# Designing Single Cab Ported Truck Box



## Brad92

Hey guys,

I have researched this some and wanted to get some ideas. I have an 02 GMC single cab truck. Right now, I have 2 Kicker Comp12's in sealed boxes being pushed by a Kenwood 500w rms mono amp. I miss the sound of my old MTX 10 in a ported box; it was crisp and clean powered off the same amp. I wish I would have gotten 2 10's instead of 12's due to airspace, but I didn't listen. My truck is loud and sounds decent, but I know there is more potential.

Anyway, I'm looking to build a custom ported box for my 12's. I have woodworking experience and am not worried about actually building the box, but I am not sure on the size or type of port. I was wanting to go with a slot ported design. 

Has anybody done something like this in a regular cab truck? What type/size/number of ports should I use? 

Any info would be appreciated.


----------



## Ray21

Kickers typically take a larger box... so ported they'll need from 1.5^3 or more each. 

I'd go with a single slot port or pair of 4" round flared ports if possible. I had a single 12 in my old single cab truck with the port firing toward the driver's side... worked great.


----------



## Brad92

I did a rough box design and the closest I could get was around 1.3 cubes per sub not counting displacement or the ports. I'm also not sure if I should build it with a single chamber or split it into 2...


----------



## Brad92

I used some calculators and came up with 1.3^3 ft per chamber including the slot ports and have it tuned to 35Hz. I have it designed with a slot port for each chamber. Is this the best way, or should I just make it one large chamber with one large port? Also, I was able to get the airspace by figuring 1/2in MDF and brace it internally as opposed to 3/4. I would think that would be stout enough, but I'm not sure...


----------



## adrenalinejunkie

If I was in your position, I'd go with one big chamber since ported dual chambers will take up more space. Some don't like using one big chamber since a faulty driver "can damage the other one."


----------



## Brad92

Ok, and is there any difference between using say a 2 small slot ports on each side, or using a really wide one, but not as deep in the middle with the same area?


----------



## Brad92

Here's my progress so far:

I still need to add the 2 sections for the ports, cut out the holes for the subs and install the terminal cup.









Side view:









Rear view showing notch to fit under the rear window trim:









I can't find my jigsaw, so that's holding me up on the sub cutouts. I'm also waiting on speaker wire and the terminal cups from eBay.


----------



## airseeker

hell it looks good to me so far, But I do think I would have gone with a single chamber... but I guess its not that of a deal, you coulda ended up with a hair more space if you went single chamber single port... but it does look good and semetrical lol


----------



## minbari

airseeker said:


> hell it looks good to me so far, But I do think I would have gone with a single chamber... but I guess its not that of a deal, you coulda ended up with a hair more space if you went single chamber single port... but it does look good and semetrical lol


actually he would have gained alot of space by going common chambered.

ex: 1.3 cuft tuned to 35 hz requires a 4" x 4" x 24" port. So that is 378cu in of port volume for each box. total of 756cu in for both enclosures. A 2.6 cuft box requires a 4" x 4" x 10" port. which is 163cu in total for both speakers. that is a difference of .2 cuft of port displacement for just 1 enclosure vs .09 cuft for both.

there are advantages of seperating the chambers, but when you need space for a tight install, common might work better.


----------



## Brad92

Thanks. My caulking is terrible, but you'll never be able to see it.


----------



## Brad92

minbari said:


> actually he would have gained alot of space by going common chambered.
> 
> ex: 1.3 cuft tuned to 35 hz requires a 4" x 4" x 24" port. So that is 378cu in of port volume for each box. total of 756cu in for both enclosures. A 2.6 cuft box requires a 4" x 4" x 10" port. which is 163cu in total for both speakers.
> 
> there are advantages of seperating the chambers, but when you need space for a tight install, common might work better.


So if I used that port size, could I have done a 4x10x4 center port? Or you can't change the length even though its the same area?

And what would be the benefits of one chamber vs two chamber other than less port volume?

This is my first box, so I'm just trying to do the best I can.


