Custom Box for Truck; Size constraints - Help & Tips needed

[Memnoch]

Hello, this is my first post here! I am trying to build a sub box for my sons truck. It is his first truck, and we got him his first sound system for Christmas. There is of course size restraints on the box dimensions and I just want to get some feedback before I start cutting anything to build his box. The previous owner had some sort of subs installed, and the wiring is all still intact. The line to the battery is there, the ground is there, and the connections and remote line for the amp are all ran and connected to the deck already. I did purchase a wiring kit though in case but it doesn't look like I will need any of it except for the speaker wire to wire the subs themselves to the amp.

The 2 sealed boxes that the audio place sold us cut out the holes too big, and we won't be able to return them for a while (time and distance from us). So I purchased an 8x4 MDF sheet and the screws, glue etc.. to put one together myself. He would prefer a single box to 2 boxes if that is possible. Details are in the list below for the vehicle and subs etc.

Vehicle : 2001 Dodge Ram 2500

Location in the vehicle: Behind the seats

Space available (Length x Width x Height): 63 1/2" L 8 3/4" W 30" H

Subwoofer make and model: Massive UFO 12" shallow sub

Subwoofer Size: 12

Number of Subwoofers: 2

Type of Port (Kerfed, Slot, Aero, etc.): (unsure)

What type of music do you like?: He listens to pretty much everything but probably heavier on rap

Is your goal SPL or Everyday Music?: Everyday

Tuning Freq (Hz): Unsure

Volume : Unsure

Questions:

Recommended air volume is 1 Cubic Ft per sealed box per 12" sub. The only other recommendation I can find on the spec sheets for the sub is a dual ported box which is 3.11 cubic feet. But the dimensions of that box will not fit his space due to the limited depth of 8.75".

I have come up with a simple rectangle design for the box as follows:

34" long
18" tall
8.75" wide

with the .08 displacement of each sub that would give me roughly 3.13 cubic feet of air space, which is pretty close to the ported recommendations but there is no port on this. Would I add a port or would I need to adjust the dimensions of the box to reduce the air space? Should I add braces inside the box (which would further reduce the cubic space); if so would the dimensions need to be adjusted further?

Would it be better to seal in each sub on the box (ie adding a wall for each sub or a wall between them)?


Please let me know if I am missing anything or if there are any questions. Any help is greatly appreciated!

Click to read more...

 

[Memnoch]

This would be dual ported chambers



This is not

Ok tell me what you think...Also, brother in law came back and we screwed together the box he made...will need some sanding to take down the edges. I remeasured inside and it's actually a lot closer than I had originally thought. It's about 1.28 cu ft for each compartment. But man is it ugly lol...hopefully it performs well enough. My son has already asked me to build this box anyway, so he can see which sounds better for him, and I can just sell whichever one he doesn't want to one of his friends I am sure...throw some carpet over them and it will be fine enough.

One downside to this design though, I'll need 2 pieces instead of one due to the larger wider end cut.

 

[Doxquzme Premium Member]

Not this,

This.

This is the shape, 3.12 to 3.25 cubic feet. Port is 4.5 x 6 x 15.75 to 16 for the port size. Adding the extra L shaped at the end would drastically alter, almost double the port area and lower the tuning frequency to the low 20's, way to low. This worked out fairly well and should do the trick just as is.

 

[Memnoch]

Not this,




This.




This is the shape, 3.12 to 3.25 cubic feet. Port is 4.5 x 6 x 15.75 to 16 for the port size. Adding the extra L shaped at the end would drastically alter, almost double the port area and lower the tuning frequency to the low 20's, way to low. This worked out fairly well and should do the trick just as is.

Ok, I just saw that design you posted with the ported box and it had the flare/L shape at the end so tossed it in there lol...



Just curious, how much air space would 4 10's need, and what kind of power draw from an amp? What would the difference be sound wise with 4 10's vs 2 12's? I ask because my son and I were talking and he wants to put his own money in at some point and upgrade his amp/speakers to better pieces. If so, I could keep this design, fit 4 10's evenly spaced and increase the height to accommodate, which would get me around 4.50 or so cubic feet, and could adjust accordingly.

