Zoning Out

Unless your venue is a small coffee shop, with a half a dozen tables in the same room, it's unlikely that there is a single sound system that can adequately meet your needs. Even with a coffee shop, as soon as you put a couple of tables in a different room, or on the pavement outside the shop, your sound system needs to be able to provide sound at different levels and possibly even different programme material to each acoustic zone.

During any given day, the chances are that your sound level and programme requirements will vary significantly, as the tempo of your business varies and the pattern of usage of the different spaces within your venue changes. Background music during the afternoon may change to television audio, a quiz night, a DJ, a live act or Karaoke during the evening, and move on later to music videos, a jukebox or quiet grooves to chill out to. Even if your programme material doesn't change through the day, you will probably find that some patrons will be looking for quiet zones to conduct business or personal conversations in, whilst others will be happy with the loud social buzz of conversations shouted over The Best of The Clash, on continuous repeat.

Traditional approaches to meeting these demands in a sound system, have included separate amplifiers, each with its own volume control, for every zone. Alternatively a completely separate sound system was provided for each area, with a signal distribution system used to share sound sources such as satellite audio, background music systems, emergency evacuation warnings and announcement microphones.

Those who could afford the technology, and the time required to learn their operation, installed matrix controllers. Like a specialist mixing console, with an input from every sound source and an output for every zone, these devices offered the ultimate in flexibility, despite being a somewhat daunting machine to drive.

The advent of the low cost Digital Signal Processor (DSP) chip, which can mathematically emulate the multitude of costly mixing circuits required in a matrix controller, has made matrix controllers both affordable and straight forward to operate. Of course once you give an audio equipment designer a DSP chip to play with, they will keep adding clever functions until the chip is brought to a standstill. Then, because the DSP chips are cheap, they'll throw in a couple more. And, as network interface chips now also cost very little, they added an Ethernet port and made the controllers programmable through an ordinary PC, instead of morass of knobs and switches. Thus was born the new generation of highly sophisticated matrix or zone controllers.

The basic matrix functions of zone control systems enable you to send a different mix of any of your sound sources (background music, CD, DVD, TV, satellite, radio, karaoke, VCR, live act, DJ/VJ, Internet, juke box, MP3, microphone, etc) to each acoustic zone in your venue. Mix levels can be set either from a panel on the zone control system or from a software package running on an office computer.

Different levels and sources may be preset for specific times of the day for each zone and stored for later recall. Depending on the sophistication of the zone controller and the options installed, changes to a different preset can be triggered either by an internal clock in the zone controller, sound levels in a particular zone, manual control from a computer, scheduling software in a computer or from local control points in the zones.

If for example, your bistro is scheduled to go to its evening settings at 7pm for the dinner trade, but a party of walk-ins appears at 6:45pm for dinner, the front of house staff could trigger the evening settings from the bookings computer at the waiters' station, by making a phone call to a manager's office, or by tapping on a touchpad mounted on a wall. These operations require no in-depth knowledge on the part of the bistro staff and can be limited or completely locked out if necessary.

One of the more useful additional features found in most zone control systems is the ability to make zoned announcements, paging calls and evacuation alerts. Announcements may be pre recorded or made from paging microphones around the venue. Most zone controllers have an automatic ducking capability, which fades the level of all other sound sources to a zone while an announcement is made, then fades them back up again at the end of the announcement. Paging zones, which can be set via a computer interface, may be allocated by time of day, point of origin, or the press of a specific key to trigger the announcement. Ducking levels and minim announcement volumes can usually be con figured for each zone and time of day, through a computer interface. If there's a corporate meeting being held in a function room, it may not be appropriate for them to be notified of the winner of the chook raffle or the readiness of Schnitzel number 87, but it would be important for them to be aware of a building evacuation or of a vehicle on fire in the car park.

Zone control systems are available from a wide range of companies in the audio business, with systems designed for everything from hifi audio and home theatre, to multi-building campuses, shopping centres and sporting complexes. Amongst the professional-quality installation systems, are offerings from Allen & Heath, Australian Monitor, BSS, dbx, Dynacord, Intelix, JBL, LA Audio, Matrix Audio, Rane, TOA and Xilica, to name but a few. Be sure to deal with a consultant who wants to get a good understanding of your needs before offering you advice about specific products, options and configurations.

by Andy Ciddor, © Copyright The Kilowatt Company