Complete Novice With Several Questions

[Umbra]

Hello, a few days ago I picked up two 12" subs, a box, and an amp from a local guy on Facebook for $30. They've definitely been used, but I believe everything to be in working order. Apart from the challenges stemming my very limited knowledge on the subject, I've also got two additional problems. Firstly, there's no identifying information on the amp. The fuse says 20 on it, that's about it. Here's a picture:

It's a link; it's too large to display inline

The other problem is the subs are mixed. They're both 12" and fit the box, but one is a Dual XNBP12D, 8 Ohms, 550w peaks, and the other is a JBL GT 1241D. The second one confounds me. I believe it's a DVC sub, though I'm not entirely sure what it means. It has four terminals and the label says "2 or 8 ohms" and "Recommended Amplifer Power: 18w-300w".

The box fits two 12" subs and is wired for one terminal.

I really don't want to push any envelopes, I just wanted to hook up the subs in my girlfriend's '02 Elantra because even if they're weak they've got to be a hell of a lot better than stock.

I was hoping some of you nice car gurus could advise me on the best way to set this up. I know there are different ways to wire them, I'm looking for reliability over power.

Thanks

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[jrdnhsnbrg 10+ year member]

Take a multimeter across the box terminals, it should measure somewhere around 4 ohms. Then get back to me and I/others can help you better.

 

[hispls 5,000+ posts]

Mix-matching subwoofers is a really bad idea. You will need an amplifier, some wiring, and probably a LOC (if you don't have aftermarket head unit) to power them anyway even if you just want to hook it up as-is and call it 'better than nothing'.

 

[jrdnhsnbrg 10+ year member]

Mix-matching subwoofers is a really bad idea. You will need an amplifier, some wiring, and probably a LOC (if you don't have aftermarket head unit) to power them anyway even if you just want to hook it up as-is and call it 'better than nothing'.

If they're the same impedance it shouldn't be too bad, should it?

 

[Umbra]

I'm not sure if I did it right. The box has this plastic item mounted in it. On the inside of the box unit, on this little plastic thing there are two metal prongs and on the outside of the box there are two of those clamps to connect speaker wire. I set the multimeter to ohms and stuck a prong in each, but it reads zero.

I purchased an amp install kit, so I've got power and speaker wires along with a fuse, fuse holder, connectors, ties, and some other goodies, and I've got a Dual brand aftermarket head unit I've never used that I plan to install if I can get this stuff working.

 

[hispls 5,000+ posts]

If they're the same impedance it shouldn't be too bad, should it?

Not that simple really, but at this point it probably doesn't matter. Expect really pathetic performance when you mix and match though.

I'm not sure if I did it right. The box has this plastic item mounted in it. On the inside of the box unit, on this little plastic thing there are two metal prongs and on the outside of the box there are two of those clamps to connect speaker wire. I set the multimeter to ohms and stuck a prong in each, but it reads zero.
I purchased an amp install kit, so I've got power and speaker wires along with a fuse, fuse holder, connectors, ties, and some other goodies, and I've got a Dual brand aftermarket head unit I've never used that I plan to install if I can get this stuff working.

0 ohm is a problem. Try this, plug your speaker wire into the terminals on the box and take a flashlight battery (like a AA or something) and tap the two sides of the speaker wire to the + and - sides of the battery and see what happens.

 

[Side Show 10+ year member]

use the jbl sub only IMO..... if it's not blown ect ect

 

[Umbra]

I've done some more research and now understand how DVC subs work and the different ways you can wire them. Now I have a new problem: one of the coils on the DVC sub is bad. The good (or relatively good) coil reads ~3.7ohms, the bad coil reads ~1ohm, that's why the series/parallel experiments were giving me completely unexpected numbers.

I briefly hooked up a 9V battery to the terminals to corroborate these results. The blow coil jumped about 1/4th of the distance of the better one, which worked out mathematically. The SVC sub reads ~6.5Ohms, but it's rated for 8, so I think it's beat up. This system has definitely been used, maybe even abused, but I think I might still be able to make it work. I hooked up each sub one at a time to a non-car amplifier and was able to get them both to work. Now I've got nothing to compare them to (and that's probably a good thing), but they sound decent and deliver a hell of a lot more base than the stock speakers.

I'm still perplexed by the box impedance. I figured out what I did wrong earlier, I tested the terminals without establishing a connection. I wired the two terminals and tested the opposite side and got results around .5ohms.

I still have no clue about the specs of the amp, the brand, anything. I would assume it was used in this setup at some point if the guy had it.

Assuming I wire all this up correctly and let's say something, the sub/s or the amp fails, what's the worst that can happen? The subs and amp die and the fuse keep the rest of the car safe? No, wait, the fuse it to keep the audio equipment safe from the car?

 

[Full Tilt 10+ year member]

I'm gonna be honest here, man - I think you paid $30 for a box (which honestly isn't even that bad if it's decent). Could we get pictures of that to see if it's somewhat usable?

 

[Umbra]

I'm gonna be honest here, man - I think you paid $30 for a box (which honestly isn't even that bad if it's decent). Could we get pictures of that to see if it's somewhat usable?

Sure, here's the box:

Box

And the subs, if anyone's interested:

Subs

I was wondering if it'd be possible to wire a resistor alongside the bad coil to at least make the thing electrically sound.

 

[Full Tilt 10+ year member]

Sure, here's the box:
Box

And the subs, if anyone's interested:

Subs

I was wondering if it'd be possible to wire a resistor alongside the bad coil to at least make the thing electrically sound.

I can't view those photos on this computer - I'll check them out on my personal one tomorrow. But from what it sounds like, your subs are either going to need some recones or replaced. Either way, make sure all of your subs are the same exact kinds.

 

[Side Show 10+ year member]

so are both subs bugger'd? show us your box ! lol those links don't work

 

[Umbra]

Sorry, guys, I thought I could hotlink them from Google's attachment servers, but I guess credentials are needed. Let me try again:

Amp

Box

Subs

 

[argenis69 10+ year member]

I guess for $30 dollars you didn't lose at all, because no matter how cheap the amp and box is, its worth more than $30.

 

[jrdnhsnbrg 10+ year member]

I guess the box isn't too bad, assuming the amp works you didn't lose any money. I'd ditch both subs and pick up some cheapos off craigslist. You really don't wanna use any sort of damaged sub, you risk hurting the amp and worst case scenario lighting your car on fire.