iPod in car via FM modulator

Factual Questions
1

The other day I had an FM modulator installed in my car, so that I can play my iPod through my car stereo speakers. Basically, the modulator goes inline to the car’s antenna and modulates the signal it receives from the iPod into an FM frequency signal. The modulator plugs into the iPod’s headphone jack.

Query: What should I set the iPod’s volume to when I’m using it in this manner? Full, so that it outputs the maximum power? Low, so it’s a fairly weak signal that the car stereo then amplifies? Or somewhere in between?

2

I did this with a Rio PMP 300 back when I still had it.

It depends on the iPod’s volume control, you have to adjust it by ear. I would guess that the proper setting would be “somewhere in between”. My car stereo has a volume shown numerically from 0 to 40. Usually when I listen to the radio driving around town the volume is 16-22, maybe as high as 24 if I’m really blasting a song. So I set the car stereo to 20, plugged in the PMP300 and started it playing. Then I would adjust the PMP’s volume so that the sound level coming out of the radio as closely matched the sound level I would get if it was a real radio station and not one coming in from the modulator.

If the iPod has a numeric volume display, remember the number you settle on. I think the sweet spot for the Rio PMP300 in my car was “12”.

If you set the iPod’s volume too high, the sound is going to be clipped off, distorted, and sound terrible. Too low and you might get hum from the car’s amplifier when you turn it up very high to be able to hear the iPod. And there’s also the risk you’ll accidentally tune the radio off the FM modulator to a real station and be unpleasantly surprised by how loud it is.

Just thought of something else… I haven’t looked up the iPod’s specs, but some mp3-playing devices have a “LINE OUT” jack as well as the Headphone one. Line Out gives a signal level good for plugging into red/white RCA jacks at the back of a home stereo, and this might be optimal for your FM Modulator. If you have one, try that first and you won’t need to fiddle with the iPod volume at all.

3

You’ll see somewhat longer battery life if you set the ipod’s volume low, rather than on full.

In practice, just turn it to yield about the same volume as an off-air radio station.

4

The new iPods that came out this week (Monday?) have line out capability using the docking connector at the bottom.

5

Set it fairly low, otherwise it may clip and sound terrible.

6

Thanks for all the great responses!

I had one of the second generation 10gb iPods, and upgraded it to one of the new 30gb models using CompUSA’s TAP extended warranty.

So, my new one has the dock with the line out. It’s still a standard mini-jack, so I figured it was really just a headphone plug mislabeled. I’ll try it using the built in headphone jack and the lineout in the dock, and see how they sound.

7

Could I do something like this with my computer and hook it up to a stereo in the basement? (Two floors below)

8

The range on these things is fairly limited, under FCC restrictions. There are other wireless audio/video senders for getting an audio signal from one part of your house to another, using either 900MHz or 1.2 GHz that you might want to look into.

9

Just for the record, what I installed doesn’t broadcast the FM signal. It actually hooks inline into the antenna cable.

I’ve heard the little broadcasters you can get don’t work too well, especially if there’s a strong signal at the frequency you’re broadcasting on.

10

Such as what? Where could I buy one of these things and how much should I be expecting to pay?