Specifiy amount of blending from stereo to mono?

I listen to ambient noise audio tracks to help me create white noise while studying.

Is there a way to specify a blend from stereo to mono?

The reason I ask is because with certain audio tracks, when in stereo, it’s too much at the ears and headphones, and when mixed into mono with Audacity, it’s right in the center of my brain. I’d like to be able to get a mix somewhere in the middle.

If not audacity, is there any way to control this?

There is an optional plugin called “Channel Mixer” that can do this. It includes a preset to “narrow the stereo” (which is what you want to do).
Download Channel Mixer from here: http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Channel_Mixer
Installation instructions: http://wiki.audacityteam.org/wiki/Download_Nyquist_Plugins#install