Alesis Wedge Reference Manual page 27

Chapter 2 – Connections
you do not hear any audio after making these connections, swap the input and
output cables at the Wedge, as these may be wired backwards. If the cable is color-
coded, usually the red jack represents the send (which connects to the Wedge's
input) and black is the return (which connects to the output).
Stereo. If a stereo instrument (such as a keyboard or sampler) is con-nected to two
separate channels of a mixing console, you will need two 1/4" TRS cables, one for each
channel. The connection is made in a similar fashion as described above. This hookup
is especially useful for adding ambience with the Stereo Room configuration.
24 Wedge Reference Manual