not able to record?

I am not sure this is the recommended way, but it worked for me (v 24.0.0.46)

Pulling up Edit>Preferences>Audio Hardware I have only 3 options under MME (Line-in, Mic, No Input) obviously none of these is “What u Hear”. Switch from MME to WASAPI. Select “HD Audio driver for Display audio” and click on Settings. Select Recording tab. Options now are Line-in, Mic and Stereo Mix (that’s Adobe-speak for Creative’s “What u Hear”). Click Stereo Mix, set as default, then click Properties and click “Enable this device” from the drop-down list. Exit back up again and switch from WASAPI back to MME. You will see Stereo Mix as an option now, select it. In the Stereo Mix Properties, there is a tab for Levels, make sure that is set to 100%. 

That should fix it.

The record level settings on your sound device control the input levels to Audition. Audition just records - very accurately - exactly what it's sent and has no control over the levels at all.