I think tomorrow we should have the brother in laws box done enough to wire speakers and amp and see how it sounds. If he doesn't like it, we are going this weekend to put this one together instead. If it is good enough, I am going to save this for the potential 4 10's version down the road.

Here's the 4x8 ft of mdf with the cuts laid out on it (threw the 4 10's on top just to see visually); sadly will need an entire new board just for 1 cut for the bottom of the box

 

[Doxquzme Premium Member]

Ok, I just saw that design you posted with the ported box and it had the flare/L shape at the end so tossed it in there lol...



Just curious, how much air space would 4 10's need, and what kind of power draw from an amp? What would the difference be sound wise with 4 10's vs 2 12's? I ask because my son and I were talking and he wants to put his own money in at some point and upgrade his amp/speakers to better pieces. If so, I could keep this design, fit 4 10's evenly spaced and increase the height to accommodate, which would get me around 4.50 or so cubic feet, and could adjust accordingly.

I think tomorrow we should have the brother in laws box done enough to wire speakers and amp and see how it sounds. If he doesn't like it, we are going this weekend to put this one together instead. If it is good enough, I am going to save this for the potential 4 10's version down the road.


View attachment 55932



Here's the 4x8 ft of mdf with the cuts laid out on it (threw the 4 10's on top just to see visually); sadly will need an entire new board just for 1 cut for the bottom of the box

Always check at the hardware store, they likely carry or may have a half sheet available, always good to ask.

As for four 10's, or upgraded 12s or 15's. Four 10s give you aprx 314 sq inches of cone area, two 12s, 226 sq in and two 15s give you 353 sq inches, roughly. A similar ported box for four of those shallow mount 10s would need about a 4.75 cubic foot box, sealed 3.08 (stuffed with 3 lbs of acusta-stuff or long fiber wool) and that box would work, sealed for four 10's. 15s are going to be impractical in that truck.

Multiple drivers will take more power, something you may want with the current configuration too. Sealed boxes are a bit quieter than ported ones too.

I would start with amplification first, then when you have a more powerful amplifier, a change in the speakers would be advantageous. There are some really nice shallows that would work in that box too. 4 of these 11" Si's would work in a sealed/stuffed, heavily braced 2.4 cu ft box and be able to handle 2000 watts of power, enough to interrupt your heartbeat! You will also pay to play with the likes of SI shallows. JL makes some nice shallows too. Several companies do.

BM-11 – StereoIntegrity.com

stereointegrity.com

There are lots of options when he's ready. Get these in and see how that goes, amplifier should be next on the agenda!

 

[Doxquzme Premium Member]

Meant to add, that all things equal, the power is split equally among any array of same type woofers, so a 600 watt amplifier will give 150x4 to the quad 10" setup (300 x 2 to a dual setup, etc) the difference would be the increase in cone area and that would be marginally better. Really no sense in doing that unless you move up to a beefier amplifier. Right now I'm running dual 13" Focal 33v2s in a sealed 3.44 cubic foot sealed and stuffed (3.5 lbs of Acousta-stuf) box. With cabin gain and stuffing, i'm measuring in the low 30s, pretty excellent for sealed. They are running at a 4 ohm load from a DS18 Hooligan H-KO3, gains turned down quite a bit so everything is running nice and cool and they are truly stunning in their speed, accuracy, punch and attack, really impressive!

I would highly recommend stuffing that sealed box with 2.5 pounds of Acousta-stuf, it really helps the smooth out the sound quality output.

Home

Acousta-Stuf Polyfill 1 lb. Bag Speaker Cabinet Sound Damping MaterialAcousta-Stuf, a synthetic material made from crimped fibers, is an excellent choice for filling or stuffing small enclosures or transmission line cabinets. Long fiber wool has been a favorite among serious speaker builders but...

www.parts-express.com

AND, no, nothing is needed in the ported box.

