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View Full Version : do you see any problem with the box design/port position?



blackbonnie
03-26-2008, 10:38 PM
designing my box for the silverado right now, it will house 3 dd 1508's powered by an IA 20.1. two subs will downfire, 1 will fire up. port is tuned to 39hz, with 48in^2 of port area. box is 3.1 cubic feet after port, sub, and tranny hump displacement. my question is will the location of my port cause any problems? and i have been debating with myself, but will i have to wire the one firing up out of phase with the 2 downfiring? box is 55 x 13.5 x 13 external dimensions using 3/4" MDF. anyone see any problems with this or where i could walk into some?

http://i148.photobucket.com/albums/s25/player2007_69/dd1508.png

blackbonnie
03-26-2008, 11:09 PM
ttt

mdillon
03-26-2008, 11:11 PM
itll make noise, other designs may be more efficient though. you tryin to hide em and say your runnin just 1 or what?

blackbonnie
03-26-2008, 11:13 PM
i want them all downfiring but the way there is the hump in the middle i cant have them all downfire

tommyk90
03-26-2008, 11:15 PM
You can't fit two of them on one side?

Or all three in a pyramid shape on one side?

I wouldn't want a sub right next to the port opening. Would cause some turbulence issues. I mean, it would probably work ok, but I would try to fit them a different way just to avoid any issues that MIGHT happen.

xhilr8n
03-26-2008, 11:18 PM
You can't fit two of them on one side?

Or all three in a pyramid shape on one side?

I wouldn't want a sub right next to the port opening. Would cause some turbulence issues. I mean, it would probably work ok, but I would try to fit them a different way just to avoid any issues that MIGHT happen.

agreed

i would think you can fit them all on one side, downfiring, and put the port on the opposite side.

blackbonnie
03-26-2008, 11:21 PM
are you talking about the one firing up or the one below the port?

tommyk90
03-26-2008, 11:22 PM
are you talking about the one firing up or the one below the port?

The one firing up is right next to the port opening isn't it?

That's what i gathered from your pic.

blackbonnie
03-26-2008, 11:23 PM
i will try to see if can fit them on one side downing but one side only give me 20" x 11.5" so i think it would not be possible to downfire all 3 on 1 side. maybe 2 down and 1 up

blackbonnie
03-26-2008, 11:23 PM
yes it is

tommyk90
03-26-2008, 11:30 PM
Put two on one side and one on the other.

blackbonnie
03-26-2008, 11:37 PM
downfiring like that? so all downfiring just 2 on one side and the other below the port? you dont see any problems with it below the port like that? that was my biggest concern due to the port so close the the hump and the little air space

tommyk90
03-27-2008, 12:00 AM
I would rather have all of them downfiring versus one firing up.

Instead of squaring it off, how about fiberglassing over the hump? That would help out airflow a lot.

blackbonnie
03-27-2008, 06:12 AM
yeah i thoguht about that too, but i have never worked with fiberglass on a project that big. the biggest thing i was worried about is air flow getting trapped in the area below the port. it seems to compact. does anyone else think that could happen? i have decided to move the subs, and will prolly do all 3 downfiring with one in the area below the port and 2 on the other side. anyone think that would cause any issues. i might try my hand at fiberglassing later on but right now its just MDF for me. stick to what i know and get some more experience with the glass

blackbonnie
03-27-2008, 09:52 AM
any more opinions, im working on a new sketchup to have in a bit. post what you think

http://i148.photobucket.com/albums/s25/player2007_69/dd1508taketwo.png

here is the new design/sketchup of it? same dimensions as above. port is tuned to 39hz, with 48in^2 of port area. box is 3.1 cubic feet after port, sub, and tranny hump displacement. box is 55 x 13.5 x 13 external dimensions using 3/4" MDF. anyone got an opinion or more opinions on either of these designs.

which one is better? why? and do you think i will run into any problems with the sub being underneath the port like that with only about 3 3/4" or airspace for the pressure to exit? just looking for the best possible option. here is the old design that i was going to go with.

