2009 G37 Sedan Studio on Wheels Subwoofer Replacement

[vetes]

Like many others I am dissapointed in the parcel shelf mounted "subwoofer" in my Bose Studio on Wheels equipped G37 sedan. I am not looking for trunk rattlling, glass shaking sound but I would like some thump at lower volume. When I turn the volume up it gets better but it just seems hollow without enough bass. I have searched these forums and have learned some and now it is time to improve my system. I am looking at two options and appreciate any information regarding technical specifications, personal experience and advice. I will include every step taken along with pictures and a review of what I hope to be improvements.

From what I understand there is a 10 inch subwoofer/amplifier assembly. I cannot verify anything because there just isn't enough information out there. There is a single woofer under the center of the rear deck. Here is an image of the label:



So, it is a Bose shallow mount Nd woofer with a model number of 28138 JK11A, unfortunately there is no success searching for that model number. So I cannot easily identify its specifications.

From what I have read here and other places it is a 2 ohm woofer, and it measures about 6 inches of mounting depth total.

My first option is to add an Infinity Basslink, and from what I understand it should be easy enough to create RCA type links out of the current woofer amp.

Second I could replace the woofer with something like a Rockford Fosgate Punch P3SD210 and replace the current amp with a Rockford Fosgate Punch P300-1. It's a two ohm setup that gets rave reviews.

Any opinions out there as to which method is preferable? Any tips or comments on the feasability of this project? Thanks for the help.

[CougarRed]

My first option is to add an Infinity Basslink, and from what I understand it should be easy enough to create RCA type links out of the current woofer amp.

I have read several reviews of the Basslink conking out after the 1-year warranty expires. I wouldn't buy it without an extended warranty.

Further, Rockford Fosgate makes a similar and presumably superior product called the Punch Overload. It's larger (22"W x 16"D x 12"T) than the BassLink (15x13x8). 300W vs. 200W. The Basslink II is 16x16x9 and 250W.

Both the Punch Overload and Basslink are Crutchfield Signature Products. If you go through them for your installation, wiring and extended warranty, you are looking at $825 out the door for the Punch Overload and $420 for the Basslink. JL Audio makes a similar product called the Power Wedge Max.

[joe603]

I'm with you! I also have a 2009 G37 sedan with bose and want to increase bass output. Here's a good post that I started for some reference:

g37-subwoofer-install-and-oem-intergration-t486429.html

I've put some wiring diagrams on there and pics of my last set up...and ideas for this build.

The OEM Bose system has a 10" shallow mount sub with an integrated amp in the rear shelf. The main Bose amp is nearby. My plan is to use the signal from the main bose amp to the sub amp. It should be a low voltage signal that can be used for the aftermarket amp input. There is also a remote turn-on lead to use for the amp.

I've considered using the input from the deck, but I'm not sure on how to split the signal without creating noise or a loss/degradation of signal.

[CougarRed]

Many G owners have used the JL Audio 10W6V2 sub with the JL Audio 500/1v2 sub amp with good results. There's even a Do-It-Yourself floating out there on the internet.

Personally, I am going with the Punch Overload solution. Should come in later this week, and I'll have it installed by the weekend.

[vetes]

Thanks much for the quick replies and suggestions. Thanks for linking your thread joe, the wiring diagrams and discussions were very useful. I think I may be leaning towards a powered box one and done type solution, the JL PWM110-WXlooks good.

http://mobile.jlaudio.com/products_encl ... rod_id=588

I don't need too much and Crutchfield includes a full wiring kit, not bad.

[CougarRed]

Thanks much for the quick replies and suggestions. Thanks for linking your thread joe, the wiring diagrams and discussions were very useful. I think I may be leaning towards a powered box one and done type solution, the JL PWM110-WXlooks good.

http://mobile.jlaudio.com/products_encl ... rod_id=588

I don't need too much and Crutchfield includes a full wiring kit, not bad.

You are going to want to tap into wires 23-26 or 33-36 coming from the head unit. Not wires 8-9 from the large Bose Amp to the smaller OEM amp.

[audtatious]

I'm with you! I also have a 2009 G37 sedan with bose and want to increase bass output. Here's a good post that I started for some reference:

g37-subwoofer-install-and-oem-intergration-t486429.html

I've put some wiring diagrams on there and pics of my last set up...and ideas for this build.

The OEM Bose system has a 10" shallow mount sub with an integrated amp in the rear shelf. The main Bose amp is nearby. My plan is to use the signal from the main bose amp to the sub amp. It should be a low voltage signal that can be used for the aftermarket amp input. There is also a remote turn-on lead to use for the amp.

I've considered using the input from the deck, but I'm not sure on how to split the signal without creating noise or a loss/degradation of signal.

