How do you know when you have a blown sub?

[95ExplorerLtd]

Hi everybody,

I'm going to help my cousin put a system in his Dakota, and I'm building the boxes for him. You can read the story on page 3 of my Sounddomain page, its linked in my signature. He wants two 10's, so me and my dad put together a sort of project box and made it as small as possible for a sub that I have. Once we had it all put together and all the screws in it, I put in the terminal, port, and sub and hooked it up in the Explorer. It sounded terrible! I hadnt yet sealed teh box so there were some small gaps, especially on one side, but it made a terrible windy sound and no bass. I sealed it up yesterday really good, and it made a big difference.

For anyone who doesnt know, the space behind the seat of the new Dakota's is VERY small. The sub is an old Kicker off-brand that I have talked about on here before. The mounting depth was like 4 3/4", and we used 5/8 board for the box. The back wall had to be ground out a little bit to fit the sub in there.

After the box was sealed up, I hooked the sub back up again and set it behind my back seat, and it sounded better than before it was sealed, but it still couldnt even compare to my MTX's I then went and put the box behind my drivers seat and laid the back seat down to simulate what his situation would be like, and it sounded really bad. It made a 'burr, burr' sound and not much bass came out of it. I'm starting to think that it's blown. I was just wondering if theres any way I could tell. Or is there just not enough air in the box? Whenever I open the port up I cant realyl hear a difference, but this is the first time I ever tried putting a port in a box, so I could very easily be doing something wrong.

Heres a couple more pictures of the box. The port is now finished and it doesnt stick up out of the top so far and looks much better.

The final measurements came out to be 18" wide, 13" tall, 6 3/4 deep at the bottom, and 2 7/8 at the top or something like that. Its a pretty crazy box, but it will hopefully work.

Grant

 

[leenjen]

that box looks like it's way too small to be ported. it might even be too small for that subwoofer in a sealed application. what is the length and diameter of the port?

also, what are the specs for the subwoofer?

fs-
Qts-
VAS-

 

[leenjen]

i just noticed you had the box dimensions at the bottom.
that box is WAAAAAY too small. you can seriously damage the subwoofer. the internal volume of the enclosure is only 0.36 cuft. and that's not including the displacement of the port and the subwoofer. you might have less than .25 cuft of airspace in there. that's enough to destroy most subs. and since it is ported, that is even worse.

 

[95ExplorerLtd]

Lee,

The port can be closed, would that make any difference? Also, what other options do we have if this box wont work? He really wants to have 10's

 

[leenjen]

that enclosure is too small, even if you do make it sealed. see if there's any way you can make a larger enclosure. try to make it wider (and deeper if you can).

what are the subwoofer specs? (fs, Qts, VAS)

 

[95ExplorerLtd]

The sub is too old to find specs. Pretty sure anyway, its like 10 years old or in that area. It used to be a smaller division of Kicker, called 'Blues'. Even if I could find the specs, I dont know what fs, Qts, and VAS mean I had an idea though. He will have to settle for two 8's instead of two 10's though. I'd hate to just scrap this box (since I put carpet on it), so I was thinking make a plate that will fit over the hole for the 10, and cut a hole in it for an 8. That way a halfway decent 8 should be able to fit pretty easy and should have a reasonable amount of airspace. Am I going in the right way now or am I still totally off? If this will work, what can I use for the plate? Something thin that will support the sub, but I dont know what all I can use. Thanks for all the advice Lee.


Grant

 

[95ExplorerLtd]

Well, I did some reconsidering, and the plate idea sounds like a bad one now. Spring Break starts at the end of this week, and we will be going to my grandparents, and he keeps his truck at my uncles, just through the woods. I'll run over there and stick the box in and see how much wider and taller I can go. It wont be able to go any farther out though. If it wont be able to somewhat comfortably fit a 10, its going to have to be 8's. The only way I'll consider a 10 is if I can increase teh width and height by a few inches each way, and it will be sealed. I'll be using a new sub, same brand and model, but just one in better shape, if a 10 can be used.

I put carpet on the project box, since it was the first time I had ever carpeted a box, and I didnt htink it turned out all that bad for a first time effort. I think it all looks pretty sharp. I may post pics of it sometime later.

 

[leenjen]

all subwoofers are different. some are designed to work in small sealed enclosures (but i never heard of a 10" sub that can fit in something that small). why not make the enclosure go the width of the cab? build it from one side to the other.

 

[95ExplorerLtd]

The center console and armrest goes all the way back to the wall, so going all the way across wont work. We'll be going down in a few days, so then I can see how much wider and taller I can make it.

PS- I got a different sub (same brand and model, just a different sub) and put it in the box and it sounded waaaaaaaay better, the difference was night and day.

Here is a picture of the finished product. I thought the carpet turned out really good, being the first time I ever carpeted a box. I also got a couple grilles, and everything turned out very nice. I was very happy with how the box turned out.