The podDI from Whirlwind is a single-output summing direct box that can be used to connect CD and MP3 players, computer sound card outputs, DJ mixers, etc. to professional equipment with balanced inputs such as a mixing console. The unit can also be used as a high-quality, single input passive DI box.
The personal audio interface accepts a stereo input and sums them into a single mono output. A variable attenuator on each input provides level matching between left and right inputs, allowing the podDI to also function as a passive mixer in split track audio applications. So for instance, a voice track and a music track can be balanced to the summed mono output.