Yes, the DUAL CUBE LX allows you to input both the guitar and microphone simultaneously (using a headset microphone). To connect, please plug your guitar into the GUITAR jack and the microphone into the PHONES/REC OUT jack.
The pin configuration for the PHONES/REC OUT jack is as follows, using a TRRS connection:
Note that the signal input from the headset microphone does not pass through the PRE AMP, EQ, EFFECTS, DELAY, REVERB, or LOOPER. Please refer to the following block diagram.