How can I tell if my computer's audio input is in stereo?

About a year ago I was trying to record music onto my hard drive from a stereo source. Someone here suggested getting some adaptors to go from two RCA plugs to my computer’s mic input, and capturing with Audacity software. That worked great, except I was only getting the left channel. That suggested to me that the input was mono. Screw it, I said, I need to get a new computer one of these days anyway.

Fast forward to a year later. I got a new computer. So last night I was trying it again, and it seems – though I’m not sure – that I’m getting both left and right channels, but both panned to the middle. It could very well be that I don’t quite understand Audacity well enough, but it could also be that the input jack is mono, or that there’s some setting in Windows that I need to make.

Any ideas?

FWIW, Dell Inspiron laptop and Windows 7.

a stereo adapter would have 2 RCA sockets and a coaxial plug with 3 conductors (tip, ring, sleeve).

Your mic input will be wildly overloaded by a line level output which will yield crappy, distorted sound regardless of the mono-stereo issue. There are lots of cheap USB mixers for PCs that would be much better solutions for your desired transfer.

Good point about overloading the input, though it seems I only have to turn down the master volume on my mixer to about 5 to stop clipping.

I had no idea there were such things as USB mixers. The cheapest I found was $52 and they go way up from there. Even the cheap ones are way overkill for what I want. Wouldn’t a simple RCA to USB adaptor do that same thing?

Can you vary the balance Left/Right on your source? That should vary your recording in Audacity.

Also, doesn’t Audacity show the sound on the right and left channels as a sort of graph? If so, do the left and right channels differ? If they differ you are recording stereo.

If all else fails a Beatles song like “Getting Better” of Sgt. Pepper’s should have pretty clear stereo separation, guitar on one side and and vocals on the other side.

Since I’m sending from a mixing board, I can absolutely pan things wherever I like. But even having things hard panned, it sounded like they were centered.

As far as Audacity goes, when I start a new recording, it opens a new mono track instead of using the stereo one I specified for it. I’m not sure how to force it to use the one I want yet. But I’m wondering if the new one it opens is mono because that’s what it detects.

I don’t have Audacity here, but according to the manual it should be in Preferences, Audio I/O:

Are you using the Mic input or a Aux or Line-In? I’d use Aux or Line-In. The Mic port could be mono, since it would usually be used for those simple $2 headset mics. But really most everything I’ve seen on PCs since DOS and SoundBlaster days has been stereo.

And I assume your adapter/cables are stereo? This diagram will show you a mono vs stereo plug: Notice the 2 rings on the stereo plug.

My adaptor and plugs are definitely stereo.

There is no aux input on my computer. I’m starting to think that USB is the way to go.