View Full Version : Help designing boxes.
09-13-2005, 10:29 PM
I need to design a box for my 15" DB pl15d2 2000watt RMS DBDRIVE platinum series subwoofer. I think it should be between 2.9 and 3.1 cubic feet, but some things that i need help with are port size (and port design) and wether I should make it bandpass or not. Also What should my 15 be tuned at?
I also have plans for 2 boxes for my 8's. I have two 8" Rockford fostgate punch stage 2's the RF website reccomends .25 volume per speaker so I plan on making my box .509 which would be 10(H)X24.5(W)X6(D) it will be a sealed box and should be one open chamber. The reason i said 2 boxes is because I have 2 more of these 8's in the mail. (shipped ups from seattle should leave tommarow) So i will have one box 2 speakers.
I think i pretty much have the plans for the 8's down, but it's the 15 that I could really use the help with.
09-13-2005, 11:03 PM
what are the specs on the sub. some of this isn't needed to design the basic box, but i like to see it to get an idea of it's mechanical capabilities which i like to consider for box design.
total coil lenght
what music do you listen to, what kind of performance charictaristics are you after? being that you will be running 4 8's, i would suggest concentrating on 60hz down and tune for boom with the 15. what vehicle is all this going into?
09-14-2005, 07:10 AM
2001 silverado extended cab
· Dual 2ohm Voice Coils/Dual 4 Ohm Voice Coils
· 180oz. Strontium (SR) Magnet
· Rubber Boot Design
· 3" Diameter High Temperature 4 Layer Voice Coil
· Extreme Excursion Motor Structure and Suspension
· Multilayer Treated Paper Cone
· Layered UV Treated Foam Surround
· Dual Spider Linear Design
· Black Textured Anti-Resonance
· Die-casT Aluminum Basket
· Integrated Tinsel Leads for High Excursion
· Push Button Terminals
FS - 24
QTS - .41
QMS - 6.45
QES - .44
XMAX - .79
RE - 6.7
PE - 2000
LE - 92
I Listen to almost every kind of music exept for emo. I listen to alot of rock (nickelback, 3 doors down, evenescense, ramstien) quite a bit of rap (lil john, ying yang twins, 2 live crew, 50 cent, ludacris) lot of country (george strait, toby kieth, rascal flatts) and some techno too.. but mainly rap and rock.
I'm basically wanting a daily driver spl setup. I'm aiming for the loudest system in my town of 12,000 and right now theres 1 guy that's definately louder and one that's pretty close. (the first has eight 12" kicker comps powered by a memphis 4000d, and the second has four ten in Rockford stage 2 10's powered by some kind of rockford amp.)
The box I have right now i just got off a friend as a temp when i upgraded to my 15. it's HUGE!! I bet it's well over 4 cubic feet and the port is like 17X5 and 27 inches long.
09-14-2005, 09:52 PM
if you want spl to stand up to the other guys,....you have to shoot for pure spl and forget daily. i take it you are ditching the back seat. you need to get on a meter and do a lot of experimenting to get max. it's easy to have a really loud daily pounder. you might look into rear firing the 15's and ports and load off the back wall. this will help your bottom end and a few db's. but fit it how ever you can fit this in if you need to. subs back port firing off the side wall works too. one option is a 3.5 ft^3 box, plus port of 50 in^2, 36" long. that is for each sub. if you want to put them in one box, double the volume, double the port area, leave it 36" long. if you want it a little more strong on the bottom end try 4.5 ft^3, 50 in^2 port, 30" long. either should sound good, the smaller one having a little better sq. both will drop bombs. see if you can forward fire the 8's somewhere for good sq. but also some where they don't get cancellation.
09-15-2005, 07:57 AM
Yeah, I want two seperate boxes and I will be leaving my backseat out.
My plans are to flush my rear floor, build to boxes 28 wide ( have around 56 inches between rear door to door) 18 tall (to give me some room to mount the 15) and 20.25 deep. (this i think will give me 3.5^3) I will plan on rear firing with the ports pounding on the rear wall. then I'll mount my 8's (2 per box) above my 15's facing forward. there will be 4 actual boxes but i plan to flush mount them so it appears as one. I would also like to wall off the free space (where the boxes arent sitting wall them in) so it would look better.
The port should be the width of the box which is 16.5 (inside width, counting the mdf it would be 18) and will be 3" tall by 36" long
The 16.5X3 will give the port a 49.5^2
the port will be an L port going the 20.25 in and then traveling over toward the speaker for 15.75 inches.
Does it sound like I've got everything laid out fairly smooth? I'd rather measure twice and cut once.
also what does that tune my port at?
09-15-2005, 09:16 PM
about 30hz. calculated and what actually it turns out to be can vary. but you can tell by watching where you are tuned. 40hz your sub throws, 35hz will throw less, 32 even less, 30 throws a little more,...... it actually came out to be 32hz tuning.
put a 45 degree deflector plate in every 90 degree corner. make sure you do not make it too big, or you will shrink your port area in the bend. also round what ever sharp corners and edges you can. remember to add in port displacement to your box. rough figuring, the box should be gross a little about 4.6 cubic feet, with net vol of 3.5 after you account for everything (sub, port, brace, etc).
09-15-2005, 11:11 PM
alright thanks for all your help. and should the 36" port length be measured from the inside of the L port or the outside? (side nearest the sub or furthest from it)
So with my aim at a 3.5 box i need to make the outside dimensions 4.6 right. well dang i just spent an hour with a sheet of graphing paper, but better re do it on paper then rebuild it at the shop.
29X18X19 would be 4.6 (well close) wouldn't it? I'm tired and I think i calculated for the .75 width of the MDF board. Or is the width of the MDF board included in my 4.6 which would mean that i would want to make it 29X18X15.25
09-15-2005, 11:39 PM
measure down an imaginary center line through the port (not the outside, not the inside).
somehow, i thought you were running 2 15's. but the box specs i gave you were for 1 anyway. i think when i banged my head i got a dose of altzheimers or something. try to make the gross internal volume 4.6.
09-17-2005, 02:23 AM
I will be running two 15's, sometime before christmas. I'm going to finish the box tommarow and I'll pictures up by the end of the weekend. I have to go to tulsa to check out the OSU Okamulgee campus monday (I think that's where i'll go to college) so that will put me back on my install a bit.
09-17-2005, 12:12 PM
get me the outside diameter of the box, the subs info & qty, and such, and what freq. you want it tuned to , and i can get you the box you need, port info and all, and even give you exact cutouts for each piece, so all you will have to do is cut it out and put together.
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