Meet Leq – A Better Way To Measure Sound Levels at Church

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Kungpow Product Sound Levels at ChurchIn this installment of IT MIGHT GET LOUD, I would like to introduce you to a concept that will revolutionize your relationship with SOUND LEVEL METERS.  Its called Leq, and in short its a way to average your sound level over an entire set of music, instead of a few seconds.  So how is that revolutionary?

Kungpow Production article on Sound Levels at ChurchMany of us have experienced the tough conversations with pastors, parishioners and staff.  Its too loud, and what are we to do.  Eventually someone discovers that many churches set a Sound Level target of 85~95dB and require the sound mixer to keep the sound level in the room below the maximum acceptable level at all times.  And so began my relationship with the Radio Shack Sound Level meter.  I still find these babies everywhere.

Measure sound levels at church with a Radio Shack SPL meterTHE PROBLEM: Typical sound level meters indicate the sound level averaged over a few seconds.  What we should be interested in is the average sound level across your entire worship set, or perhaps the entire service.  After all, we explore all sorts of dynamics in our worship set, from broken down moments to emotionally charged outpourings when it actually is appropriate for the drummer to ride the CRASH.  The quiet parts measure really low, in the 70s or 80s of decibels.  The loud moments can cross 100dB, but only last a couple minutes of our entire service.  If only we were able to measure the sound level averaged over the entire set we would be in a much better position to assess the level of exposure our congregation and musician/sound operators experience to sound.

OSHA SAFTEY STANDARDS  OSHA sets safely standards for workplaces. Here’s where t  he numbers and the debates about safe listening levels begin and end.  Here is how you read this mumbo jumbo: Most worship sets last 30 min to an hour, and according to OSHA you can safely run at 105dB for an hour. Still 105dB is really loud to a lot of folks. That drives many churches set sound level targets in the 85~95dB range. Here’s the problem.  OSHA and other state and civil organizations use a particular type of reading to determine average sound level over time, and you should use it too.

OSHA Standards for sound levels at church

Setting Sound Levels at Church with Leq MeteringENTER LEQ the EQUIVALENT CONTINUOUS NOISE LEVEL. Leq is the preferred method to describe sound levels that vary over time, resulting in a single decibel value which takes into account the total sound energy over the period of time of interest.

Sound levels fluctuate over time. The Leq meters captures and stores level samples over a period of time, say 30 minutes, then calculates an average energy Leq value. The math to do the averaging is not a simple calculation given that decibels are not a logarithmic scale. As a log scale, a reduction in volume of 50% would measure a mere 3dB of change, and double the amount of safe exposure according to OSHA in the UK. However OSHA USA Standards use a “5dB per doubling of exposure” exchange rate. And that’s how we get the chart above.

Leq is the method used by the city to measures and enforce neighborhood noise laws at outdoor concerts. Its also how OSHA measures workplace exposure. And I very much recommend you use it to measure your continuous sound level at church.

SETTING A SOUND LEVEL TARGET

There are a couple things to keep in mind when setting your Leq target:
1. Consider the number of hours you and/or your volunteers are going to spend at church on a Sunday. Set your safety target for those who will be exSetting Sound Levels Targets at Churchposed the longest.
2. Set an Leq target, run a service within it, then gather feedback from pastors, staff and congregants. Try a few targets to hone in on what’s right for your community.
3. Set your Leq measurement device to average for the entire worship set, or perhaps the entire service.
4. Use A weighting and the Slow setting. Its the right thing to do!

THE PLAN:
Here’s a 3 step plan you can implement this week to change your relationship with your sound meter:
1. Buy a Leq Meter
2. In your next staff meeting take a moment to tell your team what you’ve learned about Leq metering, how OSHA and Civil Noise Enforcement use it to measure sound level and you should too!
3. As a starting place, set your Leq sound level target for 6~10dB below your previous non-Leq target.

LEQ SOLUTIONS: 3 WAYS TO GET IT DONE
Pick the approach that will work best for your community. They all offer the Leq method of sound measurement:Leq Meters for Setting Sound Levels at Church

1. iOS: STUDIO SIX DIGITAL  iTestMic + Audio Tools App + SPL Pro + SPL Graph in-app purchases $250 + iPod

2. Handheld: EXTECH 407780A Integrated Sound Level Meter  $1200. The Extech offers a calibrated solution that looks a lot like a sound level meter but adds the Leq function we’re looking for. This is the lowest cost way I can find to make a calibrated Leq measurement

3. PC: 10Easy RT  $1742 + PC. Yes its expensive but it is the best way to monitor your Leq and log your services so you can provide critical insight to your team on their performance over the course of weeks!

We would love to know what you think!  Join the conversation and leave a comment below !

Want to see how others are dealing with it? Check out these public documents for inspiration!

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