Taking it to eleven: Keys to killer live sound for churches

Posted: 27th February 2012 by Mezzanine Floor Studios in Live sound, Mixing Techniques

Anyone that has run live sound in church knows the inherent challenges all too well. Small churches with little budget for sound equipment often struggle to do an adequate job of supporting the contemporary sound of rock and gospel inspired worship music. Doing a great job is often beyond the expectations of most church staff, but it is possible with a little budget and a lot of know-how.

At my church we recently had a new A/V director come on board and we’ve worked to improve on the great foundation the previous A/V director had laid, improving the sound every step of the way. Here are some of the key things we’ve learned.

The biggest thing we’ve kept in mind: Intelligibility is the key.

Anything that draws people’s attention away from their purpose for being there, away from the presence of God, away from the words they are singing and what they mean is detrimental. So if people can’t understand the words being spoken or sung, we’re missing the point as sound engineers. This is obvious when it comes to the pastor’s microphone, but it is essential during the worship music as well.

Here are the things we’ve found that help intelligibility.

1. Roll off the low end on everything that doesn’t NEED it. Kick, Bass Guitar, and Floor Tom are a few of the instruments that do need it. Everything else just muddies it up. Use the high-pass or low-cut filter on your mixer, and if there is also a low frequency EQ, lower the level of that as well for channels that don’t need the low end.

2. Take out the low mids on channels that don’t need it. This is especially important for churches that meet in high school gyms, as the low mids tend to be very muddy and this adversely affects intelligibility.

3. Take the lows and low mids out of the monitors as much as possible. Anything with lots of low end that needs to be heard and has low energy can already be heard by the performers naturally (drums), through an amplifier (bass guitar), or through the PA since the low end of the sound spectrum is not directional.

4. If you have the chance to use subwoofers, do it. I’m not saying you should make your worship band sound like they are being played by your neighborhood high school kid with 10 subwoofers in his car. Rather, subwoofers enable you to get adequate low end without killing your main PA speakers to do it. Low frequencies at high volumes actually move the speaker cones enough to cause phase shifts in the mid range frequencies reproduced by the same speaker cone. This can make the mids sound hollow, adversely affecting intelligibility. Using subwoofers for your low end results in longer lasting, better sounding main PA speakers.

5. Use a crossover/delay processing unit before going to the amplifiers and speakers. This allows for a lot of control over the sound and enables awesome things like using an aux send to control the level of each channel that goes to the subwoofer(s) independently. Turning up the aux send feeding the subwoofer for the Kick, Floor Tom, and Bass in the choruses of a song, for instance, can enhance the dynamic range of the sound in a very musical way.

6. Compressing vocals is vital. Drum compression is often popular, but in most small church settings it’s not necessary. Since the drums are already the loudest thing happening, sound engineers in small churches really don’t need to augment the live drum sound much (if at all) in the PA, outside of maybe sending the Kick drum through the mains and subwoofer(s). Compressing vocals enables the engineer to spend less time trying to make sure a vocalist’s words can be understood, and more time enhancing the worship experience by building on the worship that is already happening on stage. Many vocalists talk much louder than they sing- compression means not having to worry so much when they go back and forth.

7. Use an aux send for reverb and return it to an open channel instead of an aux return (just remember not to turn up the aux send for reverb on that channel AT ALL!) By routing reverb this way you get a handy fader and mute button for the reverb signal, so you can easily mute the reverb when vocalists are speaking for a portion of the service, then bring it back in when they start to sing.

8. Make sure your vocalists understand basic mic technique and the way their microphone picks up sound. Nothing annoys the sound engineer and congregation more than a hapless vocalist that holds the mic at their navel and sings in a whisper. Having vocalists that cover part of the microphone’s capsule can cause the cardioid pattern in some mics to become omnidirectional because of the techniques used to make the microphone directional. Unless they are beat-boxing they should stay away from doing this. And, of course, they should know which end of the microphone to point at the monitor, and which end to NOT point at the monitor. It sounds elementary to sound engineers, but that is the level of knowledge some vocalists have about microphones, especially at church.

9. Gating/expansion is helpful for vocal mics too! Gating is popular with live sound engineers for drum mics, but it’s cousin, expansion, can be even more useful for vocal mics in many situations. If people use proper mic technique an expander on each vocal channel can help reduce the potential for feedback. Leaving mic channels “open” can be problematic, since increasing the number of “open” mic channels automatically decreases the gain the sound engineer has available to them before they induce feedback. Muting all mic channels that aren’t used for a particular moment counters that problem but makes it possible for the embarrassing “my mic is muted” moments to occur. Putting an expander on each mic channel and setting it properly can give the engineer the best of both worlds.

10. Use a spectral analyzer while running sound. This can be helpful with identifying feedback, fine-tuning channel EQ, or finding an annoying frequency. If you have a computer and a 2 channel interface for recording you can do this without an expensive hardware unit. Use the first recording channel to record what you want people to hear later (i.e. the sermon.) Use a mono out, tape out, matrix out, etc. from the board to do this. Use a headphone splitter on the headphone output of your mixing console and send one split to your headphones/monitors (duh) and the other to the computer’s second recording input. Drop a spectrum analyzer plugin on channel 2 in your recording software (BlueCat audio and Voxengo have free ones.) Now, whenever you solo an instrument you can see its signal in the spectrum analyzer.When nothing is solo’d you get a spectral picture of the whole mix from what the board sees. If you want to see a spectrum of the live sound and have a free channel on the board, turn down the fader and aux sends on that channel so it doesn’t get sent anywhere, then hook a room mic up to it. Most solo buttons on mixers are pre-fader levels, so you should still get sound from this room mic going to your board’s headphone output, and therefore to your spectral analyzer.

11. Be aware of your available power. Many churches weren’t wired for amplified sound. Oftentimes the people that know the actual routing of wires in the building are long gone, but it pays to find out. This will enable you to avoid having electrically noisy lights/dimmers plugged into the same circuits as your audio equipment. Also, if there are multiple sources of power onstage, make sure it’s obvious to the musicians which ones they should useĀ  for their instruments. Otherwise your perfect sound could be ruined by a ground hum loop just because the bass player got sloppy and plugged into the wrong circuit. Nothing kills intelligibility like a loud hum or buzz that’s not supposed to be there.

Peace,

Joshua

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