill give that a try.

[pimp86LX]

ohya...any tips on drawing the circle? My paper work on the sub says the "basket seat" is 11.5" I don't have a compas or anything like that. I'm kind bewilderd on how im going to acheive this. My printer can't print beyond 8.5 x 11. Could i buy one from a local sound shop or something?

-Thanks

[dXsquared]

string and a pen or marker... tie the string to the pen.. then to a nail.. make the nail your center point... drag the string around in a circle...

Travis

[87DXHatch]

Travis has it... what I usually do, however, is to get a zip-tie, and measure half the distance of the circle I'm trying to draw, then I stab a nail through that point and tack it down in the middle. Then I push a pen or pencil through the hole in the one end of the zip tie and away I go.

[pimp86LX]

hmm i was thinking about that but wasn't sure if it was really feasable or not. Guess ya gotta just take your time.

[87DXHatch]

It's simple:

After you draw the circle, you get a fat drill bit, drill a hole in the circle, then clamp the board down and cut out the circle with the jigsaw, starting at the hole. It's very feasible.

[dXsquared]

kinda OT

what do you think of MA Audio? i can get 2 15's for 100 canadian.. is it a good deal???

its either that or 4 Bazooka CS series 12's

Travis

[pimp86LX]

news flash:

My neighbour just offered to lend me his plung router with a jig


3===D it should make the circle a breeze :D

[dXsquared]

nice and smooth as well!!!

Travis

[87DXHatch]

MA audio is decent... at least their amps and higher level subs are. I dont' know about that line.

However, I would rate them above Bazooka. I don't know if I'd go with so many woofers... I'd just get 1 or 2 high quality woofers.

Routers make circle cutting a breeze if you have the proper jigs.

[pimp86LX]

ok heres what i have so far. If you guys wish to add anything to it (wink wink ;) ) than please do so

Sony Enclosure Design (http://www.angelfire.com/indie/accord/sony.dwg)

Drawn in AutoCAD R14

[87DXHatch]

If you could save that as a JPEG then I could view it, I don't know what kind of file that is.

[pimp86LX]

http://www.angelfire.com/indie/accord/sony.bmp

my cuts are


2 - 7" x 12" (sides)
2 - 13" x 20" (front and back)
2 - 8" 19" (top and bottom)


if thats not right please tell me!

[87DXHatch]

It sounds like you are wanting to put on your baffle board last, in that case I'd do:

2 - 13" X 20" (front and back)
2 - 7" X 20" (top and bottom)
2 - 7" X 12" (sides)

That should be correct. But there's always more than one way to skin a cat... just make sure you measure .25" further than your measurement, so you've got some "error-room" to work with... you can always take away from the box, but you can't really add wood. Once you have it finished, run a bead of silicon or liquid nails around the seams inside to make sure it's sealed up tight. Put some weather-stripping around the sub mounting hole to make sure the sub has a secure seal with the box too.

[Mike's89AccordLX]

I just bought a vented box for my two 12" Kenwood eXcelon 1200W subs 300rms (they're those fiber ones) I paid $128 (tax included)

[pimp86LX]

Originally posted by Mike's89AccordLX
I just bought a vented box for my two 12" Kenwood eXcelon 1200W subs 300rms (they're those fiber ones) I paid $128 (tax included)

heh heh and thats why im building one :D

well that plus im really digin' the whole acoustics/audio aspect.

When i get my construction techniques nailed down (no pun intended) i think i may tackled a bandpass or folded port design.

Does anyone know the skinny on transmisson line boxes? advantages/disadvantages etc.?


87DXHATCH: thats exactly what i was thinking, and thats for showing me an error that for some reason i missed (7x20 instead of 8x19)

[Mike's89AccordLX]

I would love a fiberglass box but I can't do it on my own and it would be too spendy to have someone else to make one.

[87DXHatch]

Originally posted by pimp86LX
heh heh and thats why im building one :D

well that plus im really digin' the whole acoustics/audio aspect.

When i get my construction techniques nailed down (no pun intended) i think i may tackled a bandpass or folded port design.

Does anyone know the skinny on transmisson line boxes? advantages/disadvantages etc.?


87DXHATCH: thats exactly what i was thinking, and thats for showing me an error that for some reason i missed (7x20 instead of 8x19)

Bandpass: hard to design, lots of things you have to calculate, very small margin of error.

Folded Port: Same thing as a ported box... only you fold it when your port has to be longer than can be straight. This is what my box was, it's fairly easy, but you have to do a crapload of calculations.