----------



## minbari

Brad92 said:


> So if I used that port size, could I have done a 4x10x4 center port? Or you can't change the length even though its the same area?
> 
> And what would be the benefits of one chamber vs two chamber other than less port volume?
> 
> This is my first box, so I'm just trying to do the best I can.


no ,if you change the port area, it changes the port length. so if you went with a 4" x 10" port, you would have a single 28.5" length port.

for a pair of 10" subs with 500watts of power a 4" x 4" would give you about 118 ft/ sec port velocity, that is a little on the high side, but wouldnt be un-usable. if you changed it to 4" x 5", it would make the length 13" and port velocity to 94ft/sec. (ideally you want it less than 100 ft/sec)

where you put the port is not very important as long as you have proper clearance at the exit. you dont want the port sitting right up against the side of the cab.


as for advantages, that is really it. if the box you have biult is large enough, there is no sense in rebuilding it. just remember that the port volume (LxWxD) needs to be subtracted from the gross box volume. so if you had 1.3 cuft of space and .2cuft of port volume and .1 cuft of speaker volume, you now have a 1cuft box


----------



## Brad92

I didn't realize the port size would be that much smaller on a single chamber design... I'm probably going to finish it and install the subs to see how they sound and maybe change it if I don't like it...


----------



## Brad92

Does box shape have anything to do with how it will sound? If I put a port on the passenger side, will that shallow center section have any effect on the sound?


----------



## minbari

Brad92 said:


> I didn't realize the port size would be that much smaller on a single chamber design... I'm probably going to finish it and install the subs to see how they sound and maybe change it if I don't like it...




ya, the smaller your enclosure the longer the port gets for a given tuning freq.

this is why you dont see many 6.5" or 8" very small ported boxes. to get a .5cuft box tuned to 30hz would require a single 4" port that is 72" long  you could use a single 2" port only 17" long, but it would toot like a pipe organ, lol.




Brad92 said:


> Does box shape have anything to do with how it will sound? If I put a port on the passenger side, will that shallow center section have any effect on the sound?


the shape of the box doesnt matter to an extent. obviously you wouldn't want a box that is 2" deep, even if you could get the volume you wanted, it wouldnt work well.

with a port, you need to have clearance at the mouth of the port at both sides. inside and outside. so for a 4" round port you want 4" of clearance outside the port and 4" of clearance on the inside of the box. for a square port, use some judgement. if the port is 2" x 10", then 2-3 inches of clearance should be ok.


----------



## Aaron'z 2.5RS/WRX

Wish I had seen this sooner....

I used to build some pretty amazing pre-fab truck boxes for Orion (SubZone early 90's) 

We had a single 10 truck box with a top firing square/slot port... 

I swear to god, that box impressed me every single day... a single ported 10 took place of 2 sealed 12's and seriously never let me down (and as a 20yr old, I beat the holy hell out of it)

I feel you might run into a bit of a boundry loading problem with the ports firing at the sides of the truck (depending on distance to the side wall of course) 

I doubt you'll have an issue, but if you DO and decide to rework the box, might consider top porting it..


----------



## Brad92

Ok, I can do a top port. Is there a certain calculator I should be using? I've been using this one:Car Audio - PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES


----------



## minbari

that one works, I dont know what the "is this a slot port" button is compensating for, but if you leave it off, it gets the same lengths as winISD does, so I would leave it off.


----------



## Aaron'z 2.5RS/WRX

Brad92 said:


> Ok, I can do a top port. Is there a certain calculator I should be using? I've been using this one:Car Audio - PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES


Just a suggestion, you do what you like... It's just porting up keeps restriction (if any) down... 

The port on the boxes we built, used the back wall/side wall and had an intenrnal baffle to create the port (front being angled) that came togehter, just below the top plate..


----------



## Brad92

I tore the box down and I have 15 inches inside height and a 2.25 in inside top depth with that notch. The calculator says I need 23 in port area but I can't get to that without exceeding 15 inches with the slot port setting unchecked. If it is checked, I get 13 inches..
.


----------



## Brad92

Aaron'z 2.5RS/WRX said:


> Just a suggestion, you do what you like... It's just porting up keeps restriction (if any) down...
> 
> The port on the boxes we built, used the back wall/side wall and had an intenrnal baffle to create the port (front being angled) that came togehter, just below the top plate..


