2 Head units down the drain

[superbase]

So I have sunk $1000 in labor costs trying to get 2 different head units from 2 different shops to work in my 13 nismo with Bose system and both have utterly failed. The #1 problem is over-amplification of the audio and steering wheel controls. For starters, I can only crank the volume up to about 10% at which point the speakers become so ridiculously loud it hurts your ears. You can also hear a kind of "hissing" sound when songs fade out or if you pause them, the kind of sound you would expect to hear if you turned your stereo volume up to 100% without playing anything. And of course total failure of the steering wheel controls.

Whats going on here? Why cant anyone get a head unit to work in this thing? I dont know squat about car stereo's, so I cant understand all their technical jargon while they make excuses about what went wrong. They keep talking about hard wiring something through the bose amp, whatever that means. Are they supposed to bypass the bose amp entirely and just splice together the speaker wires with RCA cables and plug directly into the back of the head unit? Is the HU itself an amp? Or are they supposed to tie the new HU into the existing Bose amp in some unique way to prevent what sounds like double amplification?

Head units connected have been

Pioneer 270BT and Joying Android Head unit. Both sounded exactly the same.

At this point I'm just going to have them put the stock HU back in and I'll run a dang cable to the AUX in port, this is ridiculous.

[DeliriousClam]

Sounds like they're putting speaker level output into the amp which is a no no. Need to use a Line output converter to drop the levels. As far as the steering wheel controls go, if you have bluetooth controls, it's a little different. Bigaudiofanat can probably go much more in depth than I can.

[JARblue]

Did you read this thread? Seems pretty straightforward. Interesting that two different shops were too incompetent to do the work.

What to know about Bose

[superbase]

Originally Posted by DeliriousClam

Sounds like they're putting speaker level output into the amp which is a no no. Need to use a Line output converter to drop the levels. As far as the steering wheel controls go, if you have bluetooth controls, it's a little different. Bigaudiofanat can probably go much more in depth than I can.

Yeah I read the thread on Bose systems but couldnt understand it. I guess I could just direct the installers to that thread and let them study it. Is an LOC a common thing to include when upgrading stock systems? Or is this just some hack to make our systems work? Is it possible to avoid the bose amp entirely and just have all the speakers connect to your own new amp that also powers a sub? Would that be the better solution instead of trying to piggy back off existing hardware?

[DeliriousClam]

Originally Posted by superbase

Yeah I read the thread on Bose systems but couldnt understand it. I guess I could just direct the installers to that thread and let them study it. Is an LOC a common thing to include when upgrading stock systems? Or is this just some hack to make our systems work? Is it possible to avoid the bose amp entirely and just have all the speakers connect to your own new amp that also powers a sub? Would that be the better solution instead of trying to piggy back off existing hardware?

LOC is a common thing when installing an aftermarket headunit into a system that has a factory amplifier. The other options are buy the wiring harness which has RCA's on the ends (don't remember the metra model # off hand) or bypass the factory amp which can be a bitch. I've never done it on a Z before so I couldn't tell you how hard it is.

[RonRizz]

Deliriousclam hit the nail on the head. They are trying to put a high level signal into an amp that is probably less powerful than the head unit itself. This is why you have so much system noise (hiss) and the audio is blaring at low volume settings..... Any shop that cannot perform this task would not be anywhere near my audio system. I may drive by and let them look at it, but they wouldn't be touching it.
The shop should also refund your $$ for the install. How could they turn the car over to you like that in the first place? I'd be HOT.
by the way, I hope the $1000 you quoted was an exaggeration......unless it included the head unit..

[YzGyz]

I would have to mess with the unit to figure things out but it sound like a amped signal input into the OEM amp which in turn blast speakers. It should not be that hard. I mean a amp just need a signal and they it increases it and pushes it to the speakers. According to the metra harness diagram, you just need to hook up the front speakers and the sub and it should at least play decent.

Who Wants Bose Wiring Diagrams!!

IDK, I would personally have to mess with it to figure it out.

YzGyz