Just use the connection to the factory sub and run it into an amp that support speaker-level inputs.

[CougarRed]

What I have learned:

1. The signal coming from the head unit is not digital. It is low line level analog.

2. Lines 23,24,25,26 are the rear head unit outputs. Lines 33,34,35,36 are the front head unit outputs.

3. The low level signal comes from the head unit to the Bose amp (Rear 23-26, Front 33-36). The Bose amp then adds it's processing, amplifies the signal (now it's a high level signal), and powers the small OEM woofer amp through lines 8 and 9.

4. Some people have used the woofer amp out for the sub amp high-level input. I personally think it's a lot better to just use the clean signal from the head unit. The small OEM woofer output already has Bose signal processing applied to it. I don't think you really want the additional Bose processing applied to your subwoofer. There might be a high pass filter applied which might take some of the low frequencies away.

5. All of the Bose processing happens in the Bose amp. That means the signal from the radio head unit to the Bose amp is NOT processed and is a clean signal. You should just be able to put RCA tips onto those lines and plug them directly into a sub amp.

6. Restated, in our Bose system, the signal processing is done in the Bose amp, not the head unit. So from the head unit to the Bose amp, you have a clean relatively flat signal that can just be hooked up to an after market amp as if it were coming from an after market head unit. Anyone that is throwing in an after market amp and speakers, whether that's just a sub and amp or many speakers and many amps, the signal before the Bose amps can be tapped and will provide a solid signal from the OEM head unit and still maintain all OEM head unit functioning (fade, bass, etc.).

7. I would therefore highly recommend using the head unit output for an input into a subwoofer amp. If you choose instead to tap into wires 8 and 9 from the Bose Amp to the small OEM woofer amp, you will need to use a high to low-level converter (some sub amps have this built in). But it doesn't make any sense to convert it to low level when you already have a low level signal from the head unit.

8. As for choosing between lines 23-26 (rear) or 33-36 (front), you can use either pair, but you may want to choose based on whether you like to fade front to rear. Not sure if you are planning on having a remote level adjustment for your sub amp or not. I would. If so, then tap into lines 33-36 for your sub amp. If not then use the rear set of line level (23-26) so that you could fade from center to front in order to cut the bass if you desired.

9. In addition to allowing you to fade the subwoofer, using lines 23-26 or 33-36 from the head unit allows you to control the subwoofer using the bass setting on the head unit before any boosting of the sub via remote control.

[audtatious]

The best solution is still the most costly, use a CleanSweep and replace all speakers and amps.

[CougarRed]

Replacing all the amps and speakers would be costly (the Zapco DC Reference amp is the nuts)! But I see no need for a CleanSweep in our car. Here's what I have learned:

Although some OEM car stereo system head units send a processed signal that require a DSP to flatten out the frequency response of the signal that signal, the Bose system in our car does not. The signal coming out of the head unit is a line level flat response signal with all DSP activity occurring in the OEM outboard amplifiers.

In actuality, CleanSweep will degrade the signal from our head unit since it will be going through two transformations steps of the signal--Digital to analog from the HU, back to digital in the CleanSweep and then back to analog. This is not to say that other DSP's, who also accomplish other processing functions, don't have their place.

DSP's like Clean Sweeps and RF 360.1 were introduced since many people wanted to retain their OEM head unit, but a lot of times these signals were already processed from the HU. Clean Sweep was first and what it did was take this processed hi level signal and then flattened them out and summed them together. This way you could add after market systems and not be stuck with the BS frequency responses the OEM systems had been putting out. Then 360.1 came out with other things besides this signal summing/flattening, like time alignment.

In our Bose system, the signal processing is done in the Bose amp, not the head unit. So from the head unit to the amp, you have a clean relatively flat signal that can just be hooked up to an after market amp as if it were coming from an after market head unit. Someone can waste money and put a Clean Sweep AFTER the Bose amps and flatten the response, but Bose changed the response so it worked well with its speakers in our particular car.

Anyone that is throwing in an after market amp and speakers, whether that's just a sub and amp or many speakers and many amps, the signal before the Bose amps can be tapped and will provide a solid signal from the OEM head unit and still maintain all OEM functioning.

[joe603]

Sounds good to me! So how do you "tap" the signal before it gets to the Bose amp? I still need to use the Bose amp for my mids/highs. What device do you recommend? I see where it comes into the Bose amp on connector B41, 23-26. Will adding a device induce noise?

[CougarRed]

Sounds good to me! So how do you "tap" the signal before it gets to the Bose amp?

From what I have learned, you must know how to solder!!