I was thinking about using the middle section for the port so the sound would be more even through the cab. Maybe I'm just being crazy?


----------



## minbari

Brad92 said:


> I tore the box down and I have 15 inches inside height and a 2.25 in inside top depth with that notch. The calculator says I need 23 in port area but I can't get to that without exceeding 15 inches with the slot port setting unchecked. If it is checked, I get 13 inches..
> .


like I said, I dont know what they are compensating for with that checkbox. 23.75" is correct if it is a 4" x 4" tuned to 35hz with a 1.3cuft box. 10.2" long for 2.6cuft. the port doesnt have to be straight either. you can make a bend and turn it 90° to get more length.

try this one

Subwoofer Enclosure Calculators, Fraction to Decimal, Parallel, Series, Port Length and Volume Calculators




Brad92 said:


> I was thinking about using the middle section for the port so the sound would be more even through the cab. Maybe I'm just being crazy?


for sub-bass, you not likely hear a difference. it wont hurt it for sure.


----------



## Brad92

Thanks for the other calculator. 

I'm gonna need about 18" of port length...

Edit: Just reread the above post and it answered my question. 
My bad

How would I figure port length with a 90* bend?.


----------



## minbari

sure, you can bend it into a corkscrew as long as the port area and length are correct 

all kidding aside, bending it at 45° intervals works the best, it keeps the port area more consistent through the bend and helps the air make the bend with the least amount of disruption. to measure port length, measure it on center. (not from the sides)

just, however you do it. keep in mind that any amount of space the port takes up is subtracted from the box volume. you dont have to have all the port in the box either. if you need extra length you can put any amount of the port outside the box. (you also only need to subtract the volume of port INSIDE the box if you do this)


----------



## Brad92

Found my jigsaw! Bad news is that I lost all my blades, so I've gotta get some new ones.

And I'm going with a single port on the passenger side. Its about the only place that I have the room for. Thanks for all the help and steering me in the right direction. I'll get some pics up when I get it further along.


----------



## Brad92

Just about done. Got the holes for the subs cut out today and the changes done. Just have to attach the 2 front pieces, install the terminal cup and subs and I'm done with the box.

Quick question: where's the best place to get carpet? I checked Lowes, Hobby Lobby, Best Buy and a couple other places locally. I didn't check the local car audio shop as they're usually 1.5x more expensive as everywhere else.


----------



## airseeker

Best buy has some trunk liner but it's hard to use, when I need a big piece there is a local place here in Nashville called farbers apoulstry... Its wholesale and u need an account...


----------



## Brad92

I think I might go with this: Amazon.com: R/T Professional Speaker Box Carpet/Black-1 Linear Yard (36"x72"): Car Electronics


----------



## airseeker

That's the same size of the stuff you can get at bestbuy... 1 yard might not be enOugh for the size of your box... At least by the looks of pictures... Jus sayin, just swing by your local car audio shop, I bet you can get it for farly cheap cuz the have it by the roll I bet and will cut u some off for $20... Mine does at least and it's an 80" wide roll


----------



## Brad92

I'll stop by the local car audio place and see.

I finished the box minus the terminal which won't be here til tomorrow. I measured one last time for internal airspace and came up with 2.5^3 including port volume and sub displacement. I think its pretty good for a regular cab truck with decent legroom and a functioning center jump seat/console.


----------



## minbari

Have to let us know how it sounds.

Sent from my Motorola Electrify using Tapatalk 2


----------



## airseeker

I'm interested too, can't wait to see finished pics... Keep us posted! Hope u find reasonable carpet


----------



## Brad92

Thanks guys. I couldn't have done it without yall's help. Especially minbari. I appreciate you walking me through the porting. 

If it sounds anything like my old MTX 10, I'll be happy. I had so many compliments about how clean it sounded and was pretty loud.


