Shallow subs

[Dan-man18]

I'm making a box that is 20 H - 18 L and 8 inches in length at the bottom and 5 at the top for my truck, going to be putting a shallow amp in it that goes as far a 3 inches wanted to know if that would be good enough cubic feet for the sub its a 12 inch and maxes 1000 watts. The box is sealed!

 

[DaTT]

You'll need to look at the spec sheet for the sub manufacturer. They will tell you the volume required for the application you want. Every sub is designed different.

 

[phucheneh]

The Garage usually fields car audio stuff.

Obviously you're building around the free space you have. It can be hard in a single cab truck. I would be surprised if you could fit ANY normal 12" behind the seat. I've had 8" subs max out the depth I had available...that's with them mounted low in the box and and the face angled optimally.

Ditto 'look at the manufacturers recommendations.' You'll want to go sealed and polyfill will be a good idea.

Max wattage is a useless, fabricated number. If your sub has '1000w MAX!' written on it, it's probably crap and would be luckily to survive a couple hundred watts.

And if you need help on the math for calculating the volume of a wedge box...google it. Anyone can figure it out. What I always do is just look at it from the side and split that cross-section into a rectangle and a triangle. God help anyone that can't find the area of those. Then multiply that by the width of your box.

 

[Howard]

WinISD Pro, learn it.

http://www.linearteam.org/download/winisd-07x.exe is the version for Windows 7. The other version on the website works up to XP (and maybe Vista).

 

[mikeford]

Why use space in the box for the amp, put it someplace else with some air flow.

Something should fit and work with the volume of that box, doesn't seem odd for a truck box.

 

[Imported]

http://stereointegrity.com/index.php?id=47

Only requires .5 cubic feet.

 

[MixMasterTang]

Just get this and be done with it: http://www.crutchfield.com/p_136112...la&awnw=g&awcr=33877674265&awdv=c#details-tab

 

[phucheneh]

400 bucks for a shallow mount 12w3? No thanks.

I'm not familiar with 'Stereo Integrity,' but I'm guessing it's another upstart company selling their own designs direct to customers. Like RE, AA, and others...before they switched to selling to dealers only and the prices of their products doubled (or more).

Such companies usually offer some smokin' deals on very competently-designed drivers. Better built than JL's (less penny-pinching on simple stuff like cone and surround materials, for one) and you get more for the money (or 'same for less'). The linked SI sub is about the same as that JL in both displacement and power-handling.

I would only go to shallow subs as a last resort, though. If OP's max dimensions are right...assuming he's going off the outside and using 3/4" MDF...he should have 5-6" of mounting depth to play with.

Front face of box counts towards depth of sub, so that's 4.25" at the top of the box and 7.25" at the bottom. It 20" high, that means he can position his sub low, with the uppermost edge of the magnet coming in somewhere around or below the middle point between his 5" and 8" measurements- i.e. ~5.75" of depth, maybe more depending on the width of the motor and how much the angle of the box's face affects it.

I would pick this $79 sub over a JL w3.
http://www.woofersetc.com/p-8143-re...bwoofer-dual-4-ohm-oem-by-image-dynamics.aspx

It is the same thing as this, which is still a better deal than JL at $159.
http://www.woofersetc.com/p-4995-id12-v3-d4-image-dynamics-12-dual-4-ohm-v3-subwoofer.aspx

Mounting depth on an ID12 is 6". The other one is 5.75" because they omit a silly little plastic cover over the magnet. Cut the hole in your box at a point where the basket is pretty much butting up against the bottom of the box, and it should fit. Remember, you'd only need an actual 5" between the inner walls of your box, which is exactly what you would have at the halfway point between your 5" (3.5" inside) top and 8" (6.5") bottom.

 

[LikeLinus]

400 bucks for a shallow mount 12w3? No thanks.

I'm not familiar with 'Stereo Integrity,' but I'm going to talk out of my ass for a few paragraphs so it sounds like I know what I'm talking about.

Anyways, "for the sub its a 12 inch and maxes 1000 watts", sounds like he's saying he already has a sub? Do you already have a sub or need to purchase one?

 

[phucheneh]

Anyways, "for the sub its a 12 inch and maxes 1000 watts", sounds like he's saying he already has a sub? Do you already have a sub or need to purchase one?

Oh, sorry to give good, thorough advice to him on how to do a decent sub install for a decent price given what he has told us.

He told us the dimensions of the box and assumably he has some kind of cheap sub. I told him how to figure his box volume and recommended a sub that does well in small sealed boxes without breaking the bank (i.e. not JL) or being unavailable (SI, who I did not insult, but merely said I was not familiar with because I'm not up on the current small manufacturers).

But feel free to be all butthurt over nothing.