Logic Part 2 - Creating a Paging Matrix

Will Fraser

Logic Part 2 - Creating a Paging Matrix

This design has a number of unique features including:
~ Single paging station using Push To Talk [PTT] microphone
~ 12 button keypad for zone selection
~ LED status feedback for operator
~ Scalable design from 001 – 999 zones

In this design we will discuss creating a Paging Matrix that can be controlled with just a PTT Microphone and a 12 button keypad connected to Soundweb London control ports. The included design is 100 zones but can easily be scaled up to 999 zones as needed.

This design is based around the BLU-800 so that it can be scaled to 999 output zones. If your project requires less zones, a BLU-160 or even a BLU-100 could be utilized instead.

The audio configuration is very straight forward. There are some standard dynamics processing for tuning the microphone for maximum intelligibility, and a gain point for mute and level control. This feeds a Matrix Router that is controlled via Parameter Presets to route the page microphone to the desired output. The Multicast Cobranet bundle is used to send the page signal to additional BLU-800’s when creating a system with more zones.

A single output Crossover is on each output to provide a gain & mute point as well as some High and Low pass filters commonly required in distributed audio systems. If you are creating a smaller system you may be able to add additional processing such as output EQ as DSP resources are freed up.

The key to this design is really in the Logic circuit. The circuit needs to accomplish several tasks; Store three consecutive momentary decimal inputs to create a value of 001 - 999, recall the numbered parameter preset based on a defined trigger [the # key] to change the microphone router, reset the router upon releasing the PTT switch on the microphone.

From the keypad, Buttons 0 – 9 and # are connected to the Soundweb London control inputs. The Microphone PTT switch is connected to the last remaining control input. These Control Inputs are assigned to 12 logic Sources within the Logic Configuration as direct action. This means as the control input goes high [switch closed] the Logic source will also go high.

The first action of the operator is to unlock the circuit by pressing the PTT switch on the microphone. This is run through a Logic Not to invert the signal. This sets the Reset [R] on all the Counter Triggers low and unmutes the paging microphone. This is done through a Logic Link between the Logic End and the Mute button in the Gain object.

The second part of the logic circuit is the counter. There are several was to create a count within logic, for this example four individual Counter Triggers works best. The Counter Triggers are used to control the Logic Snapshots that are storing the numbers in the order they are pressed. Each Counter has its count property set to its position in the count; the first one is 1, the second is 2 and so on. A Logic Or sums the outputs of the 0 – 9 and # Logic Sources and is fed to each Counter Trigger. Every time a button is pressed it will drive the input on the counters. The outputs from the four counters are used to control the Store and Recall [R] inputs on the three Snapshot objects as the count progresses.

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