----------



## dales

minbari said:


> no ,if you change the port area, it changes the port length. so if you went with a 4" x 10" port, you would have a single 28.5" length port.
> 
> for a pair of 10" subs with 500watts of power a 4" x 4" would give you about 118 ft/ sec port velocity, that is a little on the high side, but wouldnt be un-usable. if you changed it to 4" x 5", it would make the length 13" and port velocity to 94ft/sec. (ideally you want it less than 100 ft/sec)
> 
> where you put the port is not very important as long as you have proper clearance at the exit. you dont want the port sitting right up against the side of the cab.
> 
> 
> as for advantages, that is really it. if the box you have biult is large enough, there is no sense in rebuilding it. just remember that the port volume (LxWxD) needs to be subtracted from the gross box volume. so if you had 1.3 cuft of space and .2cuft of port volume and .1 cuft of speaker volume, you now have a 1cuft box


awesome informative post


----------



## Brad92

I'm kinda annoyed. I'm still waiting on my terminals. I ordered 20ft of speaker wire the same day and I got it 2 days ago. 

We'll see if it comes tomorrow, hopefully it does.


----------



## Aaron'z 2.5RS/WRX

Terminals.... 

Drill a hole, run wire, tie in knot, silicone inside of hole and knot (with about 3/4" wire in the box, between the knot), pull wire through, call it a day...


----------



## Brad92

I couldn't wait, I installed it earlier. I am very pleased with the sound, it sounds very clean and my subs hit low notes with ease compared to before. I now need to deaden the back wall of my cab even more thoughbecause of rattles. I'll get some pics up tomorrow.

Thank y'all so much for the help and bearing with all my stupid questions. I'm very happy.


----------



## Brad92




----------



## Aaron'z 2.5RS/WRX

Come on dude, finish your work...

Nothing like building a nice box and then not going the, not even extra mile and not finishing it up... 

Excitment is understandable, but when someone goes "oh, you got it running, lemme check it out" you gonna show'em that.. ? 

Some sanding.... some primer.... some sanding..... some paint... 1/2 a day at most... 

DAP lightweight finishing spackle does WONDERS over bondo at filling holes, super easy to work, no mixing (thought it should be mixed up) http://www.google.com/products/cata...a=X&ei=La2uT_7_B-mE6AGk39WTCQ&ved=0CG0Q8gIwAA#

Black "fleckstone" would look nice in that interior and it covers well.. 

Not doggin ya, but come on, show us you're proud of your nice work.. 

Looks great otherwise..


----------



## minbari

Looks good, glad it sounds good too.

And ya, once it is all finished, gonna look great

Sent from my Motorola Electrify using Tapatalk 2


----------



## Brad92

Aaron'z 2.5RS/WRX said:


> Come on dude, finish your work...
> 
> Nothing like building a nice box and then not going the, not even extra mile and not finishing it up...
> 
> Excitment is understandable, but when someone goes "oh, you got it running, lemme check it out" you gonna show'em that.. ?
> 
> Some sanding.... some primer.... some sanding..... some paint... 1/2 a day at most...
> 
> DAP lightweight finishing spackle does WONDERS over bondo at filling holes, super easy to work, no mixing (thought it should be mixed up) Dap 32 oz. Fast 'N Final Lightweight Spackling 12142#
> 
> Black "fleckstone" would look nice in that interior and it covers well..
> 
> Not doggin ya, but come on, show us you're proud of your nice work..
> 
> Looks great otherwise..


Ironically, you're the one who was saying to go without a terminal cup to get it installed....

But anyway, I'm going with black carpet. I liked how that MTX box looked with black carpet and I'm painting the inside of the port black. Should get it done within the next week or so depending on when I can get the carpet...


----------



## Aaron'z 2.5RS/WRX

Brad92 said:


> Ironically, you're the one who was saying to go without a terminal cup to get it installed....
> 
> But anyway, I'm going with black carpet. I liked how that MTX box looked with black carpet and I'm painting the inside of the port black. Should get it done within the next week or so depending on when I can get the carpet...


No actually, I said you don't need a terminal cup

The wire can go into the box anywhere, I'd have just put it up from the bottom so noone would see it anyway... 

You where just waiting for the cup... I gave you a way of not waiting for the cup and finishing the box, so you could get it in... :laugh:

You went a different direction... 

Sorry meng... wasn't trying to be a tool...


----------