When soldering your RCA's to the positive and negative wires from the head unit, solder the positive to the CENTER connector of the plug and the negative to the outside connector. In other words, you want the penile part of the plug to be connected to the positive signal from the head unit and the the wide outside ring of the plug to be connected to the negative feed from the head unit.

Pull the wires from the input of the amp and solder the RCA right there, unless you need longer wire than you will have to use different wire to make it longer and then solder the RCA's to the extension. Remember, there are 8 wires coming from the head unit: FL, FR, RL, RR, a positive and negative for each. If you are keeping all of your speakers and just trying to add a sub and amp, then you need to pick a pos and neg set to tap into. Realize though that you will be only taking signal from one channel, but won't really matter since sub frequencies are usually run mono.

After the soldering is done, you can use some heat shrink and techflex to cover the joining area between the wires and where the RCA meets. They can be gotten from partsexpress.com, which also has good RCA plugs.

[joe603]

When you do that, does it cause any degradation in the signal level going to the Bose amp?

Just to be clear, I'm tapping into the signal coming from the head deck, before it hits the Bose amp right? I could probably use the rear leads and have another way to control bass output. Sorry, I'm not an installer...this might be the normal way to do it.

Plus, if I pull the signal from the head deck, I can keep the OEM sub active...which would provide rear fill.

[CougarRed]

1. When you do that, does it cause any degradation in the signal level going to the Bose amp?

2. Just to be clear, I'm tapping into the signal coming from the head deck, before it hits the Bose amp right?

3. If I pull the signal from the head deck, I can keep the OEM sub active...which would provide rear fill.

1. No.

2. Yes.

3. Exactly.

[joe603]

Perfect, thanks!

[audtatious]

Although some OEM car stereo system head units send a processed signal that require a DSP to flatten out the frequency response of the signal that signal, the Bose system in our car does not. The signal coming out of the head unit is a line level flat response signal with all DSP activity occurring in the OEM outboard amplifiers.

Did you check the signal for processing or have access to a schematic? Just curious. The last Bose system I dealt with (2k2 Maxima) did processing at the head and not the amps. I ran a PAC adapter to a PPI PAR-225 to allow me some additional control to adjust for HU curves.

[CougarRed]

Not sure which schematic you are looking for.

Here's one: http://www.g37-tech.com/wiki/Audio_Syst ... _Locations

As you can see, the line runs from the head unit to the main Bose amp in the trunk. From there, the Bose amp powers the front speakers. The Bose amp also sends a line to the small OEM amp on top of the Bose amp. That amp powers the rear deck speaker(s).

The line coming from the head unit to the Bose amp in the trunk is low level analog.

[audtatious]

The link shows the standard wiring layout in regards to the wire runs but not the pinouts nor any reference to signal processing. The signals can already have been adjusted via the HU prior to being sent down the pipe. For more information, check out the AV pdf in the FSM.

To make clear, I was simply asking if you had anything that showed the new Bose systems in the G37 do not perform signal processing at the HU. I simply don't know if it does or not. I know the 2k2-2k7 Maxima did, the G35 system did, etc. Car manufacturers commonly set the systems to lower bass output as you crank up the sound as a way to avoid costly warranty work due to blown speakers. The new G system may not do that but I have yet seen anything that says it doesn't.

[joe603]

If the G35 bose system did, I couldn't hear it in my system for the coupe. It was LOUD at high volume! The new G37 system only has front/rear coming from the head deck...I can't see it messing with the signal when the system has a dedicated "sub" amp/woofer, plus 10" speakers in the front doors. But, you never know. Even if it did, it won't matter with a decent aftermarket sub setup.

I'm still hesitant about tapping off the signal before it gets to the main Bose amp. What do you think Matt?

[audtatious]

I saw numerous people comment on the conditioning the G35 received. My G35 has the Studio on Wheels so I'm not sure about the prior gens. From a coupe perspective I don't notice any lowering of bass but would have to go through the diagrams to see where the xover's are for the various speakers (I believe the factory tweeters have a capacitor for 6db but I'm not sure of the others). The various wires from the factory unit send independent front and rear, L+R, signals to the amp(s) for each speaker it seems, via the plug pin out's. If I were to consider upgrading the factory system and continue utilizing the factory HU I would like to know where the xover scrubbing comes from.

FWIW, the Music on Wheels system in my coupe is much cleaner and tight than the one in my wife's G35s.

To answer your question it kinda depends on the above. I would personally prefer a full range signal directly into an external sub amp and use the amp to set the aftermarket subs xover levels. If the sub output from the HU is pre-conditioned it pretty much makes that impossible and you would be limited to the factory crossover settings. I really have not dived into the wiring schematics in the FSM enough to determine an appropriate source to use.