Old setup... Chevy Suburban. Pioneer f700bt headunit with sub out and some sub controls in the head unit. Sub RCAs out to a JL500/1 amp pushing a 12" ARC sub.

New... E60. No Logic7... normal radio. Same amp and sub. The signal for the amp is pulled from a LOC. The LOC attaches to the speaker wires coming out of the bottom of the factory amp in the drivers side wheel well location in the trunk. The LOC gain is turned down pretty low because of my problem below.

So this same amp and sub in the Suburban was amazing. Very clean and accurate through all volume levels. It hit clean and hard when loud... hard enough that it would darn near affect my vision (not that I did this often). The reason I liked the setup was because it was so clean no matter what I was listening to. In the E60 it sounds nothing like it did. At low volume it's "ok" but as soon as any real volume gets into it it starts to loose the clean sound and starts to sound like an underpowered speaker... not tight at all. I have double checked all amp settings, identical to where it was. The only difference is the headunit and LOC.

How is everybody wiring their amps around here? Do you run a LOC? If so, where to (specifically... to what location with what wires)? I have heard that it may not be required to run a LOC from the location that I'm tapped in to. Can I peel back RCA cables and splice them directly into those lines?

I am completely puzzled. We're not talking about a little different, it's gone from an amazingly clear clean bass to something boomy and unpleasant at any medium range volume. It's unlistenable at high volume, it sounds like I'm causing damage to the sub.

I haven't yet cut my ski pass open and will do that next Thursday... I'm taking the day off to wrap up some loose mods on the car and really would like directly on fixing this at the same time. Please help!!!

TIA, Andy

sup !.. no worries on the RCA's or LOC u dont really need them if u have ur amps wiring kit so u can tap into the speaker leads.. but yeah here are some links i used when i did my amp install..

check post #13
this one has good pictures to use as visuals :P

GL! :thumbsup:

Great references, thank you!!

So if no LOC is needed then how do I convert speaker wires into RCA cables? Doesn't an RCA cable have a + and -?

what he meant was a LOC is not needed IF your amp has high level inputs. it's a connector out of your amp using regular speaker wires meaning you elimate the RCA's. i am using a soundgate LOC-X convertor and it works outstanding. turn it up about 3/4. gain on amp about 40% and the crossover on the amp at 50hz.

i would first make sure your frequency on the amp is not set too high. then check your LOC. some of them have the ability to switch between a hz or full range. obviously you dont want full range. maybe this is your problem!

ive never did any installs on bmw's but ive done many installs in previous cars and, pardon my ignorance, but just by reading your post, I would suspect its the head unit. i dont know if other members have run it this way successfully, but i am guessing its the pre amp out puts for the stock head unit. the pioneer, im guessing, is at least 2v. the stocks prolly 1. just re set your gains. and work from there. your subs prolly sound underpowered because the gains arent set accordingly. on other installs i would just install line drivers or an eq that has a higher pre amp out, but i dont know if this is possible with the bmw system. hope this helps a little.

Maybe a dumb question to post here, in this really awesome DIY sound upgrade thread with all you really smart & skilled electronics experts (so it seems)... but:

Even though I'm not afraid of tinkering with my car, I'm plain scared reading through this thread and realizing how much it seems to take to install a better sound system. No way I can do this; sorry. I simply don't have the skills for this mod, I have to admit. However, I still need some more "oomph" in my 530 with stock HiFi system.

So... what to do?

Is there a plug & play replacement I can buy off the shelf? Something, that doesn't require me to know/find out where "to take voltage" from, "install an amp remote" or worry about "RCA and LOC" and all the other crazy stuff you good folks post about? It's all Greek to me... [..Dang!]

What I do know, though, is that I will not leave this upgrade job to my $tealership, as they will certainly f***k me over... (like they always do).

My question:
Would you happen to have any suggestions on how I can plug-and-play upgrade my stock sound system? I have no idea where to start, or what to upgrade (first) in this matter...

Just so you know, I am not looking for anything fancy. I just need higher volume levels since I'm almost entirely listening to music coming from my iPod (plugged into the rear console line-in) - and that doesn't get too loud with sunroof or windows open.

Any brands, links - or the likes - for a **simple** Amp (or whatever) swap/upgrade; suitable for the electronics-challenged 530i owner?

---Thanks, guys!

I don't mean to freak anybody out so don't let this steer you from tinkering. I'm paying super close attention to the sound quality here only because I knew how good it was in the old truck. If I didn't have that as a reference I'd probably just say it's better and be done with it.

What most folks are doing around here is two fold. First, if you are looking to improve your mid/high's many are swapping those speakers out with a different setup... BSW, whatever. In some cases that improvement is enough, others are looking for better volume and amping those speakers further.

The other side is bass, which should be straight forward. All of your wiring is in the trunk which makes it easy. If you are interested in a step by step how to there are several on the forum or I can shoot you a note. Without RCA cables you're stuck using a LOC, that attaches to the speaker wire under the current amp in the trunk.

I built a "false wall" in front of my amp/sub to improve the looks of the trunk without having to worry about anything hitting the sub or amp and causing trouble.
https://i687.photobucket.com/albums/...W/IMAG0260.jpg

To add another question to this thread... I'm curious where everybody is mounting their bass gain knobs at. I thought I could put it on the black plastic piece in the dash where I don't have a heated seat button. After tearing the dash apart to work down to that location I found that it wouldn't work. I finally mounted it on the "carpet strip" near my right knee so that if I ever want to remove it the carpet will "hide" the hole. It's a little lower than I hoped it would be but works and is reachable.

So you think gains go up? It occurs to me that I had the sub out "gain" on the old headunit turned down. In order to accomplish this here I thought about getting a crossover that I can put in line to the amp and then make some adjustments with 1) gains and 2) crossing over the frequency. The amp is a JL 500/1 and has a crossover, though. For $70:ish I figure it's worth the shot.

i did not install a bass knob. a properly tuned system will be fine. a bass knob will never hurt but i like the clean factory interior look. yes there are fine adjustments still but you don't want overpowering bass at low volumes and you don't want your frequency set too high that it sounds horrible which is the case in almost all systems i hear from other vehicles. this is why you tune the amps when the system is around 3/4 full volume.

back to your original concern if it hasn't been fixed yet...what brand/model LOC are you using?

The LOC is whatever brand (e2?) Fry's sells for about $20. There is no adjustment on it for full range / low pass. I'm taking a day off on Thursday to have the new wheels/tires put on the car and am planning to unmount the amp and play a little when I can see the settings a little better just to be sure that there isn't a dial that got set high on the frequency or something. It's not bad, it's just not yet perfect. :)