4 Operation
The IQ–AMB-5 and IQ–SMX-6 sensing mixer/multi- plexers are IQ components that can be controlled and monitored from a remote location via an IQ System. In addition to basic mixing functions, the IQ–AMB-5 and IQ–SMX-6 sensing mixer/multiplex- ers offer advanced signal processing and have the capability of mixing audio signals automatically. The IQ–SMX-6 is a 6x2 automatic mixer, with computer controlled input switching and routing capabilities. The IQ–AMB-5 features many of the same automatic functions as the IQ–SMX-6,with the added ability to sense and compensate for ambient noise levels. The IQ–AMB-5 operates as a 5x1 automatic mixer with the sixth input reserved for ambient level sens- ing. In addition, it operates as a passive 6x1 mixer that is output independently to channel 2, ideal for monitoring purposes. Both models can be inte- grated with other like units to form larger composite mixers.
The following sections describe the IQ–AMB-5 and IQ–SMX-6 features and their operation. Where specified, some features are accessed via controls located on the unit itself; however, most of the fea- tures are configured and controlled using IQ soft- ware. Please contact your Crown representative or Crown's Technical Support Group if you are unfamil- iar with IQ software.
4.1 Hardware
4.1.1 IQ Address Switch
A8-segment DIP switch is used to set the IQ ad- dress of the unit. The unit must be given a unique IQ address so it can be independently controlled and monitored by the system. It must also be set prop- erly if an IQ–SMX-6 is to be used in a Crown Local Net. Two or more IQ components should NEVER have the same address on the same Crown Bus loop. See section 3.2.1 for more information about setting the IQ address. Important: The IQ address should only be set with the power cord discon- nected from the AC supply.
4.1.2 Baud Rate and Parity Switch
A 6-section DIP switch is used to set the baud rate and parity for RS232 serial communication. This is only necessary when the unit is to serve as system interface. Important: The baud rate should only be set with the power cord disconnected from the AC supply.
4.1.3 Enable Indicator
The front panel Enable indicator lights up to show that the unit is plugged in and AC power is being supplied.
4.1.4 DATA Indicator
The front panel DATA indicator lights up to show that digital information is being received by the internal processor from an external source (Crown Bus or serial computer port). A DATA indicator also ap- pears in IQ software, and can be forced to remain lit as a helpful diagnostic tool.
4.1.5 Main Audio Inputs
Three-terminal removable barrier block connectors are provided for the audio inputs. Each input has a three-position M/L/P selector switch for mic level, line level, or mic level with +44 VDC phantom power. Select the left position (M) for microphone signal levels up to +7 dBu (o dBu = 0.775 volts). Select the center position (L) for line level signals up to +32 dBu. Select the right position (P) to provide 44 VDC to mics requiring phantom power.
4.1.6 Sense Input (IQ–AMB-5 only)
The IQ–AMB-5 has a Sense input in place of one of the Main inputs. This input is identical in all respects to a Main input, except for the internal routing of the audio after the gain stages. The Sense input does not enter the output channel 1 mix, although it can enter the output channel 2 mix (as a sixth main input). The sense input is used to “sense” ambient noise levels through a connected microphone. The IQ–AMB-5 uses this signal to automatically adjust other input levels to compensate for changes in ambient noise level.
4.1.7 Main Audio Outputs
a3-pin removable barrier block plug is used to connect to the main output of each channel. These outputs can also be connected to the stack inputs of other mixer/multiplexers to make a larger mixer.
4.1.8 Bus Outputs
A3-pin removable barrier block plug is used to connect to the bus audio output of each channel. The bus outputs are isolated switchable outputs that can be turned on when needed by the IQ System. This allows many multiplexers to be tied together on the same bus without loading down the outputs.
4.1.9 Stack Audio Inputs
Two unbalanced stack inputs are provided (one per
