It takes a lot of research to assure an “apples to apples” comparison, and many specs simply don’t include enough background information to allow this. Feeding a loudspeaker with less than its rated power presents no danger.

In fact, it will have a longer, happier life with less power. I recommend limiting the input power to no more than one-half (-3 dB) of the continuous rating for reliable operation.

In the preceding example, this would mean using an 800-watt amplifier, feeding it typical program material (10 dB to 14 dB crest factor) and driving it just to the brink of clipping as a maximum.

Under these conditions, the amplifier will be producing about 80 watts or less into the loudspeaker, which is safely below the continuous rating.

Since the amplifier has a potentially large output, care must be taken to assure that low crest factor program material is not turned up too loud as it could damage the loudspeaker.

Finally, it’s important to realize when the point of diminishing returns is being reached when turning up the volume on a sound system.

Each 40 percent increase in applied voltage to the loudspeaker produces twice the input power, and a slight (+3 dB) increase in sound level.

Remember that with audio it is the proportional chance that matters. As the volume of the system is increased in 3 dB steps, eventually the limits of heat dissipation are reached and the next 3 dB “breaks the camel’s back.”

A loudspeaker is very near its maximum loudness at one-half of its rated power. There is nothing to be gained by going further and the loudspeaker will likely suffer permanent damage.

Advancements in automotive technology have produced vehicles with greater efficiency and lower operating cost due to reduced waste.

The audio industry should have a similar goal – achieving the desired SPL using less amplifier power.

As efficiencies increase, the need to dissipate lots of power should diminish – as should our fascination with high power ratings.

Pat & Brenda Brown lead Syn-Aud-Con, conducting audio seminars and workshops around the world. Synergetic Audio Concepts (Syn-Aud-Con) has been a leader in audio education since 1973. With nearly 15,000 “graduates” worldwide, Syn-Aud-Con is dedicated to teaching the basics of audio and acoustics. For more information, go to http://www.synaudcon.com

More articles by Pat Brown on PSW:
Specification Sheets: What Do The Charts & Graphs Really Mean?
The Vital Impact That Acoustics Can Have On Sound At Your Church
How To Illuminate The Audience With Beautiful, Consistent Audio Coverage
Proper Loudspeaker Placement: How To Avoid Lobes and Nulls
Ten Reasons Why Church Sound Systems Cost More
What Makes A Quality Loudspeaker?

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