Sounding

When carrying out leak investigations, it is always useful to be able to see and listen back to any recordings taken. With Sounding, you can take samples off all types of assets directly, or using the sounding base provided, you can place the sensor onto the floor and take samples over a section of ground to really pinpoint the leak.

Default sounding

Default sounding is ideal for pre correlation investigations to confirm sound is present on all assets being used.
To carry out sounding you can either

·         Open a Waypoint you are working on, select ‘Sensors’, tap on the sensor you wish to use and select sounding. (Doing it this way will save the sounding session in the Waypoint making it easier for engineers to see what work has been carried out)

·         On the map page, tap on ‘Devices’, select the sensor you wish to use and select sounding. (When you do it this way, a sounding session icon will appear on the map. You can tap on the icon and look back at the samples as well as listening to them back)

Once on the sounding page, you will be given the option to filter the frequency range, if you know the frequency of the leak you are looking for, drag the limits inward so that you are only listening for the sound you want. You are also able to change the volume in case it is a particularly quiet leak you are looking for.

After filtering the frequency to the limits you want, place the sensor onto the asset you wish to listen to and tap either ‘Short sample’ (a 2 second sample for use when there is very little ambient noise and low levels of usage, mainly for a night shift) or ‘Long Sample’ (a 5 second sample for use when in a busier area so you are more likely to get a point in time where the leak is audible over background noise).

Once you tap the sample you want a pop-up message will appear to tell you that a sample is being recorded. If you can see the sensor, you will also notice that the LED turns red when a recording is in progress. After the recording is complete, a bar chart will appear showing the RMS (Root Mean Square which represents the average strength or energy of a sound signal over a period of time) on the y axis, and the number of samples on the x axis.

As you scroll down, you will see the sample in more detail. You can listen to the noise back (we recommend using headphones) as well as see the FFT and STFT graphs for the recording. If you listen back and the noise seems distorted or you can hear something masking the leak, press the 3 dots and the bin icon. You will then be asked if you want to confirm the deletion, once done, take another sample and confirm that the noise is clean this time.

Repeat this process over multiple assets (either all of the assets within the vicinity of your Waypoint, or just over as many assets as you want if you are looking for something new) as you take more samples, you will notice that more bars appear in your chart. As the volume of the noise increased the bar will get larger, and as the sound starts to die away the bar will begin to reduce in size. If you want to jump to a particular sample without scrolling through, just tap on the bar you want to listen to and it will take you directly to that sample.

If you want to change the filters after recordings have been taken, tap on the filters Icon at the top of the screen, when the filters are changed it will alter the FFTs and STFTs to show only the frequencies you want to see. As well as changing the RMS level.

Distance mode

If you have been able to correlate and you are looking to pinpoint the exact location of the leak, then distance mode is here to help!

When you open the sounding function, you will see ‘Distance mode’ with a toggle next to it, switch this on and it will appear green. You will then be prompted input the distance you want to leave between samples. You can also filter the frequency to make sure you are only seeing the frequency band that you want (we advise that before sounding in distance mode, you use the default sounding on the closest asset, find out what frequency the leak noise is, and use this when filtering for distance mode). Once this is set, place the sensor onto the sounding base, set it on the floor and tap on ‘New recording’ on the app. 

A pop-up message will appear to tell you that the recording is in progress and the LED on the sensor will turn red while recording. Once complete a bar chart will appear showing the RMS (Root Mean Square which represents the average strength or energy of a sound signal over a period of time) on the y axis, and the distance between samples on the x axis.

We recommend taking 5-10 samples along the main, the noise should get louder as you are getting closer to the leak and then quieter as you start to move away again. This should lead to a bar chart like below. If you wish to listen back, you can scroll through the samples, or, tap on the bar you wish to jump to.

Repeat the process in reverse order to make sure you are getting the same result, leaks don’t come and go, the result should be the same each time.