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by Kathy Patrician     Added January 16, 2009

Overhead suspension (also known as “rigging” in professional circles) of loudspeakers is a task that many church audio installations have in common. Since rigging speakers can be both difficult and dangerous, it is surprising that “do-it-yourselfers” sometimes create and install their own rigging, unaware that they may be using unsafe methods and materials. Just because it may be physically possible to suspend speaker enclosures overhead without professional guidance or proper materials, that does not necessarily mean they are safe. Absence of a disastrous rigging failure may simply mean that the church has been lucky so far. People sitting under unsafely suspended speakers may be in danger of injury or death.

Generally, people don’t try to save money by building their own amplifiers. But sometimes there seems to be a perception that money can be saved by making rigging a “do-it-yourself” job. This idea may overlook some basic safety issues.

To begin with, the person responsible for administering the rigging project should perform their due diligence in planning and documenting the steps that will be taken fromthe beginning to the end of the job. This will facilitate an orderly procedure and minimize the impact of surprises along the way. The church building’s roof structure should be evaluated by a professional engineer for its ability to support a load. Look for help from the best rigging contractor available. A structural engineer, licensed in the jurisdiction of the job, should confirm that a particular structural member is capable of supporting the load. In other words, make sure that it will be safe to hang speakers there in the first place. The load bearing capacity at each attachment location in the roof structure should be documented as safe by the engineer. In addition, any assembly of Unistrut or other parts used for loudspeaker suspension should have a drawing stamped by a professional engineer, confirming that it will be safe to suspend that assembly.

It is important to choose speakers that are designed for overhead suspension. They are built to take the stress of hanging in the air and have certain spots on the enclosures, or “rigging points”, where suspension hardware can be safely installed. They also have internal metal bracing, so that the bottom of the speaker will stay attached to the top of the speaker. The speakers should also come with technical data essential to safe rigging. This data includes the location of the center of gravity, rigging points, and full geometry. Choose a manufacturer who provides this technical data when the speakers are purchased. Sometimes it may be possible to buy speakers without this data being automatically provided, and then time is spent by the customer on trying to track it down. Speakers that are intended for overhead suspension, and that automatically come with all of the above technical data, will be easiest to use.

Whoever performs the work of installing speakers suspended overhead should carry all applicable insurance. Find out what the insurance requirements are in the state where the work is done. Professional installation contractors will have this insurance.

Hardware that is rated for overhead suspension is not usually available at the local hardware store. A professional rigging company will use appropriately rated hardware. If speakers are hung using hardware that is not rated for overhead suspension, the danger of catastrophic rigging failure may exist.

In a few rare cases speaker handles are rated for overhead suspension, but normally they are not. If the manufacturer does not state that the handles are rated for overhead suspension, then using them for that purpose may result in catastrophic rigging failure.

Improvisation may be good for theater, but it is risky for rigging. A well-designed rigging system that is the result of the appropriate application of resources (engineering, properly rated parts, skilled installation labor) should install very quickly. In an under-resourced rigging installation, installing technicians, under pressure to work quickly, may cut corners or improvise. This can lead to unsafe rigging.

A safely rigged church speaker installation should include a written plan, professional engineering, speakers that are designed to be rigged and have all necessary data provided by the manufacturer, complete and appropriate insurance, rated hardware, and no improvisation.

Kathy Patrician has worked in the audio rigging industry for 14 years, and in the audio equipment business for several years before that. She is a co-owner of an audio rigging hardware design and manufacturing company, Polar Focus. For more information, visit the company website at www.polarfocus.com.