Want to have a mono amp to power my sub and a 2nd 4 channel amp to power my mids and highs without having to remove or replace the factory bose amp and just by splicing (if possible) .

I have a 2010 g37 sedan with bose and navigation.

Currently I have a sound qubed hdx3.2 subwoofer powered by a SQ 1250.1 amp. I installed it by splicing into the stock bose amp with rcas on one end and connecting rcas of the other end to the SQ amp. Works amazing and hits hard and had for a while now.

Recently wanted to upgrade the speakers so bought a Skar audio 150.4 amp and skar super tweeters and 10 inch mid ranges to replace the 10 inch subwoofers inside front doors. I’ve never installed a multiple channel amp before. How would I install my 4 channel amp so that it works with my mono Sq1250.1 amp? If I have to buy more stuff like a lc7i or LOC or splitters I’ll buy it but if it’s possible just by splicing into the stock system I would like to know how if anyone has done it. Thanks an advance hope someone can help me out!

 

In theory all you would have to do is either use low level inputs like a loc

Or get a rca splittler so you can run pull the same signal your amp is receiving

Though it would be better if you spliced PRE amp instead of getting POST amp that way you get a direct signal from h/u instead of the "enhanced" one from the Bose amp

 

Yes, as smokey grey says, best to tap the 4 low-level outputs of the head unit for your 4 door speakers.

The manual you want is here:
https://www.nicoclub.com/service-man...F2010%2FAV.pdf
you can download it at the bottom of that window.

Bose w/Nav section starts on page 355 and head unit pin-out starts on page 381.

 

so I should take signal directly from the HU at the front of the car by splicing with rca’s for my 4 channel amp? And plug those rcas into the 4 channel amp? And as for my mono amp (spliced into the bose amp rear +/- speakers) just keep it spliced into there? Sorry I’m just kinda new to this audio thing and never installed a multi channel before I just like learning lol.

also as for using a loc I tried using but got no sounds every time and many people have said it’s best to use rcas directly with no loc. So I’ll stick to using the rcas which have worked for me in my g37 and armada bose systems.🙏🏼 On my GTR however I just cut the signal from the stock 8 inch subs and spliced into those with a high in put cable and it hit hard.

 

also forgot to mention I don’t think my mono amp and 4 channel amp can be linked with rcas like most. My mono has only one output but it’s strappable with another SQ mono block. I tried plugging the rcas into both amps and got no sound from the 4 channel. So that’s why I’m just trying to see if it’s possible to just splice into the stock wiring with rcas and plug those into the 4 channel. Mono amp already spliced into the bose amp rear +/- speakers. Just trying to see where exactly to plug in my 4 channel amp

 

For your 4 main outputs LF, RF, LR, RR, that low level signal from the head unit is the way to go for your 4-channel amp. Is it mounted in the trunk? If so, it would be easiest to tap those signals off there, where they enter the Bose amp.

However, the catch is that I don't think there is a separate sub send from the HU, I think the Bose amp creates that ".1" output. And if you disconnect the inputs to the Bose amp you will also disable the sub output as you have set it up. But your monoblock has L+R inputs so in theory you could run a splitter cable and send LR & RR to both the sub amp and the 4-channel amp. Just think about which way you are likely to balance things between front and rear because the subs will only follow the rear channels...

 

Dope i will try this later and update.

 

tried this and it works but still get loud *** buzzing/engine whirl noise on the tweeters. It gets quieter if I turn down the gain on the 4 channel amp. Also now that I’ve done this the sub woofer doesn’t hit. if I balance the speakers to left and right on the infiniti display then it hits but if I balance it to the middle it won’t hit. Also if I disconnect one rca from the sub it will hit hard af but if I have them both plugged in it doesn’t hit. Apparently I read it can be out of phase but I have no idea how. I plugged in a set of rcas to my 4 channel amp (channel 1-2 are my tweeters) and on other end of rcas I spliced into front speakers.Then on another set of rcas I plugged in to the 4 channel amp on channels 3-4 (mid range speakers) and spliced those into my rear speakers. From those 2nd set of rcas I used splitters to the mono amp and the 4 channel amp. The Speakers work fine except the buzzing on the tweeters. Please let me know if i should wire in a 3rd set of rcas to the sub and splice else where instead of using splitters. On my armada I managed to plug in a subwoofer by tapping into the stock sub wires which were under the armada driver seat. Maybe I can tap into the stock subs for g37? Not sure what you would recommend from here

 

So pretty much I used numbers 23-26 (rear speakers) on connector b41 and the 2nd rca (mentions shoved) is tapped into those and plugged into the 4 channel amp (channels 1-2) and mono block. I read on another forum to use woofer amp instead (connector b43) on wires 8-9

Here’s the diagram for any other diy’ers
and get signals from there since it’s crossed over already. Will see how that goes. Only reason the woofer was working before was because one of the rcas wasn’t spliced in properly.

 

You're getting it. But I'm confused... are you planning to use the 4-channel in "bi-amp" mode? Like, 2 channels for tweeters and 2 for woofers? Are you running additional speaker wires to the tweets? Are you sure you don't want to just use the stock speaker wires and run passive x-overs with the new the door speakers? And are you planning to leave the Bose amp installed too? Just trying to understand your plan.

What you describe with the sub is definitely a phase issue, one of the tapped off pairs that you are sending to the mono block must be reversed. Here's how I read the wires carrying signal from the head unit to the Bose amp via connector B43. Mind the +/- and be sure +'s all go to the "center pins" of the RCAs...

