How Do We Measure Noise

July 11th, 2018

Noise is measured by the pressure produced by sound waves, via a recording device, or an instrument like your ears.

Is there a sound if no-one hears it? 

Yes and no. If nothing is there to hear it, then there’s no sound being produced, just a pressure wave. Ok, so perhaps we’re becoming a little too esoteric here, but in our line of work it is interesting to consider how is created, received and processed, so that we can ensure the best noise reduction through our products.

Another thing to consider is the power of the sound wave and how we quantify it. Our ears can hear the tiny whine of a mosquito passing by our ears, at the same time as we can register a jet plane 30,000 feet overhead.

The pressure wave created by the engines of an aeroplane is around 1 billion times more powerful than the sound made by a passing mosquito.

Decibel Scale (dB)

Using the decibel system, the smallest audible sound is measured at 0 dB. Following this, a sound that registers at 10 dB is ten times more powerful. Consider this to be the sound of your breathing. Then a sound of 20 dB is 100 times more powerful than one of 0 dB.

The decibel scale is a logarithmic system. For every incremental factor of 10 dB, the power of the sound wave increases exponentially, by a multiple of ten. So it follows that at 30 dB, you are experiencing a noise that is 1,000 times more powerful than the smallest audible sound.

decibel-readings-infographic-hugo-carter-silent-windows-UK

Here are some examples of common noises and their place on the decibel scale.

  • 0 dB threshold of hearing
  • 10 dB barely audible breathing
  • 30 dB a whisper in a quiet space at 6”
  • 60 dB a normal conversation
  • 80 dB average city traffic
  • 88 dB trains at 25 ft
  • 105 dB a jet plane 100 ft overhead

What’s important to understand is that the gap between each of these examples is far greater. The difference between a whisper and a normal conversation is far smaller than the difference between a normal conversation and city traffic.

This becomes interesting to us when we consider how to implement noise reduction through our windows’ designs. Using a system that effectively dampens the pressure wave of the noise, we can create at least 30dB differential.

If average city traffic noise when you’re on the street is around 80dB, when stood behind one of our windows this is reduced down to around 55dB – quieter than an average conversation.

Hear the difference made by Silent Windows from Hugo Carter.

Question: If a tree falls in the forest and no-one is around to hear it, does it still make a sound?

Answer: Not if you’re stood behind a noise reduction window from Hugo Carter.

Contact Hugo Carter to book your no-obligation Noise Survey.

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