According to the LG Spectrum 2 (VS930) user guide, You can use the Volume Keys to adjust the ringer, media volumes, or the incall volume during a call. Or you can press both simultaneously to take a screen capture for the QuickMemo feature.
I found this from the LG Spectrum 2 (VS930), I have not test it yet. If anyone of you have test this, please share with me.
LG Spectrum 2 (VS930) device & button layouts
