Thursday, June 29, 2006

Detailed Explanation of How Sound Waves Behave at Places of Worship

There may be terms in this article you are unfamiliar with, or perhaps you may be unclear regarding our use of the term[s] in a specific way. We are pleased to offer an audio glossary so that you may be become better acquainted with the language in this article.)

Certainly not just true of places of worship, excellent sound quality (not just quantity or volume) is the primary goal for purchasers and professional vendors (installers) alike. Because sound quality is important for church sound systems, it is helpful to become familiar with some of the more general aspects of audio or sound. In this article, we will examine in laymen's terms how audio/sound is produced, transmitted, and received by the target or listener (congregation, audience, etc.) and we will describe exactly how the audio/sound wave behaves.


I. How Audio is Produced, Transmitted & Received (Heard)

Sound waves, what we call audio, are produced by vibrations in the wave source, such as vocal chords, percussion instruments, guitar strings, etc. Any easy way to imagine sound waves is seismic waves. Similar to the illustrations we've all seen on news broadcasts, seismic waves travel much like sound waves - from the source of the vibration - to the target where they are felt or heard, as an earthquake or a noise or both as the case may be. In a place of worship, the most common sound sources are musical instruments, loudspeakers, and of course human vocal cords.

When an audio source (in this case let's say a female soloist's vocal chords which produce movement when she forces air through them) produces sound, the mechanical vibrations of the vocal chords move the air which is immediately adjacent to them. This movement continues from her throat to her mouth and out of her mouth ultimately to the microphone, alternately pushing and pulling the surrounding air from its resting state. Each back and forth vibration produces a corresponding pressure increase (compression) and pressure decrease (rarefaction) in the air (hence the sound wave - ebb and flow).

A complete pressure change (wave), or cycle occurs when the air pressure goes from rest to maximum to minimum and back to rest again (from valley to crest to valley in the case of an ocean wave). These cyclical pressure changes travel or radiate outward 360 degrees from the singer's vocal chords, forming a pattern called a sound wave. These sounds waves, transmitted in premium quality by a professionally installed sound system, eventually enter the air space around the ears of a congregation member and interact with the inner ear (tympanic membrane and ear drum) which begin vibrating in unison with the waves, thus allowing the member to "hear" the singer.


II. Acoustic Behavior of a Sound Wave (Audio)

A simple sound wave can be described by its frequency and by its amplitude. The frequency of a sound wave is the rate of which the pressure changes occur (how fast the waves roll in and out in the case of the ocean wave). It is measured in Hertz (1Hz is equal to 1 cycle each second or 60 cycles per minute). The audible range (what we can hear) of frequencies to the human ear extends from a low of about 20Hz to a high of about 20,000 Hz. Animals such as bats, dogs and cats have a much great audible range that humans do explaining why our pets are so much more sensitive to loud radios and television settings than we are. The same phenomenon is true of light - the sun's light travels in a spectrum far greater than human eyes can see unaided (such as ultraviolet, infrared, x-ray, etc.)

If at any point in the transmission process an interruption occurs, the sound quality is diminished - sometimes heard as static, clicks, dead spots or other anomalies in the audio transmission. ProAudioSuppliers.com is experienced in the customization and installation of premier sound packages for places of worship. Our installers work directly for the company and not subcontracted, so we can say with confidence that your new sound system will operate free of interference and quality-disruption for the life of your system, guaranteed.