9
8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
The input control point labeled “Rear Panel”represents the gain adjustments which can be made from the rear panel
programmable inputs. The rear panel gain control is attenuation only, starting at a maximum gain of 0dB. The rear
panel input gain controls may be limited in their adjustment range using the Remote Input/Output Level Limits tab on
the AM8/4 control panel. In addition, you may set a rear panel preset gain value that will be applied to any outputs
which are being controlled by a programmable input. The preset gain is applied at power up. Note that if there are
no limits applied to the rear panel gain range, the input channel may be turned completely off. The current gain value
of the rear panel controls is displayed on the Remote Input/Output Level Limits tab.
The output gain structure is identical to the input gain structure. The Output Gain range adjustment is +15dB to -
63dB plus off. The output gain is adjusted using the Output Gain tab. Rear panel output gain control ranges may be
set in a similar fashion to the input control ranges in the Remote Input/Output Level Limits tab.
Matrix crosspoint gain can be set using the Matrix tab. Input-to-output gains are set based on the requirements of
the application. For example, you can set up a “mix-minus”sound reinforcement system when you are using multiple
microphones and overhead distributed speakers. Each speaker (or small group of speakers) would be fed from its
own mix of microphones. A given speaker’s mix would consist of all microphones not physically close to the speaker,
while excluding those microphones which are close to the speaker. The possibility of feedback is greatly reduced
when this approach is repeated with all system speakers. A multichannel amplifier (like the Lectrosonics PA8) may
be used to power each speaker individually.
Programmable inputs and outputs may be set up using the Programmable Input/Output tab. Below is a short list of
typical applications for each of the programmable input functions available:
Analog In Control: Used to control the input gain of one or more inputs with a potentiometer or DC
voltage source. Additionally, a toggle switch can be used as a mute switch by shorting the program-
mable input to ground for mute.
Increase In 1dB, Decrease In 1dB: Used to control the input gain of one or more inputs with
momentary switch closures. Each switch closure will increase or decrease the gain of the associ-
ated input(s) by 1dB. If the switch is pushed and held, it will continue to increment or decrement until
the switch is released or the gain reaches its high or low limit.
Analog Out Control: Used to control the output gain of one or more outputs with a potentiometer or
DC voltage source. Additionally, a toggle switch can be used as a mute switch by shorting the
programmable input to ground for mute.
Increase Out 1dB, Decrease Out 1dB: Used to control the output gain of one or more inputs with
momentary switch closures. Each switch closure will increase or decrease the gain of the associ-
ated input(s) by 1dB. If the switch is pushed and held, it will continue to increment or decrement until
the switch is released or the gain reaches its high or low limit.
Memory Preset: Used to recall one of the 15 AM8/4 preset memories with a momentary switch
closure. Remember to save the same memory preset associations in all the AM8/4 memory preset
positions you’ll be using. You can also assign a programmable output to reflect the programmable
input state of the programmable inputs you’re using for memory preset recall to drive LEDs for visual
feedback of the current memory preset.
Toggle Crosspoint Gain: Used to temporarily apply the signal from any one of the 16 inputs to any
combination of outputs using a momentary switch closure to toggle the state of the affected
crosspoints. Useful for zone paging applications, etc.
Mute In: Used to mute one or more inputs with a switch closure. Subsequent contact closures
toggle between mute and unmute. You can also assign a programmable output to reflect the pro-
grammable input state of the programmable inputs you’re using for input muting to drive LEDs for
visual feedback of the mute/unmute state of the inputs.
Mute Out: Used to mute one or more outputs with a switch closure. Subsequent contact closures
toggle between mute and unmute. You can also assign a programmable output to reflect the pro-
grammable input state of the programmable inputs you’re using for output muting to drive LEDs for
visual feedback of the mute/unmute state of the outputs.
