How to Set Up a Church Sound System

Four measurements decide most of the system, and none of them require a consultant. Width at the widest seating row, depth from the front edge of the platform to the back row, ceiling height at the highest point over the seating, and the distance from where the loudspeakers will hang to the furthest seat. That last one is the throw distance, and it is the number that sets amplifier power.

Write them down, because every later decision references them. The throw distance sets watts. The seating width at the throw distance sets the loudspeaker coverage pattern you need. The ceiling height decides whether loudspeakers can be flown at all, and the room volume decides how reverberant the space will be, which is covered at reverberation time for churches.

The second thing to establish is service style, because it changes the answer more than seat count does. The target average level at the mix position for a speech only service is about 75 dBA, a traditional hymns and organ service about 82 dBA, a blended service with piano and a small band about 88 dBA, and a contemporary worship band about 95 dBA. Those seven decibels between blended and contemporary are a factor of five in amplifier power for the same room, which is why two churches with identical seat counts can need genuinely different systems.

These are the figures the calculators produce for four common room sizes at a blended service level, using a 96 dB sensitivity loudspeaker and 12 dB of peak headroom.

Wattage is the easy number and the less important one. What decides whether a congregation can understand the preaching is whether the loudspeaker pattern covers the seats and stays off the walls and ceiling. In a reverberant sanctuary, energy that misses the seats does not disappear, it comes back as reverberation that smears every consonant.

Work out the horizontal pattern you need from your seating width and throw distance. A 90 degree horn covers about 80 feet of width at 40 feet of throw; a 75 degree horn covers about 61 feet at the same distance. A wide fan-shaped room needs the wider pattern, a long narrow room needs the narrower one, and getting this backwards is the most common loudspeaker mistake in a church. The speaker coverage calculator does the arithmetic, and how to aim and place church speakers covers the aiming.

Two other decisions follow. Powered or passive: powered loudspeakers such as the QSC K12.2 at $899.99 put the amplifier in the box and suit a portable or simple installation, while passive boxes with a rack amplifier suit a permanent install where the amplifiers live in a closet. That trade is at powered versus passive speakers. And whether you need a subwoofer, which for speech and a blended service is usually no, and for a contemporary band is almost always yes. Check with the subwoofer sizing calculator.

A console is sized by its input list and nothing else. Count every source: each vocal microphone, each instrument, the pulpit and lectern, the choir microphones, playback, and the feed from the livestream computer if it returns audio. Stereo sources such as a keyboard count as two channels, not one, and this is where churches most often under-count.

Then add a growth margin of about 25 percent and round up to a size that is actually sold, which means 16, 24, 32 or 40 channels. A console with no spare channels is a console you replace in two years, and the marginal cost of the next size up at purchase is always less than the cost of replacing the desk. Our worked 250 seat room has 16 inputs, which with growth lands on a 24 channel console. The mixer channel calculator builds the list for you, and how to choose a church mixing console covers digital versus analog.

Three mistakes account for most disappointing church systems. The first is buying the console first, because it is the visible, exciting purchase, and discovering the loudspeaker budget has gone. Loudspeakers and their amplification set the ceiling on everything downstream; a superb desk cannot make an inadequate loudspeaker cover the back row.

The second is ignoring the room. A sanctuary with a long reverberation time will defeat any system, and no amount of equipment fixes it. If speech is unintelligible at the back, the problem may be acoustic rather than electronic, and the money belongs in acoustic treatment rather than in more watts. Check the target for your service style with the acoustic treatment calculator.

The third is forgetting the unglamorous lines. Cable, racks, stands, power and rigging are about 10 percent of an audio budget and are always the first thing cut, which is how a church ends up with excellent loudspeakers on a floor covered in adapters. Budget them at the start, using building a church AV budget and the AV budget allocator.