So I have the Bose "Premium" (if they call that premium, I'd love to see the stock system) audio system in my new X, and here's my plan to upgrade:

Keep Stock HU
Use LOC's to feed Alpine F450 5 Channel Amp
Boston Z6's in the front doors
Boston Pros for rear fill
Boston 10" Competitor Sub (in Boston enclosure)

Anybody see any potential issues? We're planning on mounting the Xovers for the Z6's (they are like a small amp in size) underneath the rear deck...

Should sound great- I'll post my thoughts after I have it done.

 

First off, I'm curious which LOC's are being used.

There are some LOC's which are intended to convert a balanced signal to single-ended preamp (what an RCA carries).

But I don't think that the Nissan Bose system uses a balanced signal. I think it's a single-ended signal (I DO think that the Delco Bose GM systems use balanced differential, but I'm not convinced that the Nissan Bose systems do).

An LOC might actually degrade the signal, if it's good enough the way it is.

So which LOC are you planning on using?

Secondly, it sounds like a good workmanlike system. Too much rear fill for good imaging - rear speakers are a commie plot - but a good workmanlike system.

I haven't critically listened to the Zs in a car. I found the old Pro's a bit dull and lifeless, though - but not strident or bright, more a sin of omission than commission.

What else have you listened to?

 

I purchased the David Navone NE-74V LOC for my system. I haven't done my install yet so I haven't tested it but it was highly recommended.

 

It works well on the high-level outputs of an amp. Soundgate sells a 2-channel version of that one as the LOCHVA, I believe.

I wouldn't use it on the low-level outputs of a head unit, though. It's meant for speaker-level signals.

I suspect the LOC you need might be a pair of one-male-to-two-female RCA "Y" adapters with the male ends circumcised, inserted on the HU preamp output... but hey, what do I know...

 

The LOC really isnt needed. You can simply splice the low levels coming from the back of the HU or any spot you choose prior to the amp. This has worked successfully for me and my customers for many years.

 

Well, the install was done this weekend. I substituted Boston 5.25 Coaxials for the Pros in the rear to make for better imaging. The system sounds really good (plays really loud and really clean), but I sure do miss the subwoofer volume control I had in my old car via my Alpine Headunit. I also have a slight alternator whine out of the left front speaker that they will be attempting to fix.

They ended up getting the signal directly off of the Headunit itself (before the stock amp). They also applied dynamat to all doors and the trunk.

Anyone with recommendations on processors or EQ's? I miss my Alpine Headunit (with it's EQ and Subwoofer control), but I want to keep the stock HU on the G if at all possible...

I also had a Escort ZR3 Laser Shifter installed

 

If you ONLY have engine noise on one F speaker, your passive xover for that speaker is probably picking up noise.

Does this noise remain without the HU on? THat would clinch it...

 

What are you trying to fix?

If you just want sub control, doesn't the F450 give you that option? It has a dedicated Ch 5 input... so you could have a sub level **** if they wanted to install one.

 

Yes- noise is persistent even with radio off- gets louder with increased RPM's. Is there something I can do to troubleshoot this? He mounted the xovers right next to the amp, and the capacitor is also near all of this (the xovers are in the middle). There are power and speaker lines that are touching/very close to each other. Could this be the problem?

Thanks

 

Doesn't need much troubleshooting.

Verify that with the key in ACC and the HU off the amp is off too. (It might not be because the installer may have used the stupid signal sense turn on in the LC6 and used its output to turn on the amp. This is why you don't use that stupid output : )

If so, you're done, it's caused by the location of the passive crossover for the speaker involved. Most wires near each other for a few inches are not a problem, and are also unavoidable. But if the amp power wire goes right past the xover in question, I bet the corner of the xover has the coil in it that is acting as an antenna.

If the amp power wire does go right past the xover box, and the amp does turn off with the HU, then pull the amp fuse at the battery temporarily and see if you noise vanishes. If so, voila. We'll bill ya : )

Had this get me for the first time in 1989, I believe. Was a right pisser too.