Car Stereos: want a headphone jack output, 2003 honda odyssey, headphone jack

Question
QUESTION: I have a 2003 Honda Odyssey that I would like to have a headphone jack in so that I (the passenger) can listen to the radio and CD on a VERY LONG road trip.  I don't want my kids to have to wear headphones while they watch movies in the back b/c they LOVE to converse with each other and I believe this builds relationships.  I just had a Pioneer system from Best Buy installed and they said it had a "headphone jack" that I found out after installation is an mp3 input jack!  What can I do!?  They've said if I find what I need they will install it at no additional cost b/c they told me I was getting a "headphone jack".  Thank you for your help!

ANSWER: Hi Linda,

I think there's a way to get what you're looking for using accessories that are available at Best Buy, but I need a little more information first.  Can you tell me the model number of the Pioneer head unit that was installed in your Odyssey?  Also, I'm assuming that your kids are watching movies on a separate mobile video system, rather than a movie player that's integrated with the Pioneer deck--please let me know if that's not the case.

I don't know of any head unit that includes a headphone output. Whenever you see the little jack on the front faceplate, it's invariably an input connection, not an output.  (Anyone selling or installing car audio equipment at Best Buy certainly should have known this).  Depending on the head unit, I'm pretty sure that we can find a way to add a headphone jack, but it will be much tougher to turn off the front and rear speakers while you're listening through the headphones.

If you can provide a bit more information about your new Pioneer system, as well as more details about the kids' movie player and how it works with the car system, I'll try to come up with a plan for you.

Thanks

Brian

---------- FOLLOW-UP ----------

QUESTION: The kid's system is an RCA portable DVD system and plugs into the cigarette lighter.  This is the only kind we ever plan to have with this van.  Also, I've been told by a car audio store here that I would have to basically disconnect the rear speakers in order to have what I would need.  I don't want to do this since the kids still want to listen to the radio and CD player at times too.  I am having the Pioneer system DEH-p6200RT taken out tomorrow morning (thursday) since it's not provided what we want and we payed $300 for it. Then we will just have the original Honda radio/cd player back in the van.  I've been told I have only 2 rear speakers...didn't know if you would need that information but I thought maybe that was important to trying to keep rear speakers since there are no "extras."  THANK YOU FOR YOUR HELP!

Answer
Hi Linda,

Thanks for the follow-up.  

I think that with a bit of custom work and a few parts, you can get what you're looking for. It would be easier with the DEH-P6200BT than with the factory deck, but you can do it with either, and you don't need to permanently disconnect any speakers.

Basically, you need two things: you need a low-level audio output that can be connected to headphones, and you need a way to cut off the sound to the speakers while you're listening to the headphones.

The first part is fairly simple with the Pioneer head unit.  It already has a full set of low-level outputs on the rear of the deck, and the output level should be about right for headphones.  The only problem is that they're RCA-type outputs, and they'd need to be converted to a headphone jack (ie, a female stereo 3.5mm jack).  This can be done using the adapter cable in this link:  
http://tinyurl.com/2387avu

I know the link says this is an audio input jack, but the connectors are all that matter, and it will work equally well as a headphone jack when connected to the head unit's RCA outputs.

You can also do this with the factory radio, but it's a bit more complex because the Honda unit does not have the low-level RCA outputs like the after-market deck.  However, you can get a device called a line output converter:
http://www.bestbuy.com/site/Fierce+Audio+-+Adjustable+Line+Level+Controller/1265

This connects to the factory speaker wiring, and gives you a low-level output that can be used with the adapter cable in the first link.

That gives you your headphone output.  The next problem is stopping the sound from the speakers without affecting the low-level outputs connected to your headphones.

First of all, you can cut the problem in half by adjusting the fader all the way to the front.  The head unit--whether it's after-market or factory--has only four speaker outputs.  You can shut off two of them by adjusting the fader control.  Now, instead of cutting off sound to four speakers, we only need to cut off the remaining two.

You can cut off the speakers using a device called a relay.  Basically, a relay is an electronic switch.  They're very commonly used in vehicle electronics, and Best Buy will certainly have some on hand.  The relays can be used to break the speaker wire connections, so that the speakers are temporarily disconnected from the head unit's outputs.  You can control the relays using a simple toggle switch--in order to cut off all connections between the two front speakers and the head unit, four separate relays would need to be used; but all four relays can be activated by a single switch.  (An alternative would be to use a pair of DPDT relays--this is basically a relay that can switch two wires at once, but it won't be available at Best Buy.  You might find it at Radio Shack.  Another option is a single 4PDT relay, but this would be even harder to find).

So in this scenario, if you wanted to listen to music through the headphones while cutting off all the vehicle speakers, you'd start by adjusting the fader control to the front, then flip the toggle switch to cut off the front speakers.  If the headphone jack is wired correctly, you'll be able to listen to the music solely through the headphones; the head unit's volume control would also affect the headphone volume.  The front speakers would be disconnected only when the relays were activated, and when you flipped the switch, they'd be connected again.  (It's important that the relays are powered using a key-switched power source, so they wouldn't stay activated when the key was off--they use enough current to drain your vehicle's battery over time).

Hope this helps!

Brian