What’s Your Number?

Posted on by Steven Reed

Since volume is such a highly debated issue for most every church, one of the essential items for every tech team is a Decibel Meter. A simple device, or even a free program on many smartphones and tablets, that scientifically and objectively measures the sound level. These devices then output the information into a number that can then be used to establish consistency and even as a common reference point for making changes. 

You might be wondering what is this ‘decibel’ that we are metering? As inches and feet are to distance, a ‘decibel’ is to the level or volume of sound. As a very common term in the world of audio, ‘decibel’, which is almost always referred to as ‘dB’ for short, will often be used to refer to overall volume, ‘whoa we hit 103 dB today’ but also for relative changes in volume, ‘maybe bring that down 5 dB’. This provides a measurable standard to replace sophisticated terms such as, ‘a little bit’, ‘schosh’, and my personal favorite a ‘smidgen’ as in, ‘can you bring it down just a smidgen?’ 

So just like someone from the U.S. trying to use the metric system, or really anytime you encounter a new system of measurement, it’s helpful to have reference points to understand the scale otherwise you will be confused. Below is a simple chart of common sounds and where they typically register on a decibel meter. Keep in mind that the sound of an object will be louder or quieter based on your proximity, or how far away you are, from the object. For instance, being 5 ft away from someone talking normally registers at 60 decibels but if you were a few inches away from their mouth it would register much higher.

Equally important to understanding the intensity of a sound, is to understand how it affects your body. Specifically, how long you can be exposed to different volume levels without pain or suffering permanent damage. OSHA (the U.S. Occupational Safety and Health Administration) along with many other organizations dedicated to the well being and health of your hearing, tell us that all sounds that register below 85 decibels will not create discomfort and have no time limit for exposure. It is once you cross this threshold (85 dB) that the time to discomfort and damage shrinks exponentially. The formula is that for every 3 dB increase in volume over 85 dB the time of exposure without damage is cut in half.

Knowing this information helps you make a purposeful decision about what volume the sound will be each week, instead of just responding to the loudest or most influential complaints. Using a decibel meter while you mix will also help ensure the consistency of your services, so the volume is the same week to week. Being consistent in volume will then show up an interesting phenomenon, which is that most people cannot tell the difference between, ‘I don’t like it’ and ‘it’s too loud’. It’s not a mystery that we, as humans, turn the music we like up and turn the music we don’t like down so when you are confident that the volume level is consistent you can start to ask better questions of those who are displeased. Things like, ‘Was it too loud last week as well?’ or ‘What part of the service was too loud?’ or ‘Was there any part that was at the right level?’ 

Still up for debate is what your weekly decibel number should be but for now the first step is to just get started with a decibel meter and we will have more information in later articles. Here are some tips to help get you started.

Tips: 

  • The case on your phone may alter your results, similar to how cupping your hands over your ears increases your ability to hear. 
  • Calibrate your device to others. Most apps have a way to adjust your results. Do this by putting a consistent tone through your sound system (i.e. pink/white/brown noise or just someone singing a sustained note for a long time) and have everyone stand in the same part of the room to then synch each device to a common number so you are comparing apples to apples. 
  • Standard decibel meters only measure at one note: 1K or 1,000 Hertz or in standard notation that’s a little sharp of B above middle C, which is a good average of most sound. However, it does nothing to measure extremely low or high sounds. If that is a concern you can look for a decibel meter that measures low sounds and high sounds as well. You can also use an RTA (real time analyzer) like this one that is also available in an app. 
  • If you buy a physical meter, most people use ‘C weighting’ and ‘Slow Response’.