Transmission Line: very hard to design. There are no calculators or even set-in-stone guidelines for these kind of boxes. There are a few general rules to follow, but beyond that, it's all intuition and guesswork. A couple people have made attempts in trying to make calculators for these kind of boxes, but I don't believe there are any yet. However, these are supposed to have some of the best sounding bass response of almost any enclosure.

Another one to check out:
Horn loaded enclosure: This is another difficult one to build, due to calculations, and due to the fact that it has to be HUGE. I saw a video a while back of 2 6.5" speakers hitting around 155 db in a horn enclosure, but the box was big enough to house most 15"s. I also saw a video of a horn loaded enclosure a couple college students built out of snow and ice... it was insane.

Fiberglass enclosures really are not hard at all, they just command a significant amount of time to fully complete. I fiberglassed an enclosure in my trunk and it took me like 3 hours. After that it hardened and I could have added more layers, but instead I sent it to the local boat-maker to have fiberglass mat and resin sprayed on it.

Mike, what is that box you got made tuned to? What's the net cubic feet per sub? Thanks.

[pimp86LX]

Well its started! I cut the pieces .25" over and sanded it down to the lines i drew. They fit really nicely. right now I have the pieced glued (using carpentry glue) and C-clamped. Tommorow im adding 2" woodscrews per four inches (recessed heads using counter sink bit) then i'll start on the baffle. :D

[pimp86LX]

Yah!! i cut the baffle today. I tried the string idea but it sucked so i sat, had a coffee and tried to think.. then im like DUH!! i cut a jig the length of the radius + 3/8"(for the width of a pen) and drilled a holes on either end were a screw was centered in the board. Voila! perfect circle. :D Its much easier to think in the morning :D

[87DXHatch]

just to let you know, screws weaken the box. The point of having screws is to hold the pieces in place while the glue dries.

[pimp86LX]

How can they weaken the box? I don't trust glue worth a damn

[87DXHatch]

If you have wood glue, it will bond the two pieces of glue together. Hit them with a hammer and the wood will break long before the glue joint does, provided it has properly cured. Screws interrupt the uniformity of the wood, weakening it. The screws won't break, but the wood around them will...

I'm just saying, if you have the pieces of wood clamped together, and the glue dries, there is no reason to add screws. The purpose of screws is to clamp the pieces together for the wood to dry. If you want to add screws, go for it, I'm sure it won't weaken it to the point that it actually causes the wood to break with the sub in it.

[pimp86LX]

hmm i understand what your saying. But yah like ya said im never going to put enough power to it to consider it a problem. I think i'll do it just to ease my mind. I did use wood glue as well :D

[pimp86LX]

ok everything is done. I just beaded silicon-sealer all around the inside and was wondering how long it takes to cure? Im thinking a good 24hrs should do it. I also think i read somewere that silcon sealer, when curring, lets off a harmful gas (for subs anyway).

Can someone clearify this for me?

[87DXHatch]

Depends on the surround material. If the Sony sub has a rubber surround, you don't have to worry about it, but you should still let it cure for 24 hours. If the surround is foam, though, you should definitely keep the sub away from it for at least 24 hours.

The vapor the silicon gives off while curing is harmful to foam-surrounded subs, any other subs will be fine.

[dXsquared]

hmm... what the fuck is a baffle board? i never put any boards in my boxes.. unless its a dual sub box...

im about to build a new box as well... i want to make a ported box... i have a 3/4 inch MDF 4X8 that i got for installing a friends system... i also built the box.. but i have unlimited room

Ill try and find the specs for the woofer... and maybe you could help me out... i want a box that will be loud.. at around 40-50 HZ...

Travis

[dXsquared]

is this enuff??

DC Resistance (Re): 3.34 ohms
- Electrical Q Factor (Qes): 0.70
- Force Factor (Bl): 9.8Tm
- Mechanical Q Factor (Qms): 10.45
- Moving Mass (Mms): 3.53 oz
- Peak Excursion (Xmax): 9mm
- Resonant Frequency (Fs): 32Hz
- Total Q Factor (Qts): 0.66
- Voice Coil Diameter (d): 2-9/16"
- Volume Acoustic Compliance (Vas): 2.925 cu. ft./82.84 liters

[87DXHatch]

Do you have more specs? Also, could you please start a new thread... this one's takes too long to load :D I can help you then

[pimp86LX]

cool. my sub's surrond is rubber but im still gunna wait.

Thanks everyone for helping out, 87DXHatch ;), I'll get some pics when i can.

[A Dawg Jr]

No, you'll get them NOW!!! I WANT TO SEE! :lol

[pimp86LX]

heh heh well i don't have a digi-cam so its a disposable dealie. Im also leaving tommorow for a week of camping&kyaking so it'll be a while.:D


Ill give ya a heads up though: its a rectangle. :flip: