Nothing is worse than starting your event off with a bunch of ear-piercing shrieks coming from your speakers. Or no audio at all. Although sound glitches are common, they don’t have to be. Audio feedback and numerous other annoying problems can easily be avoided or quickly fixed.
Whether you’re working with a professional AV team or not, it behooves you as an event planner to know basic preventive measures. Here are some tips, straight from the pros, to help you treat your audience to crisp, clear sound instead of a cacophony of weird, unpleasant noises.
That screeching and howling you hear is recirculating amplified sound. If there is amplified sound coming from a speaker and you aim an open mic toward the speaker, the mic picks up that sound and re-sends it to the amplifier, which sends the re-amplified sound back through the speaker, creating a continuous loop.
Proper gain structure will prevent the problem (gain is the loudness of input sound, whereas volume is the loudness of output sound). Or you can use a digital feedback reducer, but there are some simple preventive techniques:
- Choose the right mic (for example, a headset may be a better choice than a lapel mic)
- Don’t let speakers or performers cup the mic with their hand(s) because this alters the mic’s directionality
- Point microphones away from speakers
- Turn down all system components
- Maintain as much distance as possible between microphones and speakers
- Put speakers closer to your audience
- Use in-ear monitoring devices in place of floor monitors
Over-modulated sounds create fuzzy/buzzy overtones we call distortion. Either the content itself is poor quality and needs to be replaced, something is bad in the signal path, or the gain structure is off and should be properly adjusted.
This is the opposite of distortion, caused by under-modulated sound or system noise leakage. Properly adjusting the gain structure and turning off unused channels should solve the problem — unless your content is bad.
This happens when the sound system is plugged into two different power sources with separate ground points. Disconnecting the shield wire on the receiving end (or inserting an isolation transformer) will clear the problem, but keep all equipment safely grounded. Never disconnect the power ground!
Echo. Echo. Echo.
Hard surfaces — windows, walls, structures, etc. — bounce sound back at speakers. Try repositioning or relocating speakers, or use curtains, soft covers, or other acoustic-dampening materials.
Crackles and Pops
The usual cause is a bad cable or connector, though they can be caused by a failing computer sound card or speaker driver. Check each cable and connection until you find the culprit.
No, we don’t mean the camera... It’s one thing to understand that you shouldn’t point your mic at a speaker or your speaker toward a big hard surface. But larger events with sound systems that go beyond the basics call for professional intervention. Chances are good you won’t know how to properly set gain structure or have the equipment to do that. Besides, not all problems are easily resolved. In some cases, it takes audio engineering expertise to identify and correct the issue. And sometimes it takes extended troubleshooting to uncover the cause.
Working with a professional AV company is the simplest, most effective way to prevent audio feedback and other problems. An experienced audio technician can quickly pinpoint and fix problems that would confound a non-professional. Pros also keep their gear in tip-top condition, and they carry backups.
Preparation is the Key to Flawless Sound
It’s easy to see why testing every bit of equipment (and content) before your event goes live is so critical. If something is wrong, it can be fixed. Poor quality sound will ruin any type of event in a heartbeat, making attendees sorry they wasted their time and, certainly, discouraging them from coming back. You want to give everyone a memorable experience, but not that kind of memorable experience!