http://i148.photobucket.com/albums/s25/player2007_69/dd1508.png

60ndown
03-27-2008, 10:11 AM
no point in spending time and money building something your not certain will work, 3 might be the problem?, how bout 2 or 4.

i cant tell from your pic where the port is exactly?

and 39hz? why?

you trying to win a comp?

for a daily driver id tune way lower.

adas
03-27-2008, 10:42 AM
no point in spending time and money building something your not certain will work, 3 might be the problem?, how bout 2 or 4.

i cant tell from your pic where the port is exactly?

and 39hz? why?

you trying to win a comp?

for a daily driver id tune way lower.
1 Its above the right woofer
2. Its a DD, they luv 40 hz tuning, I like 38 gives a bit more lowen but doesnt matter.

3. Why would 4 work when he's struggling with 3.

That box should wrk fine as long as you round off the hump edge and it will sound much better then firing one of thm up. Should be a good setup:)

Mr Cabinetry
03-27-2008, 11:17 AM
designing my box for the silverado right now, it will house 3 dd 1508's powered by an IA 20.1. two subs will downfire, 1 will fire up. port is tuned to 39hz, with 48in^2 of port area. box is 3.1 cubic feet after port, sub, and tranny hump displacement. my question is will the location of my port cause any problems? and i have been debating with myself, but will i have to wire the one firing up out of phase with the 2 downfiring? box is 55 x 13.5 x 13 external dimensions using 3/4" MDF. anyone see any problems with this or where i could walk into some?

http://i148.photobucket.com/albums/s25/player2007_69/dd1508.png

Well, for one, you don't want the port to fire to the side because given the width of the enclosure the port is going to be choked off firing into the door/side panel.

Next, what size are the subs since no one asked the question????

And since this is a silverado, most likely an extended cab or full 4 door cab, you mostly likely removed the back seat and if ya did that, you got all the room in the world to change the design and function of the enclosure to work for you.

IMO, side firing ports is the worst option since all the energy is being slammed down low rather than firing up or forward, if the room allows for the port to fire forward.

60ndown
03-27-2008, 11:30 AM
good point, there may be some cancellation issues with subs up and down and port sideways :)

grimreper912003
03-27-2008, 11:36 AM
Well, for one, you don't want the port to fire to the side because given the width of the enclosure the port is going to be choked off firing into the door/side panel.

Next, what size are the subs since no one asked the question????

And since this is a silverado, most likely an extended cab or full 4 door cab, you mostly likely removed the back seat and if ya did that, you got all the room in the world to change the design and function of the enclosure to work for you.

IMO, side firing ports is the worst option since all the energy is being slammed down low rather than firing up or forward, if the room allows for the port to fire forward.

They are DD 1508's...so 8" Subs.

Mr Cabinetry
03-27-2008, 12:53 PM
Well, that being the case if there 8's, that leaves open a world of design options.

If he can higher in height, increase that to a point where the notch for the tranny tunnel is gone by bring the bottom up to clear it by 3", firing all the subs down and fire the port forward by off setting it to one side of the other.

xhilr8n
03-27-2008, 12:58 PM
why would a port to the side not work well?.....i have had numerous setups in my truck, same subs different boxes, etc. etc. , my truck has been the loudest with port to one or both sides. That is of course with allowing enough room for the port to at least have a little area off of nearest panel/door etc. just curious

jason

Mr Cabinetry
03-27-2008, 01:12 PM
That is of course with allowing enough room for the port to at least have a little area off of nearest panel/door etc.

jason

The key words being " allowing enough room ".

having the port opening 2-3 inches away from a wall or whatever imo just doesn't cut it.

I'm not going to argue or debate the point simple because it's more matter of preference given to the function the sub/enclosure designed is to perform.

Since he's giving the port area 48 sq.in. ans since I don't like to assume, I can only speculate for a port that size for the tuning, he's looking for spl and I've built plenty of silverado enclosures and at the width stated, there's maybe 3" - 4" tops that the port would be away from the doors/side panels.

But, hey, if that works for someone and there not concerned, then be happy with it.

xhilr8n
03-27-2008, 01:28 PM
ok, i was just wondering......my setup is around 14" from the door to the end of the port.