LF + #35 Pink
LF - #36 Blue

RF + #33 Red
RF - #34 Green

LR + #24 Purple
LR - #23 Sky Blue

RR + 26 Brown
RR - 25 Yellow

Now about the noise... These wires from the head unit are balanced, two conductors in a shield. That shield is connected to pin 21 of B43. So if you are wiring RCA pigtails to these connections, they should probably be balanced too with the shield connecting at least on the Bose amp side where you are tapping in. You may also want to ground that shield at the far end where your 4-channel amp is, but try with and without. That might make things quieter.

I'm not a car audio guy, just know a bit about audio so don't count on my ideas...

 

yes stock amp still there. And yeah pretty much did what u mentioned by using both 1-2 channels for each tweeter and the bottom channels for each mid range woofer. So yes I ran wires all the way to the front for each speaker. The amp is 1000 watts and the tweeters are 250 watts each and mid ranges 200 watts each so I just assumed to use each channel. I’m a newbie to car audio so if u recommend passive x overs I will get them. And I mean the audio works really well and speakers are super loud just the buzz persists.

And also that wiring harness diagram I sent earlier was the wrong one. I tapped into b41 for all the speakers and b46 to the sub and now the sub works and speakers all work as well. But I will still check my connections for the speakers on the spliced rca side to see if my + connect with the center pins. These rcas I have aren’t labeled + or - and they’re blue and gray so I will check them out tomorrow morning. The b41 connectors is the same in both diagrams but for the b46 diagram I pretty much plugged in a 3rd set of rcas to:

1 - violet (sound signal woofer -)
2 - sky blue (sound signal woofer +)
I’ll include diagram below

also how would I “balance” the wires exactly just not understanding what I’m supposed to touch to each other. Maybe if I look at the wires in person I’ll have a better idea of what u mean

 

I really appreciate the help I know you’re probably like “man what is this idiot even doing” haha. Thanks for bearing with me 🙏🏼

 

No man, not thinking that at all. In fact, using the 4-channel in stereo bi-amp mode isn't even explained in the Skar manual so what you're doing is pretty advanced! As I said, I'm no expert so...

I think I understand now... Bose amp still in place, and in fact still running the rear door speakers?

If that's true, you would only need to tap off LF and RF signals from the head unit - at the Bose amp as you're doing - then use Y-cables to get into the 4-channel inputs...

Inputs 1 & 2 would be LF and RF, and you'd set the switches to "HPF" and 0 bass boost, then those outputs would drive new front door tweeters. The super tweeters fequency response curve starts at 2.2k so you can turn that "HPF" control on the amp all the way to 5k and the tweeters will handle anything above that.

Then inputs 3 & 4 would also be LF and RF and those outputs would drive your new door "mids" as you call them, though they're actually full range speakers. You may or may not want to use the "LP" switch on the amp for channels 3 & 4. In a true bi-amped setup you would kick that in and then adjust the crossovers so each speaker is only handling it's own part of the frequency spectrum. But I have the feeling this will sound great even if the new door speakers are running in "full" mode. Then in addition you have a choice of bass boost for those channels so you've got a LOT going on.

Tapping off the sub from B46 is the way to go - already summed and filtered. That polarity thing is no longer an issue although you still want to get it right for all the inputs and outputs to be running + as positive.

I guess you've already got it all working and now just chasing noise? This is where a real car audio guys would be more help than me. But I can further describe the balanced thing, as I understand it:

RCA connectors are traditionally "unbalanced" in that the "+" side of the signal is one center conductor and the "-" side is a shield woven around the outside. In a "balanced" cable like a microphone cable, there are two conductors, + and - , surrounded by a metal braided shield. That's why mic cable connectors have 3-pins. This is a better scheme for noise and interference rejection and clearly Bose thought it would be best to use this in our cars because that's how they ran from the head unit to the amp. That's why there is a +/- wire for each sound source AND a shield connection surrounding it all. I've never looked at the wiring harness so I don't know if each pair has it's own shield which is tied together at the end, or if there are multiple signal wires in one shield.

In any case, whining motor noise is always something that needs to be chased down in car audio as the power source has an alternator trying to supply constant DC voltage. So there are various line filters and things that the pro-installer guys know about, and maybe somebody can jump in here and make some better suggestions. But I'd start by experimenting with what should be grounded to what. Try grounding the Bose amp to the Skars, try grounding the cable shields, etc... You're almost there and it's gonna sound great.

 

A balanced output from an amplifier gives you a positive signal, an inverse of that signal which is the negative and these are in reference to a common ground (The Shield) The shield can be used as the return on an RCA connection but bypasses the CMRR (common mode rejection ration) improvements that a balanced amp provides. This screws up the output impedance of the amplifier and can result in unwanted feedback and noise. The voltages and current involved in line level signals are low enough that power consumption and energy dispersion should not be an issue but it is not the best way to do things. Either get a converter for each line you need to translate or look into a DSP/AMP that can accommodate balanced signals.

 

I'm far from an audio expert but I do understand the concept of noise in audio. First thing is to understand the likely source:

• Is the noise high frequency whine or low frequency rumble? Clicks? Pops? Static?
• Does the frequency of the noise change with the engine RPM?
• Do you have a specific ground cable running from the head unit to the amps?
• Have you cleaned all the specific ground connections to the chassis down to bare metal?
• Do you have a dedicated ground wire coming from the battery to the amps?
• Is the Bose amp and your aftermarket amps grounded at the same location?
• Did you ground any of the shields on the balanced outputs from the head unit?
• Do you have a lot of lights and accessories on the car putting a further load on the alternator?
• If I understand you correctly, you are running an aftermarket amp along with the Bose amp? If correct, is there the same noise on the Bose amps?