Yamaha DTXpress/DTXplorer/DTXtreme

Getting the kick pedal to work is actually rather simple. Just get a
stereo to mono plug and plug it into the rock band kit, from there
plug a stereo cable from that into the output in the DTXpress brain
where you would plug headphones in. Then plug a stereo cable from the
bass pedal to the DTXpress brain and set the switch in the back to
MAC, done! Enjoy =).