Paging Fundamentals: Ducking, Muting and More

Paging to a large area requires some sort of public address system.

It can be as simple as a background music system or as complex as a multi-zone processor. Often, those systems are already in place, and the proprietor simply wants to add paging capabilities.

In these cases, it's possible that business owners aren't aware of the improvements in background music and PA systems that have occurred since their original systems were installed, providing an upgrade opportunity.

Microphone Paging For Single Location Usage

Microphone paging makes sense in some instances.

If the page origination point is going to always be from a specified location, using a microphone makes sense. It's a logical solution, especially if you want to simplify the process for the end user.

You will want to make sure that the microphone has some sort of on and off switch so that the microphone is not always open. Frequently, paging microphones will have a "push to talk" button or bar that automatically shuts the microphone off at the release of the button.

Telephone Paging For Multiple Location Usage

Telephone paging is done most frequently in business applications where a phone system is in place.

Most phone systems have a paging port (or two) located on the system. To page, the user simply lifts the handset and hits the phone system specific code on the numeric keypad to send voice to that port.

The advantage of using a phone system for paging is that it allows multiple locations to act as page origination points; if a system uses a microphone for a page, the user must go to the microphone location to make the page.

If your phone system has a paging port, but the amplifier does not have a telephone input, an installer can place a level-matching transformer on the page line to convert it to a microphone level signal.

Ducking Identifies Priorities, Smooths Transitions

To ensure a smooth transition, some audio systems incorporate a feature called ducking, where the priority source comes through, while the default signal drops (or ducks) in level until the priority signal is completed.

After the page occurs, the volume of the default signal is brought back up over a brief period of time making for a smooth transition. Sound pressure laws still apply, whereby 3 dB of signal change is barely noticeable, and 10 dB of signal change appears to be about twice as loud.

A ducking level of 6- to 10-dB might make the most sense in the typical bar/restaurant or retail setting.

70-Volt Amps Deliver the Power

Most commercial audio systems use 70-volt amplifiers to deliver power because of reliability, adequate sound performance and ease of wiring.

A 70-volt system generally consists of

• a signal source
• an amplifier
• a speaker or series of speakers that have transformers attached to them

Those transformers take the 70-volt signal and convert it generally to an 8-ohm signal, which is then passed on to the speaker itself.