Thanks for your help! The headphones plug directly into my laptop using a standard 1/8 inch phono jack. It might plug into the sound card but I'm not sure. I haven't added any hardware, so it's whatever the factory standard is for laptop audio jacks. Every audio source (streaming media, stored audio, system sounds) defaults to the laptop speakers when the headphones aren't plugged in, but all audio goes through the headphones if they are plugged in. But I'm finding that Cakewalk is very persnickety in that the headphones have to be plugged in when starting the app or they won't work. I already knew this, but I didn't know that if you saved a project in that scenario, it changes some setting so you can't use the headphones at all.