iPod Car Audio Direct Connect

by Trygve Isaacson, copyright c2004

There are a couple of well-know ways to adapt an iPod or other portable music player to a car stereo without permanently hardwiring it in: the most common are an FM transmitter such as the Griffin iTrip or Monster iCarPlay or iRock, and cassette adapters made by Sony and Radio Shack. (The Monster iCar Play is nicer than the other FM transmitters because it provides power and charges the iPod.) But if you have a multi-disc CD changer in the car, you may be able to get a direct audio connection from the iPod to the stereo with very little effort and no permanent alteration to the car. The fidelity will be better than is possible via FM or a cassette adapter. Here's how I did it.

Requirements

Access to the head unit's CD changer audio input cable (presumably at the CD changer).
A way to run a wire from those cables back to the dash or wherever you want to locate the iPod.
And of course you need that wire, ending in a stereo mini jack to plug into the iPod.
It's also good to have some way to mount the iPod so you can control it from the driver's seat. I use the Monster iSportCase, which I found to work really well as a dashboard mount.

My Boxster is a '98 with the CR-210 in-dash cassette player and trunk-mounted 6-disc CD changer option. Depending on model year and audio options, your system may have different connections that mine.

Accessing the Input Cables


accessing the CD changer bracket	making the stereo RCA jacks available

First I undid the two screws that hold the CD changer mounting bracket to the front trunk wall. This allowed the CD changer to be pulled out on the mounting bracket and made it easier to access the cabling that ran to the CD changer. But now that I know where that cabling is, I could have managed to access it without detaching the bracket.

The Sony/Becker CD changer cable on the Boxster runs from the head unit in the dashboard, through the firewall, and into the front trunk compartment. It splits into a control cable and an analog stereo audio cable. The control cable has some kind of multi-pin DIN connector plug. The audio portion ends in a regular stereo pair of RCA plugs. A short adapter cable protruding from the CD changer connects to these three plugs. I disconnected the audio cables and re-mounted the CD changer with the RCA plugs hanging next to the CD changer so that I could hook them up to my own cabling next.

iPod Audio Cabling


feeding the audio cable under the dash and out the door jamb	connecting to the original RCA plugs, before tucking them under the bracket

I scrounged around in my bins of audio cables and adapters and found a suitable RCA-to-mini-stereo adapter, a couple of RCA couplers, and a long enough stereo RCA cable (9' was more than enough). Of course, you can get any of this at Radio Shack for a few bucks. If your CD changer cabling is like mine, you need something that starts with a mini stereo plug (to plug into the iPod headphone jack) and ends up in a pair of RCA jacks (for the existing stereo RCA cable to plug into).

I started at the dash with the mini stereo plug, and ran the cable into the passenger side footwell. There's a perfect gap under the dash there where you can run a cable tucked out of sight.

The cable then feeds out the door jamb and into the under the front trunk lid. Then it goes under the plastic cowling and into the front trunk comparment.

Hooking it Up


barely visible once the wires are tucked away	dash mount holder bracket

Finally, the stereo RCA cable plugs into the factory-installed stereo RCA plugs with a pair of RCA couplers. If you have an RCA cable that ends in jacks instead of plugs, this is not necessary. Any excess cable can be tucked under or behind the CD changer mounting bracket.

I found a good, inexpensive dashboard mount for the iPod: The Monster iSportCase. (There are different models depending on the iPod size, thicker or thinner.) It's a plastic case that covers the back the iPod completely, wraps around the top and bottom (with slots for all connectors), and leaves the front face completely open for operating. On the back is a belt clip, and it comes with a black plastic loop that can be mounted to the dashboard unobtrusively. Double-stick tape did not seem strong enough to me, so I zip-tied the clip to one segment a 1-inch long L-shaped metal bracket, and wedged the other segment between the two storage bins in the console. It's a snug fit and the mount is safe and solid, and puts the iPod within easy reach for control.

You'll have to keep a placeholder CD in the changer so that the head unit sees that it is "playing" something. The display will show the CD and track number that the changer is playing, even though the audio is coming from the iPod. One little glitch is that when the placeholder CD reaches its end and resets back to track 1, the head unit output is muted for a few seconds.

Reader Guy Kuo reports that he was able to disconnect the DIN connector and the head unit treated the iPod as an auxiliary input. But on the CR-210 once you disconnect the DIN connector, you cannot select the CD changer and therefore cannot select the iPod as an audio source. The DIN-aux trick may be specific to units with an aux in capability (the 220 series). For these units, Becker also sells a kit with an adaptor cable and tools for under $20 that lets you hook up an external sound source such as the iPod to the aux in, and you can select it on-screen after enabling aux in via the TP menu. (Part number 1319.116-276 from the Becker parts department at (888) 423-3537 x1209.)

Well, that's it. When you select the CD changer as the source for the car stereo, you'll hear whatever is playing on the iPod. You control track selection on the iPod. Voila, your entire CD collection is now in your car, instead of just 6 CDs or whatever. And because it's hardwired, it sounds great.

Thanks to Kevin C. on the Boxster Board for suggesting the CD changer direct connect method.