Problem with Line in in Ubuntu dual boot iMac

[rmcellig]

I already have a couple of posts about this in Ubuntu and Linux forums but I was hoping someone can help me here. I am using an iMac with Ubuntu 10.04. I am unable to record anything through Line In. I can record from the internal mic on the iMac but line in doesn't work. Any ideas as to what I should do? If you need any more info, let me know. Thanks!!!!

[kozikowski]

Can you boot it into OS-X and does that work? You have a violation of a basic rule in a company I used to work for that used highly modified equipment. "Did it work before you messed with it?"

Koz

[rmcellig]

Yes. In OS X, no problem, I can record programs from the radio. Works fine. When I boot into Ubuntu, doesn't work at all. The internal mic on the imac works. I can record from there but not line in.

[steve]

In OS X, no problem, I can record programs from the radio. Works fine.

Then this is clearly a Linux specific problem - I'll move the topic to the Linux section.

When I boot into Ubuntu, doesn't work at all.

You mean that recording from the "Line in" does not work in Ubuntu but recording from other sources does work in Ubuntu?

[rmcellig]

Yes. Recording from the built in mic on the iMac works fine but recording from Line In doesn't. All I get is white noise when recording. When I boot into the Mac partition, Line In recordings work fine.

[kozikowski]

Oh! Magic words! You're recording the wrong one. The "Line-In" on a modern Mac is High Level Analog Stereo and S/PDIF Optical Digital.

Same connector.

Koz

[rmcellig]

What does that mean and what should I do in Ubuntu to get it working if possible.

[kozikowski]

It means if you walk up to your iMac with an 1/8" stereo analog audio cable, the machine will use the analog pathways to the internal digital converters to produce the show. If you walk up to the same connection with an Optical Digital Toslink fiber cable, you can send and receive digital audio services like 5.1 surround, etc.

I have no idea how to set up linux to drive that system, but if the other services work, that's the most likely problem. That connector is not normal as in a Windows sound card.

Koz

[steve]

Recording from the built in mic on the iMac works fine but recording from Line In doesn't.

How are you switching from mic to line?

[rmcellig]

Yes. In the Sound preferences there is an option to select line in, microphone 1 or microphone 2.