10
Mix-Minus Explanations
Why do I need a Mix-Minus Setup?
Mix-minus is an audio signal that is designed to avoid feedback and
echo in a conference or telephone interface application. When connect-
ing a phone hybrid to a mixing console, the caller’s audio will be con-
nected to an input channel on the mixer along with all the microphones,
music, etc. All of these inputs combine to create the Master mix to be
sent to your broadcast, recording device, or the speakers of your PA
system. However, if you connect this Master mix to the input of the hy-
brid, you are also sending the caller’s own audio back to the caller.
This completes a feedback loop and creates a strange and annoying
echo. That is why it is important to create a special mix that contains a
mix of all the microphones, music, etc., “Minus” the caller’s audio.
Wireless Phone Interface
Audio Mixer
PA System,
Broadcast,
Podcast, etc.
Mix Plus Caller
Mix Minus Caller
Which Mix-Minus Setup Should I Use?
Most radio stations and recording studios should use the Studio Setup
shown on pages 8-9. Using an Aux Send output that is Post Fader will
keep the audio that is being sent out to the caller tied to the same out-
put you send to your broadcast or PA system. This way your sound
engineer can more easily control each channel. During a station break,
the talent microphones can be muted simply by turning off the output
level knob or slider and their audio will not be sent to the broadcast or
to the caller.
If you have a small studio and you use your wireless phone hybrid to
record interviews, you might consider using the Simple Setup on page
11. When the Aux Send output is Pre Fader, the levels you set on the
Aux Send controls will only affect what the Caller hears, and the levels
you set at the output faders will only affect the recording or broadcast.
If the talent wants to be able to talk to the caller during station breaks,
this is the setup you should use, although the talent would need to con-
nect their headphones to the hybrid instead of to the mixer. You should
also use this setup if you want to be able to send music or sound ef-
fects to the broadcast that the caller will not hear.
