Dorset Sound & Communications
Sound system design for the 21st Century
Professional PA speaker systems are much different than home (consumer grade, home theater, stereo) speaker systems. Professional speakers are much, much, much...more efficient than stereo speakers. We need to get the biggest bang for our amplifier buck and a touring or suspended system needs to be as compact as possible. Would you rather have thirty or forty home stereo speakers or one moderate sized professional speaker hanging in the front of your auditorium? It is that kind of difference. Professional speakers tend to have flatter frequency response. Bass does not dominate the midrange or the high frequencies. Professional speakers tend to be intelligible in the midrange frequencies. Home stereo speakers tend to be bass and treble heavy ignoring the midrange. It is the bass and the cymbals that wow most people in stereo stores. (I am not talking about classical audiophiles here, so lighten up and don't call me). Professional speaker systems tend to have larger cabinets than home speakers. You need that cabinet air volume for efficiency. Professional speakers are designed to project to groups of hundreds or thousands of people. Stereo speakers only need to be heard in a living room with ten listeners maximum.
Speakers are a vital part of the audio chain. Whenever possible, we install a "point source" or "cluster" speaker system. This means that all of the speaker components for the auditorium are located in a central location, usually directly over the front of the stage area, at the ceiling, pointed down at the congregation. The sound is localized to the platform or stage where the most the activity takes place. It is important that the audience receive their visual and audible cues from the same direction. As the audience is looking at the pastor speaking from the pulpit, he should be heard from the same approximate
position, not from the side or rear of the sanctuary. Echo prone rooms may call for specialized clusters or line array speakers.
Sometimes a room has an odd shape, a low ceiling, a balcony or is long and narrow. In such cases we may install a delayed satellite cluster or delayed ceiling speakers. Delay zones will have their own amplifier(s), equalizer(s), and signal delay(s). The signal delay makes it work. The electrical audio signal traveling to a speaker is instantaneous (299,792x103 meters/second). When it is converted to sound in air, it travels much, much, much...slower (331 meters/second). Sound from a single amplifier would arrive at two speakers fifty feet apart at essentially the same time. You, sitting in your favorite last row seat, would hear the satellite speaker closest to you first, then the main speaker farthest away fifty milliseconds later as a disturbing echo. A digital electronic signal delay holds up the audio signal to the near speaker amplifier until sound from the farther speaker arrives. You don’’t hear an echo, just the synchronized, intelligible sound. Ideally, you will not even perceive the delayed speaker, only that you are able to hear clearly. Delays are an important tool. They are set at the time of installation. DO NOT TOUCH THEM. Tampering can lead to disaster. Leave adjustments for your sound contractor. Fortunately, modern digital signal processors hide most of these functions behind a blank equipment face nearly eliminating service calls to repair tampering attempts.
DS&C specifies and installs a number of reputable professional speaker system brands and models tailored to each situation. Give DS&C a call for help assembling your sound system and the training to use it effectively. We can also set up preventive measures and scheduled maintenance visits. Don't be caught unprepared. Enjoy effortless sound. Do it now!