60ndown
03-27-2008, 01:29 PM
why would a port to the side not work well?.....i have had numerous setups in my truck, same subs different boxes, etc. etc. , my truck has been the loudest with port to one or both sides. That is of course with allowing enough room for the port to at least have a little area off of nearest panel/door etc. just curious

jason

http://www.installer.com/tech/aiming.html

blackbonnie
03-27-2008, 03:59 PM
okay, i am not going for spl. im going for a daily driver. i made adjustments to the tranny hump displacement and considering i forget that i will be raising the box a little to accomadate the down fire the displacement of the hump got reduced and reduced my tuning to around 38hz. i am tuning and going by what alot of other peope run the dd's at. my seat has not been taken out, it is still in there, but has been raised 3". i dont want to run 2 subs, or 4. i have my mind set on this. now i can change my designs, i havent built anything yet but i wanna be set with a design soon, i dont need anyone to design one for me,but to just answer questions and see where i run into problems. i think i will work on one real quick and fire the port forward and see how that runs

blackbonnie
03-27-2008, 05:05 PM
well heres take three, all same dimensions tuning everything, just 3 downfiring and port firing toward windshield

http://i148.photobucket.com/albums/s25/player2007_69/dd1508takethree.png

how do you think it will work? its really tough trying to incorporate 3 subs together in a small space and still tune it properly, i had to do some planning but i think i pulled it off. let me know how you think it will work and if it would present any problems.

Mr Cabinetry
03-27-2008, 05:22 PM
well heres take three, all same dimensions tuning everything, just 3 downfiring and port firing toward windshield

http://i148.photobucket.com/albums/s25/player2007_69/dd1508takethree.png

how do you think it will work? its really tough trying to incorporate 3 subs together in a small space and still tune it properly, i had to do some planning but i think i pulled it off. let me know how you think it will work and if it would present any problems.

That design should work out just fine and i know for a fact that you got plenty of clearance for the port. All you have to concern yourself with is the clearance for the subs off the floor.

blackbonnie
03-27-2008, 05:30 PM
yeah, my subs will be here today, and i will figure out there xmax, and go from there. the box will end up being tuned more around 38hz, due to me not factoring in the it will be raised off the floor a bit. but you dont see any problems with the sub being that close to the port?

60ndown
03-27-2008, 06:22 PM
2 subs in a correctly designed box will be a much better daily driver than 3 subs in a poorly designed box. also 2 subs with lots of power can be way more dynamic, think of the difference between a 250 hp motor in a car that weighs 4000lbs compared to a car that weighs 3000lbs, everything gets quicker.you could run 2 subs and sell the other, i like your new box much better but i am concerned that 1 sub is very close to the port.

1 other thing,

try to build your box so it can be mounted port back AND port forward (by rotating it 180), that way you can try both ways and see which way you like better.

blackbonnie
03-27-2008, 08:13 PM
i dont see how this isnt properly deisgned. dd recommends these subs to have an air space or .7-1ft^3 each. the only thing i wasnt sure of was with the port being close to the sub, but my last box i had was with a 15" tc sub and that was just as close to the port as this one is and i never ran into any problems so i dont see why i would here. the only thing that i was really concerned about was if the port being to close to the hump would create any air flow problems. thats what i was wondering, and no one has given me a solid answer on that. i mean i personally dont think it will because the air has to always go through somewhere or around something so i dont see why this would be any different the the magnet or baskets of your subs.

60ndown
03-27-2008, 08:53 PM
i dont see the hump/port being an issue, good luck.

blackbonnie
03-27-2008, 09:05 PM
thanks, anyone else got some opinions

Mr Cabinetry
03-27-2008, 10:42 PM
Honestly, if I thought there were any issue's with design, I would of said something.

It's well thought out and designed to fit the way you want it.

However, if the port is a cause of concern in some part, that's easy enough to fix, just make the port 8" width x 6" in height, that gets it up past the tranny hump and makes the subwoofer issue a non- issue.

