The best replacement for stereo mix is channel grouped.

The best alternatives to stereo mix are rated as following:
★★★★★  channel grouped
★★★  line in
★★★  mono mix

Your alternative for stereo mix is not listed? Suggest!
Speaking about stereo mix, one probably shouldn't forget about usb mic.

Other search terms related to stereo mix and their ratings are:
★★★★★ usb mic
★★★ audacity
★★ sound recorder
★ microphone skype
★ realtek
★ sound card
★ sigmatel
You have in mind a companion for stereo mix and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of stereo mix in all years. Click on graph for more.
stereo mix
channel grouped
line in