Spectral Analysis, your spectrum of frequencies

Sound is all around us and it is related to frequencies.
If we narrow down the term ‘sound’ to the frequency-range that is audible for humans it becomes visible that we can hear only a very small range.

Our day-to-day interpretation of sound relates to the audible frequencies.
The indicative graph below illustrates that the term ‘audible frequency’ is very relative.

Spectral Analysis, your spectrum of frequencies -

The human hearing can identify if a tone is relatively low or high and it can indicate the ‘noisiness’ of what we hear.
An acoustic camera can do the same, but in a objective and detailed manner.
When an acoustic camera is active, all microphones in the array are actively listening to all frequencies.
Streaming data is recorded form 20 Hz to 23.4 kHz

The recorded sound-pressure of each frequency is plotted in a graph.
The result can be a spectrum as shown below.

Spectral Analysis, your spectrum of frequencies -

Insights: Step One

A peak in the spectrum will indicate a frequency with a relative high strength.
By zooming in on the peak, the exact frequency becomes clear. This is step one of the valuable insight.
In this case we selected a small range around a visible peak, the Sorama Portal Software tells us it is 8788 Hz.
This occurrence of 8788 Hz has taken place somewhere during the measurement cycle.
If you want to know when exactly this occurred, the Spectrogram Analysis or Waterfall plot will show you the frequencies over time.


Insights: Step Two

Step two of the insight is localizing the exact source of the sound.
By selecting the frequency, or a wider frequency range, the software can visualize sound on top of the camera-image.
With a color-mapping related to the recorded sound-pressure, the source that emits the frequency gets the most intense color.
This process is called beam-forming, also known as far field imaging.

These are the two steps where the spectrum adds value in making sound insightful.