Phil
Woodlawn Cabinetry

blackbonnie
03-27-2008, 11:36 PM
well it does make the sub an issue, because once i hit the back wall i cant run the port 6" wide due to the limited depth of my enclosure and my port have to run 6" at the back wall. see internally i only have a surface of 19" x 12 " to mount my subs on downfiring. so it wouldnt be possible to have a 6" port and a 7.25" sub cutout on that sheet because it is only 12" deep and that gives me 13.25". i think this is the best overall design for me, and im gonna stick with this one. whats the worst that can happen, i have to make a different one? well ill take the chance but i have thought this out thouroughly and im gonna go with this.

blackbonnie
03-28-2008, 03:06 AM
going once, twice...tomarrow might be build day

60ndown
03-28-2008, 11:08 AM
final ohm load w 3 subs and can your amp do it?

blackbonnie
03-28-2008, 11:17 AM
i have an ia 20.1, of course it is 1 ohm stable. it will be wired to 1.33 ohms. amp can do it, subs can take it, i can build it, can you feel it?

60ndown
03-28-2008, 11:21 AM
i have an ia 20.1, of course it is 1 ohm stable. it will be wired to 1.33 ohms. amp can do it, subs can take it, i can build it, can you feel it?

i know everyone tunes dd subs close to 40hz, but there is A LOT of musical information closer to 30hz (depending on your music tastes) if its a daily box, for music, id like to see it tuned @ 35, or 32, instead of 38.

but its your box.

blackbonnie
03-28-2008, 11:27 AM
well i will keep that in mind, maybe i will change it to around 35-36. i want it to hit real low, but i here that even around 40hz alot of people are very pleased with the lows

60ndown
03-28-2008, 02:34 PM
well i will keep that in mind, maybe i will change it to around 35-36. i want it to hit real low, but i here that even around 40hz alot of people are very pleased with the lows

alot of people are 15 years old and never heard......'felt' 26hz, with autority.

most people make the change from spl as kids to sq as adults.

then there's us 'adults kids' that like sq at spl levels.:veryhapp:

blackbonnie
03-28-2008, 03:02 PM
so what do you recommend, i mean can these subs really hit the lows that well? i dont want to have high expectations but your making me feal like i need it. what would you recommend me tuning to

60ndown
03-28-2008, 04:42 PM
so what do you recommend, i mean can these subs really hit the lows that well? i dont want to have high expectations but your making me feal like i need it. what would you recommend me tuning to

cant help with dd subs, i know they love the power and get loud, but if you want as much sq out of em as possible your gona need to talk to someone who knows / understands dd subs.

im sure you'll be happy either way, you got great subs lots of power so your going to have fun.

maybe start a new thread?

"how low can i tune dd 8" subs" :crazy:

adas
03-28-2008, 06:19 PM
cant help with dd subs, i know they love the power and get loud, but if you want as much sq out of em as possible your gona need to talk to someone who knows / understands dd subs.

im sure you'll be happy either way, you got great subs lots of power so your going to have fun.

maybe start a new thread?

"how low can i tune dd 8" subs" :crazy:You dont have experience with em, they really are different with tuning then other subs. I had my 3 1508s tuned at 39hz, lows were crazy, and the box was a bit small. My box for 4 of them, little large tuned to 37hz and while it DOES drop off below 30hz because of almost no port loading, everything above 33hz sounds like the box is tuned to 32hz or so. My box peaks at 39hz in my car, and at 36hz i hit a 140.3 legal, 142.7 at 38-40hz. Thats not bad for lows to me, at least for 8s:)

I really wouldnt tune lower then 37-38, the subs then have wierd freq response in the 60-70s.
GET HER BUILT!:veryhapp:

blackbonnie
03-29-2008, 11:08 AM
sounds good, thanks guys

60ndown
03-30-2008, 11:58 AM
finished yet?

howzit zound?

blackbonnie
03-30-2008, 12:02 PM
not yet, im shooting for next weekend. i had to make some minor adjustments in dimensions but it will still be the same specs. look for a huge build log to be coming. i have been doing alot to the vehicle and will make one coming up. ill keep you posted