I know there's bits and pieces of this subject all over but I can't seem to hone in on the answer I need.

Current: 2007 G35 sedan with Bose

PLAN:
-Keep head unit. That's just a mess and I want to resell with dash face as is.

-Replace all four doors speakers

-Get an amp like the small 4chan Alpine KTP 445U amp for the four doors. I need the rears because my kid listens to his music/ stuff back there so he wants to hear it.

-Disconnect Bose amp and sub and just use a sub/amp combo box with a line ran from the battery.


Questions:

1. With that Alpine amp I should get 4ohm door speakers correct?

I ordered one pair of the 2ohm infiniti Kappas components before I found the small amp. Should I return and get different now?

thank you greatly

 

Keeping the factory headunit is questionable just based on its longevity alone. These radios are a flawed design from the factory, so if you still have one working, consider yourself lucky. Swapping out the headunit lets you use any amplifier, while if you keep the bose unit, you need an amp that takes a differential-balanced audio signal. JL Audio amps all do, other brands are a model-by-model basis, and generally hard to find out if they do. An amp that isn't designed to take the signal will generally be quieter and noisier since it's not interpreting the full signal.

Your kid will hear the music fine from the front speakers. Concerts, live shows, people talking to you. All of these things happen with audio sources in front of you, and it's natural to listen to things this way. Putting more money and power into quality speakers in the front will give you better overall audio in the entire car.

The factory speakers are all 4 ohm, but the tweeter and speaker in the front are run in parallel, so overall 2 ohm load there. Not a problem as 99% of amps are 2 ohm stable.

 

So if I were to do the HU. It's a matter of being able to keep the steering wheel controls and such. Any suggestions? I can PM you too.

 

In case anyone's paying attention on this thread - it's an 07 sedan. I don't have any confirmation that the 07 uses a differential-balanced signal at all, and I can't confirm that the speakers are 4 or 2 ohm in the 07 sedan. Using a JL amp would still be an assurance that it'd work though, and I still recommend front soundstage.

 

I think I have come to just adding an amp/sub and bypassing the Bose amp/sub.

Was there ever a conclusion as to if there was a clean line from the HU to the Bose amp that can be tapped as opposed to needing an LOC?

 

If it's between the bose headunit and amp, it's a clean, line-level signal. No LOC required. Whether it's a differential-balanced or not, no idea, but a LOC doesn't help with that anyway.

 

So I should tell the install people who of course want me to buy "their" LOC and pay for install to shush and just find the clean HU line.

Or look at a line driver I believe it is?

And thanks for response.

 

LOC takes speaker-level and makes it line level. It's already line-level coming from the bose headunit. The only reason you'd need an LOC would be if they put it AFTER the bose amplifier.

All you need is an amp that takes differential-balanced signals.

 

Thanks again Wrath.

I'd love to get JL but they are a bit much. I am looking at the Rockford Fosgate P300-10 combo box. It specifies it has separate low level and speaker level inputs. Would this still negate needing an LOC?

Side question: I listen mostly through Bluetooth and MP3s which of course makes songs loose "oomph" a bit. Is there a way to restore this without too much expense or complication? I see the Epicenters but not sure.

 

The RF won't take differential-balanced signals. If you take the signal AFTER the bose amp raises it to speaker-level you may want an LOC, but the speaker-level inputs should be fine.

Bluetooth, theoretically transfers at a bitrate higher than just about any MP3, but it still is an audio conversion, so you're going to lose some quality, but probably not perceptibly. MP3s at any decent bitrate shouldn't sound any different from a CD, especially when road and wind noise comes into play. Crappily encoded MP3s though, yeah, you're going to get that "underwater sound" on cymbals and such at the high end.

 

I suppose I should just get a quality LOC out from the Bose amp to use the better low inputs on the RF amp.

I just worry about the signal being too "processed" coming out of the BOSE amp.

 

The bose amp does a TON of processing in the 03-06's, so before doing the LOC route, try running the amp to the low-level inputs.

 

Low level before the amp, got it. I will look in to it.

 

In case anyone ever needs. 2007 G35 Sedan Audio, Visual, Navigation Service Manuals with wiring and pin-outs ... with and without Navigation/BOSE combinations.

http://www.nicoclub.com/service-manu...7_G35_Sedan/av