Keeping Murphy at Bay

Mar 13, 2008 5:21 PM, By Karen Stackpole

THREE PRO ENGINEERS OFFER ADVICE ON HOW TO KEEP YOUR LIVE SOUND UNDER CONTROL

Equalization and Feedback

Place monitors and speakers carefully, keeping in mind where you have the mics set up in relation to them. The mains should go at the front of the stage facing into the house, and you should put the front row of mics behind the main speakers. Place monitors strategically on the floor, in front of and facing up toward the performers.

With mains, monitors, and open mics onstage, you're in potential feedback country. A graphic equalizer can combat this problem, and both Heller and Karr recommend adding one or two to your system (one for the monitors, another for the mains). But if extra gear isn't in your budget just yet, Heller offers the organic approach: "If the vocals are soft and you can't get them loud enough before you get feedback, then everyone should play down." See a pattern emerging here? Play dynamically. Listen. Establish a good acoustic balance.

A graphic equalizer in uneducated hands can be a disaster, though. Karr recommends learning to recognize the frequencies by routing a microphone signal through a 31-band graphic equalizer, then out to an amplifier hooked up to a monitor speaker. "Cautiously make the system feed back by nudging up the different frequencies one by one," he says. "Learn which notes are closest to that sound using a keyboard or guitar. When you learn the frequencies and figure out which ones are notoriously problematic, you'll be ahead of the game."

Every room has a resonant frequency or two that may cause problems in an amplified environment. "Get on a mic and just start making weird noises and turning up the gain," suggests Heller. "It'll start to feed back and you'll hear those resonances. Another thing a lot of guys do is play their CD and start pushing up frequencies on the equalizer, listening to what happens in the room. Certain things start to jump out or sound unnatural, and you can pull those frequencies down a little."

Both Karr and Heller warn that you should take a minimal approach with the graphic equalizer. "You have to be careful," says Heller. "You don't want to do a whole lot of radical stuff. Every time you turn a filter, you start introducing phase shift, and if you introduce more and more by doing tons of EQ, pretty soon the whole thing just sounds like crap." Karr also recommends a moderate approach. "Pull out what you need to pull out, but stop when you get to three or four frequencies," he says.

Getting Squeezed

Compression can often be a very effective tool, but it sounds horrible when it's overdone. Heller's recommended technique is conservative. "Just use it for a little bit of control-but don't make it sound like you're squeezing the life out of it," he says. "I'll use a compressor on vocals and horns; and a lot of times I'll use a limiter on a keyboard because they can be plinky sometimes, and things will jump out and hurt you a little." Lipnick uses compression for problems with dynamics. For instance, if he's working with a guitarist whose solo volume is high but whose rhythm volume isn't cutting through, he'll add compression to the guitar. This will bring up the general level so he won't have to ride the fader as much.

Heller recommends a general ratio of 2:1 to 6:1 with a threshold setting of 2 to 10 dB, but the setting you choose really depends on the instrument and how it acts, as well as the situation. "A little overall compression can also work really nicely sometimes," he says. "It can smooth things out and make the mix sound tighter."

On With the Show

Getting great sound for a live show depends on many different factors. The only predictable thing is unpredictability. But through preparation, cooperation with the sound engineer, and experience, you can easily circumvent or deal with these unpredictable aspects. Be aware of your acoustic balance onstage; you needn't play louder than God to achieve a rockin' show. Arrive on time, communicate your needs to the sound engineer, and trust him or her to handle the system.

If you do your own sound, spend time with your P.A. to understand its ins and outs thoroughly-before your gig. Learn the tones of the frequencies on your graphic equalizer so that you can more readily recognize problems with room resonance or the hot spots on a mic and can quickly notch out the offending frequency. Experiment with mild compression on your mix and explore the range of what your system can handle. Play around with reverb and effects if you want to add some texture to your sound. Indoctrinate a willing person who can listen in the house and help you mix your show. With an understanding of your gear, some commonsense preparation, and a good attitude, you can introduce Murphy to the bouncer.

When working with the house sound engineer, follow this protocol:

1. Arrive early for a sound check.
2. Provide a basic stage plot and input list.
3. Provide a set list with information on instrument changes, dynamic shifts, and so on.
4. Provide a basic outline of what you need in the monitors.
5. Come prepared with extra cables, fuses, batteries, strings, a drum key, and the like.
6. Be cooperative.
7. Remember that loud isn't necessarily good. Work on your onstage acoustic balance, and it will sound better out front.
8. Never unplug equipment with the levels up.
9. Observe mic-handling etiquette. Don't cover the head of a mic or point it at the monitors.
10. Indoctrinate a friend to help you mix.
11. For a basic system, you'll need a powered mixer or a mixing console and a power amplifier, a minimum of two loudspeakers and one or more monitor wedges, a graphic equalizer (or two-one for the mains, one for the monitors), a compressor, a signal-processing unit such as a reverb or multi-effects box (some mixers have built-in effects), an assortment of dynamic microphones, and a direct box or two, depending on your setup requirements.
12. Make sure all the components of your P.A. are in good working order, and check all your cables before you take off for a gig.
13. Get a graphic equalizer and learn the frequencies as they translate to notes on a piano or guitar. This will help you recognize and de-emphasize problematic feedback frequencies in different rooms.
14. Familiarize yourself with compressors-a little compression for the whole mix on a smaller P.A. can smooth out the sound. But don't overdo it!
15. Use a reverb or other effects unit to fill out vocals or add texture to drums and other instruments.

Karen Stackpole schlepps tons of gear every week as percussionist and location recording engineer. Many thanks to Andy Heller, Andy Lipnick, and John Karr.