2005 Honda Odyssey, stereo severe feedbac

HELP ME

Can you believe that I can't find an installer here in Miami that can give me a resolution to this problem?

My van is a 2005 Honda Odyssey (Touring edition) which comes with mids, highs and a subwoofer with amp..  which they call their top of the line premium system.   Of course the system has no power and it pretty much sounds like sh*t to my critically listening ears..

So I bring my van into a very reputable audio installer's garage to upgrade my system.  I don't need much quad.. in fact I prefer a tight punchier sound than anything else. 

We agree on upgrading all of my mids & highs to MB Quartz and to build a custom box which will fit into my spare tire space in the back, using a JL 8" sub.. 

We installed two 4 channel Fosgate amps, one for the mids and highs and one for the sub.  I don't mention specific models because I think it's irrelevant to my situation. 

Here's the major issue that no one seems to be able to answer for me...

This model of Odyssey has a feature called economy mode.  The van switches from 6 cylinders to 4 cylinders whenever the car feels it doesn't need to be using 6.  For example if your cruising at like 50mph and you decide to let off of the gas pedal....... the car coasts, instead of coasting using 6 cylinders it will shift down to 4 cylinders. 

Well this downshift, if you want to call it, evidentally causes a current change in the cars voltage which in turn causes a severe feedback into the subwoofer.  The feed back gets so deep it almost sounds as if I have a few 15" subs in the back.  It's a painful sound to hear and I have two daughters under the age of 3 which makes this most definitely untolerable.

The system itself sounds top notch...  The installers did a wonderful job.  Looking at it with a critical eye the installers were every bit professional, but this feedback issue has left them stumped.  They have tried everything you can imagine.  I left the car with them for 4 days and they still couldn't resolve the issue.. He even told me in his 22 years of experience he's never had an issue like this which he wasn't able to resolve.

Ultimately, I had the entire system removed and now I'm left with my stock system.  It has been a real let down for me.  It's a brand new van and I wanted it to sound as good as it looks and from the feed back I've received it's impossible.

Some body please help...

Feel free to contact me personally any time at (786) 344-5412....  I'm on eastern standard time... 

My name is O.J. 

Not being there the only suggestions that I have are the following:

• if in fact there is a voltage drop that would affect the performance of the amplifier when the transmissions switches from 6 cylinder to 4 cylinder, I would run a power wire from the alternator ( fused ) directly to a Optima battery designated for the audio system. This will isolate the power from the rest of the system and the affects of the voltage drop from the rest of the car
• If they used a PAC trunk LOC they would have been able to use the low level output of the OEM radio & converted it to RCA outputs.
• Make sure to test the power wire off the battery for the amplifier's to see if there is infact a voltage drop when the transmissions drops from 6 to 4 cylinders. Also test the voltage from the preamp wires on the LOC for any drop in voltage.
• Check for an absolute ground on the LOC as well as the amplifier to ensure proper grounding location.
• I'm sure they used triple shielded RCA's

Talentco

Hey Im in Lauderdale, take it in to the honda dealership take it to Coral Springs Honda if you can and have them disable the economy mode, my wifes mother has an Odyssey and she hated that feature, the dealer charged her 200 bucks to do it, since it required rewiring and reprogramming of the computer

But thats only one idea.. im sure others will add more to this thread

Later

Did she have it disabled because of audio issues or because she just didn't like that feature?

I handed the installer your ideas and they said that running a wire directly from the alternater would damage the altenater in a few months.. then I specified that it would be attached to a dry cell, they were like.. hummmmmmm maybe..

They also said that they did check the voltages while driving and that there was no flucuation in voltage output from anywhere. 

I'm taking the installer at his word when he says he did these tests while driving the car...  at this point everything has been taken out and we are not planning to re-install. 

The owner of the store was also given  a copy of your ideas and his first comments to me where, "Where did you get this?"  He liked the idea of running a dedicated line to a dry cell.  I'm contemplating letting them have another go at it.  They refunded me all of my money.

I don't know if I'm willing to have another go at it.

Do you think that the alternater stands a chance of being damaged in this scenerio?

OJ

She had it disabled cause she hated that featured, it would lag when she needed to jump into the throttle

Hi,

I think the noise you are experiencing is basically white noise.  Honda uses it to mask the sound of the engine when running on three cylinders.  At least that's what I heard described on Autoweek.  Not sure if the dealer can deprogram the masking feature though.  Just my two cents.

Mark

 Are u telling me that this white noise is audible?  Is it produced through the sound system?

The freakiest thing about it all is that we got the feedback even when the stereo power was off.

The sub and amps were triggered by the ignition...

The alternator will probably get damaged over time if you directly wire the power wire to the amplifier's. The amperage draw would be too much for the stock alternator to handle. The idea of having a secondary battery was to isolate the stereo from the rest of the electrical system & also supply the required power to the audio system without straining the OEM system. Glad he liked some of my ideas, but in the end, you'll have to see if the isolation method works. In my mind it does, but your still feeding off the audio preamp signal and this maybe the problem. As long as he probed the wires while driving and deduced that there was no problems on the preamp signal going into the PAC module, then I would start looking elsewhere, but I would get a second reading on that preamp signal if all else fails.