Tenshots1

Hey All,

I have been researching like crazy but I am hoping for a definitive answer before either pulling the dash back apart or purchasing additional parts for my stereo system.

This weekend I installed a XAV-AX100 in my C5 corvette using a Metra Axxess (did not adjust the screws). I felt the install went fine, but this morning I noticed I am getting no bass from my front speakers. It appears that the Amps in the front speakers are not turning on. When doing the install, I noticed that there was a 4 prong plug on the car that did not plug in anywhere to the Axxess system. I am thinking this is the plug that runs the amps. Based on research ive done, ive come to some potential conclusions that I am hoping to get guidance on:

1) I think the 4 prong connector that didnt get plugged in had a blue/white wire on it. Per some threads, I can connect just this wire to a power wire and get the amps to turn on. Is this correct?
2) Some people said that simply playing with the Axxess adjustment screws fixed the issue. This would infer that #1 is incorrect and that the 4 prong connector does not need to be hooked up, but the settings simply need to be adjusted for the amp to run. Is this correct?
3) I was planning on switching the speakers down the road to a 6.5" up front (with faceplate) and 6.5" in the rear, thus ditching the door subwoofer all together. I would rather have better sound and the speaker should produce some bass. Can this be done by simply swapping equipment at the doors and not touching the stereo in its current condition? Can I use the same speaker wires and simply throw those adapters on them?
4) Would it be better to swap the front speakers with new factory size speakers and keep the sub around?

Thanks all for the help!

GCG

I'm going to try to clarify things for you as requested. There's a lot of confusion and I think it would be easier if we first define the basics.

The C5 OEM Bose system's 4 main channels are composed of 2 front 3½" and 2 rear 5¼" (or 6½" if a coupe) twiddlers and all 4 of them are directly driven by the headunit's built-in 4-channel amp. In addition to that, each door has an 8" subwoofer directly driven by a dedicated amp that is mounted right besides it. Installing a new headunit using an AXXESS interface preserves this structure.

That being said, the 2 more common causes for not getting any bass from the door subwoofers are either:

• the subwoofer amps are not turning ON, or
• the AXXESS adjusting pots are all the way to 0

For the door subwoofer amps to be able to turn ON, when you wired the harnesses, the Blue/White wire from your headunit must had to be connected to the Blue/White wire from your AXXESS. If you did, and the door subwoofer amps are not turning ON, then you need to check Fuse 28 and Relay 45 in the passenger's footwell fusebox.

Otherwise, you need to check the AXXESS adjusting pots and fine tune them. It would be wise to check as well your equalizer and filter settings in the new headunit.

The OEM headunit has 4 connectors: C1, C2, C3 and C4. Only C1, C2 and C4 are connected to the AXXESS adapter. C3 remains unplugged.

So, going back to your list:

1. Connector C3 has nothing to do with the subwoofer amps. Don't touch it. Amp Trigger wiring already explained above. Double-check it.
2. Already answered
3. (Skipped)
4. Definitely. If you really want to take this to another level, you should consider replacing the 4 OEM Bose twiddlers (not just the 2 front 3½"). Click here for more details and recommendations. Click here for additional tips.

Tenshots1

That was super helpful, thanks CGC. I have been reading a lot of your stuff, so I’m pumped you addressed my questions. I have GX602s sitting in my amazon cart after your recommendation on another thread.

Anyway, I was able to check the fuse and relay. No issues there. Sounds like I will be pulling out the stereo and checking the blue/white wire, which I am 99% sure is secure, then adjusting the tuning. I did not touch the tuning when installing the axxess, so my guess is they are at zero. I got so frustrated doing the install with the terrible vetnutts brackets that I totally forgot to check the functionality prior to putting everything back together.

So, if you were to recommend just a speaker upgrade, would it be a 3.5” front speaker and 6.5” in the JBL 2.3ohm? This would be better than converting to 6.5” up front as well?

GCG

You're welcome! It was my pleasure to give you a hand on this

Get the JBLs GX302 (3½") and GX602 (6½"). Don't touch the OEM door subwoofers. It's the easiest most bang-for-your-buck upgrade you can do that provides the most positive difference. Just pay attention to the installation tips I linked for you in my previous post (this is critical).

Check this independent review of the JBL GX Series. I'm sure you'll find it interesting.

Also, when adjusting the AXXESS pots, don't overdo it or then it will seem that your rear channels are playing lower than your front channels. Click here for more details and directions for adjustments to achieve a better balance.

Tenshots1

For anyone with similar issues in the future: the problem was that the metra harness channels were all turned down to zero. I increased all of them to about 75% and now it sounds great. Much happier!

GCG

I'm glad it was just that