Sound systems used for business meetings, small clubs, weddings and the like, will often provide sufficient coverage when only Left and Right loudspeakers are deployed.
For larger applications, line array systems can cover longer distances, providing respectable uniformity of sonic levels throughout a medium-sized room, and sometimes even in large rooms.
But what do you do when the level is too low in the rear or sides of a room, or the intelligibility underneath or above a balcony suffers? If the overall system level is merely increased, then the front and middle audience areas may become too loud or acoustical reflections from the rear wall bouncing back to the stage can make it difficult for the performers to hear their stage monitors properly.
Typically referred to as Delay Speakers because they’re almost always driven through a digital delay device, these small and mid-sized ancillary loudspeakers can lead to a huge improvement in leveling-out the acoustical coverage of a sound system, thereby contributing strongly to audience satisfaction.
Figure 1 — This illustration shows two lines of delay speakers used to augment the main loudspeaker cluster(s). The use of delay speakers applies equally to augmenting a single main central loudspeaker cluster, L-R loudspeaker clusters, or L-C-R loudspeaker clusters.
TIP: A basic rule-of-thumb: if the room is 100 feet deep or more, delay speakers should be deployed at around 40 to 70 feet from the main sound source(s). In deeper rooms, such as arenas and conventions centers, two or three lines of delay speakers are often used.
In Broadway theatres, hotel ballrooms, performing arts centres, nightclubs (usually those that have balconies or deep dimensions) and even large open-air concerts, the humble delay speaker often makes the difference between a sonic mess and a successful event.
But for optimal usage, it’s not as simple as just placing the delay speakers in a convenient location and setting an approximate delay time. Doing so will get you started, but below are some ideas that can make the end results really shine.