So I've been trying to install a 12" MTX Sub and 400w amp in the trunk, and I have encountered a problem. I've read the DIY on this site thouroughy and still can't find a solution. I have the power, ground and remote turn-on all run perfectly, and the amp receives power when it is supposed to. I have the LOC hooked up to the HU rear outputs (not the amp to speaker outputs), and the LOC running RCAs to the MTX amp. The amp is then running bridged into the 12".

So, the amp is getting power, but the only way I hear anything from the sub is with the gain all the way up on the amp and the LOC. With the gain on the LOC turned up too high, I just blow my fuse. The sub, with the gain all the way up, only gives weak, muffled farts. I had this setup in my last car, and it thumped like a champ, but I'm sure that I've done something wrong here...

My sub has speaker level inputs, should I bypass the LOC? Should I have hooked up the LOC to the "Out to Speaker" on the Bose instead? Should I check my polarity on the LOC? I just don't know, any help would be greatly appreciated. I've got sunburn all over from being outside all yesterday, and the sub doesn't even work now!

Thanks in advance, I know this might be a redundant post, but I'm lost....

 

What about the gain from the HU? It sounds like your master volume is low (not trying to insult you - just worth double checking).

Other obvious thing to check: did you tap into the wrong wires? You by chance don't have a boom box with RCA inputs do you? You could use that to test the signal coming out...

Which fuse do you blow? Your amp or sub has speaker level inputs? I'm guessing you meant your amp... You could try those inputs and bypass the LOC as you suggested. Many have found that using the signal on the other side of the AMP (out to speaker) provides less noise. Perhaps because the LOC only needs to trim down the signal (not amplify).

Good luck...

 

Try switching how your speaker wire is connected to the sub, red to black or vice versa....

 

Thanks for the help, to answer your questions: I blew the inline fuse on the way to the amp...Also, I have speaker level inputs on the amp, along with RCAs. Right now, I'm running the LOC into the amp via RCAs.

My next step will be to remove the LOC and run a straight shot from the bose amp into my sub amp via the speaker level inputs. What you said about the LOC being better placed after the Bose amp, I'm not really getting extra noise, I'm getting crappy noise. Any way, I'll try to figure this out, it can't be hard.....Can it?

Oh, I had my main volume up thank you very much smarty-pants....

 

i think what is happening its that your not getting enough juice from the headunit for the LOC's thats why many install diaghrams say to run the LOC's after the Bose AMP.

 

Oh great. I'll try that, but the prospect of splicing is not enticing. Thanks. I'll tryi it out.

 

I have a 600 watt Diamond audio amp running to a ported Alpine R 10. It pounds way too hard for this car.

Anyway, no LOC needed. I spliced two RCA wires into the rear outputs (Pre Bose) and ran them straight into my amp. The amp has a good built-in crossover so make sure yours does too. Make sure you have good speaker wire to the sub itself. If your amp doesn't have a remote gain control, I'd recommend one (They make aftermarket ones that connect via RCA inputs on the amp). I have one that came with my amp and I mounted it just under the dash with black velcro by my right knee. Great to turn the gain down without changing the bass/mid range from the bose deck.

Good luck.

 

are you not getting any noise? i get a really mild whine. i'm still trying to debug it... but i think my grounds may be too long and that might be the problem. but i did the same thing. i spliced my RCAs to the prebose amp wires. and into my amps.

 

Whyjay- I like the idea of splicing straight into the pre-Bose input better than re-running into the LOC. Can the amp take speaker level input throught he RCA inputs? I guess it can because yours is working that way, I'm just wondering how that works. Also, my amp has no external gain control, where could I get one?

 

The output from the Bose HU going into the AMP is only 2.2V at max volume (per another thread where a member used an oscilloscope to measure it). Most amps can take this as line level input. A loc may not be necessary. Just set your HU to minimum volume, plug it in to your amp, and gradually increase the volume. I must admit I haven't done this myself. I use an AOEM-NIS2 which provides RCA outputs at the back of the HU, which I ran back to the trunk. This was specifically to avoid splicing into the stock wiring (so that returning to stock would be a cinch).

 

Sorry I'm so freaking slow to respond.

FrizzleFry - I get no noise. I am somewhat of a mobile audio/video junkie (have been for many years since working as an installer) and can tell if sound is even slightly off. I'm getting just clean sound. I use some splicers that I picked up from radio shack. Can't describe them too well but they are easy to pull off to return to stock in the future (which is why I went this route). They are a clamshell design where you'll place the RCA wire into the clam along with the proper bose (preamp) wire in parrallel, and finally clamping it down with some pliers. Easy as pie and can be pulled off even easier without retaping or reattaching wires. Not sure why you're getting noise or how you're splicing in. Maybe insulate your splices with some electrical tape? And, of course, make sure you're using a decent grade RCA wire(s).

Ravegoo35 - Most amps can handle the input. Just get a decent one. Heck, a $150 Alpine mono sub amp can take care of it for you. Since I'm splicing prior to the Bose Amp, the head unit is 'talking' (rather quietly) to the amp directly. The amp will take that signal and boost it to the sub. Keep the crossover low (below 70) and turn the gain up. You'll be set. I'm pushing nearly all of my wattage to the single 10" and it sounds soooo good. ; ) As to the remote gain, you can pick one up at any local stereo shop. Both Car Toys (not recommended) and Magnolia Hi Fi (recommended) carried them in my area. Just mount it under the dash, in reach of course, and run the wires back along the door sill trim and into your amps spare RCA ports. It will impede your gain and release it when you want from the cabin. If you don't have spare RCA's you may be able to split off the ones you're pushing into the amp from the headunit. Your local shop should be able to tell you how to set it up but that's what I remember. Mine comes with a built-in remote gain so I didn't have to worry about that.

Good luck guys. And when you're thumpin', pull the sunroof visor forward just a hair to get rid of the upcoming rattle.