Whirlwind IMCOML Line Level Combiner - 2 in / 1 outUse the line level combiner when you want to create a mono mix from a stereo source but need to keep the original stereo signals isolated. It's great for feeding a DAT player or CD into a mono system or single channel on a board. This unit not only combines two line level signals into one line level output, it also compensates for the 6dB of gain that occurs when two in phase signals are combined. A handy ground lift switch breaks the shield