 

[Memnoch]

Meant to add, that all things equal, the power is split equally among any array of same type woofers, so a 600 watt amplifier will give 150x4 to the quad 10" setup (300 x 2 to a dual setup, etc) the difference would be the increase in cone area and that would be marginally better. Really no sense in doing that unless you move up to a beefier amplifier. Right now I'm running dual 13" Focal 33v2s in a sealed 3.44 cubic foot sealed and stuffed (3.5 lbs of Acousta-stuf) box. With cabin gain and stuffing, i'm measuring in the low 30s, pretty excellent for sealed. They are running at a 4 ohm load from a DS18 Hooligan H-KO3, gains turned down quite a bit so everything is running nice and cool and they are truly stunning in their speed, accuracy, punch and attack, really impressive!

I would highly recommend stuffing that sealed box with 2.5 pounds of Acousta-stuf, it really helps the smooth out the sound quality output.

Home

Acousta-Stuf Polyfill 1 lb. Bag Speaker Cabinet Sound Damping MaterialAcousta-Stuf, a synthetic material made from crimped fibers, is an excellent choice for filling or stuffing small enclosures or transmission line cabinets. Long fiber wool has been a favorite among serious speaker builders but...

www.parts-express.com

AND, no, nothing is needed in the ported box.

thanks for all of your help. I will report back tomorrow how it sounds. And I will be looking to replace the amp as soon as we are able to. I kind of hope he doesn't like it, I want to build that box lol...I know he doesn't like how it looks at all but money is money...

 

[Doxquzme Premium Member]

It will probably sound fine, it's just going to sound different than a ported box. If you can't get that Acousta-stuf, at least stuff it, I means stuff it full of about 2.5 lbs of polyfil, it makes an audible difference. I'm a fan of sealed setups, but the 13s that I use are specifically designed for larger sealed enclosers so that the low end is not compromised. Those 12's are not going to play very low in a sealed box, around 45hz so it may be kind of boomy. Some like that, just not my cup of tea.

 

[Memnoch]

It will probably sound fine, it's just going to sound different than a ported box. If you can't get that Acousta-stuf, at least stuff it, I means stuff it full of about 2.5 lbs of polyfil, it makes an audible difference. I'm a fan of sealed setups, but the 13s that I use are specifically designed for larger sealed enclosers so that the low end is not compromised. Those 12's are not going to play very low in a sealed box, around 45hz so it may be kind of boomy. Some like that, just not my cup of tea.

Ok thanks for the tip. So I just stuff it full? 1.25 lbs per side or 2.5 per side, it won't burn up? lol

 

[Doxquzme Premium Member]

1.25 er side, it'll seem like a lot, but it's fine.

 

[Memnoch]

minor update...got everything wired and installed. Got told that you and anyone else I sought advice from was an idiot when it came to running the speakers in parallel. Found out sons rear speakers were blown, so replaced them and the front ones too. It sounded like crap tbh at first with the old speakers in, but once I installed the new front/rear it improved it quite a bit. He likes the sound of the subs, but agreed that they don't seem to hit that hard or deep, and wants me to build the other box lol...so in a couple of weeks we are going to get the mats and build the new box, he wants to hear how it sounds. I think we are going to try and get a new amp if money allows. We will see.

He told my son when I had to run to my office for a little bit that "I know your dad wants to think he can do it, but hours of research and talking to people on the internet don't beat experience" lol

 

[Doxquzme Premium Member]

Hey, well, I guess those of us here and my 30+ years alone and the hundreds of combined years of experiences and their contributions are all made up or something.. That is funny, and maybe he's just picked up a little humble pie himself.

People on here love to share what they have learned. The best contributions are from those that don't pretend they know it all. If I have stopped learning, it's only because I must have stopped listening to other points of views. I think most of the info you get here is pretty "sound", no pun intended.

 

[Memnoch]

Hey, well, I guess those of us here and my 30+ years alone and the hundreds of combined years of experiences and their contributions are all made up or something.. That is funny, and maybe he's just picked up a little humble pie himself.

People on here love to share what they have learned. The best contributions are from those that don't pretend they know it all. If I have stopped learning, it's only because I must have stopped listening to other points of views. I think most of the info you get here is pretty "sound", no pun intended.

Absolutely. I am always learning and think it's probably impossible to stop learning. I appreciate the advice and don't doubt for a second the community here or your abilities. I look forward to building my own box and learning regardless if it is better or worse. It's fun to spend time with my son and learn