2005 Honda Odyssey, stereo severe feedbac

more info....honda active noise control

http://www.google.com/search?hl=en&ie=ISO-8859-1&q=honda+active+noise+control&btnG=Google+Search

Even though the stereo was physically off via the power switch, i bet the speaker outputs still have signal (masking noise) on them, hence the output you have is just being amplified by the equipment you added. 

Great system that ANC !! The only thing that I can see being a problem is that OJ mentioned that the problem still persists with the radio off and the ANC activates only in 3 cylinder mode. Now what we need to know from OJ is when the feedback occurs, is the engine running ( idle ) or with the key in the ON position, but not started ?

Another thing is, does the van engage the ANC feature right off the bat from idle or does it start in a 6 cylinder and then drop down to 3 cylinder's after it idles for XX amount of time ?

How bout them apples........... Thanks WEEN

Active Noise Control

A feature found in many luxury cars, Honda's Active Noise Control was specified for Accord Hybrid to counteract the extra noise created by the imbalanced motion of the car's V-6 engine when the VCM system deactivates the rear engine bank's three cylinders. In this condition, the booming noise of the engine is more spread out, and thus more noticeable to the naked ear.

The ANC uses input from the engine's ECU and microphones in the cars interior - one mounted in the front headliner and one in the rear parcel shelf - to monitor noise levels in the passenger cabin. When the ECU puts the i-VTEC V-6 engine in 3-cylinder mode, a control unit synchronizes the booming noise created with an opposite phase signal sent through the car's audio system to essentially cancel each other out. The result is an audio signal with an opposite wave and a very quiet interior. ANC works whether the radio is on or off.

The Active Noise Control is only active when the engine is in 3-cylinder operation, and operates regardless of whether the audio system is on or off. The microphones are tuned to only recognize the engine booming noise - passenger's conversation, the audio system, or excess road noise have no affect on the system.

Now I just need to find out if this is also true in the Odyssey

I definitely never noticed it when it was in idle or when the van was turned on.  In fact it seemed to occur mostly after the van was warmed up and only when the van went into ECO mode. 

After reading the link "WEEN" posted, I think we found the root of the problem.  Now if there were anyway to disengage that noise cancelation feature, then we'd be on to something.

here we go:

In fact, the Odyssey models with VCM are especially quiet because those vehicles are equipped with Active Noise Control (ANC) technology that works with the audio system to effectively cancel inherent noise produced by the VCM system (along with some road noise). Additional NVH dampening occurs through the use of an Active Control Engine Mount System (ACM) that uses electrically activated dampers to minimize engine vibration for an incredibly smooth and quiet driving experience.

That's gotta be it!

Yep thats it, take it to the dealship and order them to disable it

Boy that's alot of acromyns going on there. You almost have to have a PH.D or have a P. ENG to understand some of those HTDA ( hard to decypher acronyms ) 

I'm going to call them now....  SKOLDSPUPPY..  I imagine that you don't have a contact to the mechanic in Coral Springs who did that job for your in-law.  If u happen to then I would appreciate the contact info.  I guess it's best for me to go to the Honda garage and speak to the mechanic directly.  We'll see.....

As Soon as my mother in law gets back from her gambling trip to vegas I'll get you the name of her service advisor, she's back on tuesday

Later

Thanks SKOLDSPUPPY...

I called the honda mechanic here in town today and he didn't know about that feature..

He welcomed me to come and find out about it in their service book then they would work from there..

they were really busy when i called... I'm thinking about just forgetting about the whole thing all together...

I will post if I do decide to.... and let the board know of the outcome