[tmo24]

Ok I have done massive research here for the last 2 weeks and finally did my install today. Long story but I have a 2010 e90 with base audio and idrive. No amp. Just 4 speakers and the base 6.5 subs. I had access to 2 logic 7 subs from another e90 and an older Fosgate 500.2 amp sitting around. I thought it would be nice to run the amp to the logic 7 subs just to get more bass. This is now my girlfriend's car, but used to be mine. I would have gone a different route but she said she likes the way it sounds but just wants more bass. That's it.

So upon researching I found out the the subs have 4 wires. 2 that plug into the sub then 2 run back out to the front speakers, all powered from the head unit. The logic 7 subs have the same plug but just 2 wires for positive and negative. I know that the base audio subs basically provide a jumper to the fronts. So if course if I were just to plug in the logic 7 subs, not only would the front not work, but I would have full range coming just from the subs. So all this being said, I figured that what I have to do is to provide a jumper from the subs to the fronts or just tie them together, essentially completing the circuit. It's basically now just running signal from the head unit to the front speakers if I bypass the sub and twist the 2 positives together and then do the same for negatives. At least that's what's makes sense to me. Then I also ran the line output converter to my amp (only because I lost the high level input connector somewhere) and then ran speaker wires back to the logic 7 subs. I turned everything on at low volume and turned the gains all the way down. Then turned up the volume to a moderate level and turned the gains up slightly to see if the subs worked. They did. Everything sounded ok at low volume. When I turned it up, the bass stopped and all that would play is the left speakers. No subs. No front right.

So I'm guessing one of a couple things happened. I have to go check tomorrow since it's dark tonight. But something is wrong and I don't know if these are all of the variable or if I just completely missed the mark with how I thought I should wire this

BUT either:
1- Something is pinched on the right side
2- one of the wires is loose or possibly frayed and touching something
3- my ground is weak, even though I scraped down to bare metal and mounted to the body in the trunk but I'll recheck
4- my gains are way off but they are relatively low on everything

Whatever is happening, the head unit doesn't like it and the right channel turns off until I shut off the car and let it sit for a bit. Everything plays Fine at low volume but when I turn it up to try to tune things, it's clips and then the right channel and subs go out again. I wired the subs directly into each channel. I did not bridge the amp or run parallel of series etc. I do not want to over power the subs even though I have read that they can handle 150 watts rms.

Either way, I'm hoping to get some ideas on what to check. If I completely missed the Mark, please let me know so I'm not chasing down a potential wiring issue or a bad LOC etc when in all reality, I can't wire the system that way. The only other thought is that if I remove the 6.5" base audio subs out of the equation completely, that changes the impedance, so maybe that is why the head unit doesn't like it. I'm not entirely sure at this point.

In theory, this is similar to swapping the base subs to SWS subs and adding an amp.

[ctuna]

If the amp has high level inputs you shouldn't have to use a Loc.
As long as it has high impedance inputs.

Jumper the connect that goes into the underseats to the Head Unit
fronts only supply the doors.
T tap and run the same wires to the amp and then to your L7's
If that amp has some kind eq you will need to low pass.
Still that will be a ghetto system.

[tmo24]

Originally Posted by ctuna

If the amp has high level inputs you shouldn't have to use a Loc.
As long as it has high impedance inputs.

Jumper the connect that goes into the underseats to the Head Unit
fronts only supply the doors.
T tap and run the same wires to the amp and then to your L7's
If that amp has some kind eq you will need to low pass.
Still that will be a ghetto system.

Definitely ghetto and I knew this going in. I wanted to swap everything and use the JL 600/6, dsp, separates etc but she thinks crisp highs are just tinny. She somehow loves how the base audio system sounds and just wants more bass, so I figured this would be a low cost solution.

I ordered the missing high level input harness for my amp. I'll just use that instead of the LOC. I basically ran it the way you said so I'm guessing something somewhere is loose/pinched when I put the car back together or the old LOC I had laying around might be bad.

I appreciate the feedback even though I know this has been covered a billion times. I basically wanted confirmation that I was going down the right track instead of pulling a bone head move and wiring something very wrong.

So basically, the head unit now is running just the fronts and my amp is running just the subs. I'll check all connections and play with gains tomorrow just in case. If the problem still persists, then I'll wire directly to the high level inputs on the amp and go from there. I'm halfway hoping this doesn't work so I can have a reason to just do what I want to the system for her lol.

[ptpending]

i can ship plug and play kit which resolve your problem

[tmo24]

I got it all figured out guys. The smallest single strand of wire on the high level inputs to the LOC was frayed and barely touching the speaker connection next to it. Everything works and sounds shitty. Just a little less shitty than the base audio system because it has a little bit more bass and low end. But my fiancé will like it. Mine is getting a JL 12w6 in the trunk and I'm undecided on what to do with the interior speakers so far. I have logic 7. Cheers and thanks for everyone's input.