Sound Level Meters
Many churches use a sound level meter to judge how loud their services are, and many more should be doing this. One of the most popular meters for this use is the Radio Shack model 30-2055.
It has a number of things going for it. It is inexpensive (always a concern for most churches), is easily available in many parts of the world, and is reasonably accurate. I have tested many of these and found that most have a level calibration that is close to correct, even though the frequency response leaves something to be desired. As Radio Shack notes on their website:
"Disclaimer: This meter should be used for home/hobbyist use only. This meter does not meet the requirements set forth by the American National Standards Institute (ANSI), Standard S1.4."
The ANSI Standard S1.4 describes how a sound level meter should work and specifies grades of meters. The old 1971 edition of this Standard specified accuracy limits for "type 3" meters (some samples of the RS meter met type 3). The current version specifies "type 2" meters for General Purpose use which are more accurate than the old "type 3" meters, "type 1" Precision meters, and "type 0" Laboratory Standard meters.
As I mentioned last newsletter, most sound level regulations are done with the meter set for A weighting and Slow response speed. Therefore I recommend churches use these settings to measure the levels of their services since that allows them to compare their measurements with those of other churches and with regulatory sound limits. The RS meter will probably give a reading that is within about 3 or 4 dB of correct when set this way.
What if you want to get a better meter than the Radio Shack? What should you look for? First thing to look for is a meter that meets ANSI S1.4 "type 2" or "type 1" specifications. Type 2 meters will be much more affordable than type 1. In Europe look for a meter that follows the IEC Standard. The meter you buy should have a setting to measure with an A weighting filter and with a Slow averaging time. If possible try to buy a meter that can measure Leq (Level equivalent) which is the level averaged over a period of time such as your entire service. A meter that can measure Leq will allow you to easily determine if you are in compliance with noise ordinances such as the NIOSH recommendations.
It is possible to spend many thousands of dollars for a top of the line sound level meter such as those made by Bruel & Kjaer in Denmark, but such an expensive instrument is not needed for typical church use. Look at the links provided in this newsletter for sound level meters at a wide range of prices, including quite affordable models.
Ray A. Rayburn
Ray@K2Audio.com
http://www.K2Audio.com
