Sorry ahead of time but I searched a few times and couldn't easily find what I'm looking for.

Dad's G35 that I'm helping him with.

Head unit died a while ago, so we did a dual din kenwood nav head unit with adaptor for the bose system. Now he's got a blown speaker or two so I want to replace all the speakers and add a powered sub. No aftermarket amp required, he doesn't blast his music. Head unit power is fine.

What size speakers do I need?
What spacers for the door?
Do I need to run new wires through the doors, or can I tap into something in the dash to get a signal to them?
What sub? I've had good luck with MTX and JL stealth boxes in other vehicles.

 

6.5"
Spacers vary based on the speakers you buy. zenclosures makes good ones - http://www.zenclosures.com/Nissan-In...infinitisp.htm
If you're keeping the bose amp, no rewiring is necessary - just replace the speakers and use existing bose amp and wiring - but the bose amp is the worst part of the system, so it's always a good time to change it.
I think the only custom-fit powered sub is the JL stealthbox - but there's good results from the cobalt SS sub, in either case you'll need to run power wiring.

I'll also add, if you're up for a relatively short drive (compared to others on the board) I'm in Georgia for a few more weeks and can help out, you just gotta cover lunch and sodas for the install.

 

Thanks for the help. I just found the instructions to bypass the factory amp- I plan to do that. Then I'll get 2 pair of 6.5 coaxials for the doors. That should allow the HU to power the speakers right?

Sub can be added down the road- for now I just need the speakers to work right.

 

The bose amplifier is receiving a low-level signal. That won't power speakers. You'll have to rewire at the headunit to send a speaker-level signal back through the factory wiring.

The front doors are components - separate speaker and tweeter - coaxial will sound bad with the tweeter firing at your feet.

While you're rewiring at the headunit, you'll want to run RCAs for everything (planning for the future) so you don't have to remove the headunit again when you decide you need more power for the speakers, since if you power the speakers off the headunit, they're going to be unable to keep up with the output of a powered sub.

So, run the five (or six, depending on headunit) RCAs from the headunit to just under the center armrest console (tons of space in there) or all the way to the trunk so you're ready for the future.

But, that said, a good 4-channel 300w amp can be had pretty cheap, and will increase the quality of your system IMMENSELY, so I'd really recommend doing that instead of running the headunit speaker-level output to the doors.

 

Can you explain that a little more? I'm running a kenwood H/U with metra adaptor. Where the signal getting knocked down to a low level? Shouldn't the speaker output be going to the amp?

 

I have a Kenwood Excelon I purchased about 7 years ago. I kept the Bose amp and swapped out all my speakers with 2 OHM Inifinity Kappas. I used to have a separate amp and sub just for bass as I got older though I removed it. I spliced into the existing wiring at the doors and used those to power the little crossover box then connected the speakers to those. I have the Zenclosures as well and they are pretty good.

He means low level since the Bose system comes with an amp there is very little power output from the stock HU. So, you would need to either rewire stuff or run new wires from the new head unit to your speakers. I might have explained it wrong.

I decided to keep the Bose and just replace the HU and speakers at the time, since it was easier.

Also, the only speakers actually made by Bose are the 6x9. The others were crappy Nissan paper speakers.

 

Speaker-level is high enough power to run a speaker off of - it's amplified by the internal amp of the headunit, so depending on the "quality" of the built-in amp, you're introducing noise and making changes to the sound of the signal. Low-level is not run through an internal amplifier, so it's a "clean" signal. It won't power a speaker, but lets you use a high-quality amp to get a speaker-level signal without any extra processing.

The most reliable way of keeping the bose amp is to feed the speaker-level signal from the new headunit to the PAC ROEM-NIS2 signal converter, which changes the signal into a low-level signal that the bose amplifier is made to accept (differential-balanced.... it's a complicated way of eliminating noise that requires processing on both ends of the signal wire). It's not the only way, but it's the most reliable. It's also possible to send the speaker-level signal directly to the bose amp using the metra 70-7550 harness and maybe half the time, it works ok, but the rest of the time it fails spectacularly.

So, you might be lucky in that your bose amp is one that gives decent sound with the speaker-level signal, but without seeing the full wiring setup, I can't guarantee that's the case.

 

I want to bypass the bose amp. So headunit directly to the speakers. Then I'm not using anything but the factory wiring.

So- if I hook the input/output wires on the bose amp together- it's out of the loop. The next question is if the adaptor from the kenwood headunit going to the factory wiring is putting the speaker level power out- I can't remember if I have the fancy box that cuts the signal down to low level or a simple adaptor connector to get the kenwood hooked the car.

 

Looks like you'll have to pull the stereo to find out, unless the box is visible by looking under the radio by removing the shifter trim.

 

I bought a non-bose adaptor harness from amazon for $5.80 shipped. We'll see what happens when we take the car apart this weekend. If it works, great. If not, I prepped my dad for buying a 5 channel amp and wiring kit and we'll do the whole darn system.

 

When I first ran a radio system in my coupe I ripped out all the Bose garbage, but used the Bose wiring so I didnt have to run new wires. Basically you run the speaker wires from the head unit, to the trunk, then back to the speakers. I cut off the harnesses for the Bose wiring so I could just connect the wires that fed the Bose amp to the wires that feed the speakers. Dont need to do anything fancy here. Just connect the speaker output wires from the H.U. to the Amplifier input wires, then connect the amp input wires to the speaker output wires. You bypass the entire bose amp and use the HU only. Also dont bother with the rear 6.5's and just put new 6x9's in the deck (unless it's a sedan)
I personally suggest JBL GTO series Components for the front and GTO 6x9 Coaxials for the back (unless it's a sedan). no spacers needed and they sound great.

 

Thanks, so the wiring will work. I already have Polk DB series 6.5 for the front doors and the rear sides? Now I'm wondering if I should do the 6x9 instead of the rear sides? Crutchfield website says their 6x9 won't fit in the rear deck- not sure why.

 

if its a coupe the 6x9's will fit, but its a pain in the a$$ to get them installed. you have to rip out all the interior in the back to get that rear deck out.

sedans had an 8" woofer back there.

 

It's a coupe. I'll stick with the 6.5's in the sides and the 6.5 components in the doors. Thanks.

 

Don't forget the massive quotation marks around "8 inch".