Hi,

For almost three years, I've had the same audio setup in my Cobalt. I have an Alpine CDA-9886 head unit, alpine speakers, and Alpine MRP-M500 mono amplifier, and an Alpine Type R 1243D subwoofer in a sealed box. Last week, my sub blew, so I bought another brand new Alpine Type R 1243D sub (same one as my old sub).

So first things first. I removed my sub box from my car, removed the blown sub (I know it blew because it stopped working while driving one day, and I tested it with an multimeter and it scratches when I press on the woofer cone, so voice coil is fried), and put the new one in. I wired the new sub correctly for two ohms impedance, and ensured secure connections at the correct terminals with the jumper wires and the sub box wires. I secured the new sub in the sub box and assumed that once I hook up the sub box to the wires from the amp, that it would work. However, this hasn't been the case.

My setup functioned for years until my old subwoofer blew. I haven't messed with any cables anywhere in my system since changing the sub. I can assure you the following as well:

1.) My head unit is set to Power IC ON, Subwoofer ON and I've tried Subwoofer setup 1 and 2 to no avail.
2.) I've restarted my head unit several times.
3.) The RCA cables from the subwoofer outs on the head unit are installed securely and correctly.
4.) The remote wire is correctly hooked to the amp because it turns on when I turn my car key to accessory or ignition.
5.) The blue light on my amp turns on
6.) The ground for my amp is 1 foot long and on a good ground with bare metal.
7.) THe power wire to my battery from my amp is securely fasted.
8.) I've removed my sub from the box to check everything and everything is hooked up correctly.
9.) The new subwoofer is functional because I tested it with a 9V battery wired to the sub box terminals and the subwoofer pops and moves (indicating it is functional).
10.) I've checked my amp settings and everything looks good. Also, all connections to the amp are secure and correct.
11.) My bass and subwoofer settings on my head unit are on and turned to a level where the sub would work.


Essentially, my old sub which worked for years on this setup blew. So I removed my sub box, and took out the blown sub and replaced it with an identical new one wired just as the old one was. But it's not working when music is being played. If anyone can help me with this, it'd be greatly appreciated. Any advice or input would be so damn greatly appreciated, I can't stand to not have a sub.

THANKS FOR LOOKING, MUCH APPRECIATION TO THOSE WHO HELP

 

Are you 100% sure the polarity on the voice coils is right? If it's a dual 4 ohm and you wired it for 2 ohm (in parallel) and reversed the polarity of one of the coils you'll get no output from the sub.

Failing that when you blew your voice coils and they shorted out it might have damaged your amp! Take a multi meter and put it on AC mode and disconnect your speakers from the amp, connect the multi meter to the speaker terminals and crank up the gain and head unit volume, do you get any voltage from the amp?

When you get it working make sure you break in your new sub properly!!!

Good luck.

-Jamie M.

 

yup id guess blown amp

 

The blue light on the amp turns on when the car turns on though. According to the subwoofer manual, this indicates the amp is good. Idk, this is pissing the **** out of me. I'm gonna go test it with the multimeter later

 

It's possible the amp is still powering on, but the output is messed up.

Easiest way to tell is like above. Remove The + and the - from the amp and just plug a multimeter in and turn the volume up. If the amp is popped, you will notice.

 

no that idicates the amp is on. theres a whole slew of problems that it could have and still show that light as normal

 

Ok so here's the update. I tested everything yesterday morning with the multimeter and everything checked in okay. I hooked everything up as if i had a working system and headed back to college after thanksgiving break. About half an hour into the trip, the sub suddenly starts playing, and has ever since. When that happened, I immediately took the first exit to turn down the gains and bass boost and play it at a low bass level and volume to break it in for a little bit.

If you knew what the problem was, I'd sure like to know. Beats me. I do think however, that my amp was in a type of protect mode because the light was quite dim (but was never blinking) when the sub didn't play. Ever since it's been working, the light has been fully bright. I don't know, I'd sure like to know what it was though. I didn't change a damn thing and randomly started working after a week of trying figuring it out.

 

hmm check power connections and fuse?

 

If it cuts out again it might be the patch cable. I had one break on me and the speaker would cut out every now and then (4ch amp).