Dorset Sound & Communications

Sound system design for the 21st Century

SoundTips
The Central Cluster

Eight times out of ten sound system consultants and reputible contractors will recommend that speakers be arranged in a point source or central cluster. A central cluster can consist of one good full range cabinet speaker for smaller rooms. In larger rooms, wide rooms or irregular spaces it may be made up of either several full range cabinets or an array of separate bass cabinets, mid range speakers and high frequency short throw and long throw horns.

In either case the point source concept has many advantages over systems consisting of widely split cabinet speakers. With modern computerized analysis systems we have been able to finally see how split speakers cause cancellation "dead spots" in auditoriums. Seats exactly the same distance from split speakers (down the middle of the aisle) will hear full sound. All other seats will experience some kind of sound loss. Some will lose bass. Some will lose high frequencies. The most noticeable will lose mid-range frequencies where all of the consonants of speech (B, T, C, etc.) occur. The consonants allow us to distinguish and understand words. Most people will call these areas "dead spots". Split speakers are usually installed by well meaning volunteers, building contractors and electricians. For ease of installation they tend to be mounted low, creating direct echoes off of the rear walls and side walls. Echoes also degrade the ability to understand words. Sound is often too loud for the front rows while the back rows don't get enough. A well designed point source system will direct sound down into the audience keeping it off of the walls and covering more evenly side-to-side and front-to-back. There will be no "cancellation dead spots". The cluster also will improve the feedback threshold, meaning that the system can be made louder than possible with a split system.

A note about safety. Hire an experienced, insured, licensed sound contractor to hang speaker clusters. Clusters are mounted high over the front of center stage (often over the lectern or pulpit). Clusters hang over people. It must be done right. You want the building to fall down first and not the speakers. The liability of a jack-leg, trunk-slammer or do-it-yourself installation using inadequate support structure and home center hardware is enormous. Note that it is very difficult to find chain, links, eyes or hooks in home centers that are legally rated for overhead suspension -  made in China from the lowest quality steel. We employ professionally load rated hardware and engineered rigging systems.  They are expensive, but what's a life worth?

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

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