Music Mix

I have a Sirius satellite radio that I listen to quite a bit. I listen to it most while I am at work. Normally I wear a set of headphones so I don't disturb my coworkers with my music. Unfortunately, I can't listen to the radio and my laptop at the same time. Some of the alerts on my laptop have useful audio, and I'd like to hear those. My Dell Inspiron 8500 has a flaw: it does not have a line-in jack. I was kind of bewildered by this when I first noticed that it was gone. Nearly all sound cards have three or four jacks: headphone out, mic in, line-in, line-out. If I had those jacks, I could simply route the radio to the line-in and listen to both. Unfortunately, my laptop only has a mic in. The mic in is a mono (as opposed to stereo) line. It doesn't work very well either. I really don't want to ruin the quality of my music, so I was looking for another way to combine these two sources

Last night, I was browsing through Best Buy, when I saw a minijack Y-adapter. It was intended to allow two sets of headphones to listen to a single radio. I thought, "Hey, this should work the other way too, right?" My electrical engineering knowledge piped up with a little reservation though: using it the other way will result in two sources driving current on a line at the same time. This is a bad thing, but hopefully the smart folks at Dell and Altec Lansing (the makers of my speakers) were smart enough to foresee some foolish person mangling their equipment in this way. Plus, the Y-adapter was only five bucks, which is much less than the hundreds of dollars for a studio mixer.

I got into work today, and to my dismay, my worries were affirmed. Neither the radio nor the laptop have a line conditioned output with enough impedence. The result is that I have to turn the volume way up on the radio to hear it at all. Doing this is bad, as it is driving too much power on the line against the laptop sound card. I don't have much faith in the quality of the laptop sound card, so I'm not going to stress it out like that. I suppose I could grab a couple of connectors and resistors and fashion my own, simple mixer. That might be a fun weekend project.

So, for now, I just leave the laptop volume turned up enough that I can hear it over my headphones. It only dings every once in a while, so I'm not aggravating my cube-mates too much. And I can still listen to the radio in full, high quality, stereo sound.