You Do Not need to Be a Scientist to Find Air Leaks and Partial Discharges

Acoustics researchers use acoustic cameras for sound source detection and analysis, but what if you are not an acoustician and want to find compressed air leaks and partial discharges (PD)? In this article, we explain what can go wrong if you are not specialized in acoustics and how we have solved this problem for you.

What You Need to Consider When Buying an Acoustic Camera

Any acoustic camera can typically locate air leaks and PDs if the sound pressure levels they emit are strong enough. However, if you are not a trained acoustics researcher, using these kinds of devices without any analysis capabilities will not give you the results you need to make informed maintenance decisions, as the gadgets cannot even tell you if the sound source you have located is caused by an air leak or PD. When acquiring an acoustic camera for air leaks, see if the device has air leak recognition and real-time on-device leak and cost estimation analysis. For PDs, the camera should include PD recognition and PD pattern to determine whether the PD is harmless or of a more severe type. In other words, an effective acoustic camera has PD type classification and PD severity analysis possibilities.

Acoustic ultrasonic camera locates a partial discharge that is analysed by the NL Cloud on smartphone

Image 1. Ensure the acoustic camera you are about to purchase offers extensive analytics to get the best value for your money.

An Acoustic Camera Without Analytics Is Like a Car Without a Working Dashboard

Using a standard acoustic camera without analytics is like driving a car without a working dashboard: you can drive, but you have to estimate your speed based on the objects you pass by and you do not know if the tachometer readings have anything to do with reality. With such an acoustic camera, successful air leak and PD audits require expertise in operating the complicated device: adjusting the frequency range and dynamic range manually. The wrong frequency range can affect the detection sensitivity and result in missed leaks and PDs. Furthermore, the incorrect dynamic range can lead you to perceive a leak’s or PD’s location wrong.

After you have located the problem source with an average acoustic camera, it is difficult to determine whether the detected sound source is a leak or a PD or if it is just an interfering noise source. To decipher this, you need to export the snapshots to a computer and analyze them manually. This is a laborious task, and misinterpreting interfering, harmless sound sources as potential problems happens easily. To convert sound recordings to valuable information, you again need to be a scientist. Converting air leaks into air leak size estimates and cost estimates involves using tables or complicated algorithms. However, with PDs, this process is even more demanding, as there are no standardized methods for classifying the type or severity of a PD. In the worst case, you are left with an acoustic camera that offers you no analytics and gives your findings little to no explanation.

What the NL Camera Does Differently

The NL Camera is the market-leading, comprehensive, and fully automated solution for finding compressed air leaks and PDs. The camera has automatic, optimized filters for filtering out interfering noises and automatic dynamic range for both single and multiple sound source modes. In other words, the camera automatically recognizes whether the sound resembles an air leak or PD. As a result, the device is easy to use and does not require extensive training. Furthermore, the camera has real-time on-device analytics: leak size and leak cost analysis for leaks and PD pattern analysis for PDs.

Female maintenance worker detecting partial discharges with ultrasonic acoustic NL Camera. Male worker supervises.

Image 2. The NL Camera is easy to use and requires no expertise.

The camera uploads snapshots instantaneously and automatically over Wi-Fi to the cloud interface where they are backed up and analyzed by the NL Cloud software. You can also use the NL Camera Viewer and NL Camera Viewer Pro software for offline analysis.

The NL Cloud provides you with more in-depth information, such as PD classification and severity analysis. Thanks to the AI-powered cloud, generating automatic reports for air leak and PD audits is effortless and fast.

If you are interested in how the NL Camera can help you, do not hesitate to contact our sales department for further information.


New resellers!

Despite the Covid-19 pandemic roaming around the planet we have been able to keep our staff safe and wheels rolling. The NL Cameras have been shipping out from our production facility to our new and existing customers around the globe.

The interest towards our technology is constantly increasing and we have extended our local reseller and distribution network. We are glad to announce our new partners:

Icodata (Germany)
Eskeland Electronics (Norway)
Belmet (Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, Kosovo, Northern Macedonia) 
Ocean Winds (Spain)
Victory Instrument (Thailand)
Mekong Technologies (Vietnam)

Together with our channel partners we can provide top quality support for the NL Camera customers around the globe.

The enthusiasm of our new channel partners around the world has been a pleasure to observe. We are currently in the process of actively expanding, especially in Europe and the APAC region. As soon as the situation allows for it, we will be in an excellent position to accelerate the on-site promotion and customer activities. We will do our best to support our partners also during the crisis, and hope everyone stays safe!“, Kai Saksela, CEO, NL Acoustics.

All our international partners listed here

If your country is not listed and you are interested in becoming a reseller contact: anna.nykanen(at)


Acoustic Cameras: Why Does the Number of Microphones Matter?

When comparing the datasheets of different acoustic camera manufacturers, you quickly notice that the number of microphones varies a lot. In this article, we will explain the technology and science behind acoustic cameras and why having enough microphones really matters.

More Microphones—Better Acoustic Sensitivity

Bigger is not always better, but in acoustic imaging, having enough microphones plays a critical role. In general, increasing the number of microphones improves acoustical performance. Acoustic cameras generally use MEMS (microelectro–mechanical systems) type microphones, as they provide great performance, stability, low power consumption, and are small in size. MEMS microphones can typically pick up loud noises (usually over 120 dB(A)), but they also have a high self-noise level, which means that a single microphone cannot pick up the quietest sound levels. However, this self-noise can be attenuated by combining the signal from multiple microphones. Doubling the number of microphones removes roughly 3 dB of noise. Therefore, the sensitivity for detecting quiet sounds can be increased by maximizing the number of microphones.

By utilizing 124 state-of-the-art microphones, the NL Camera is able to locate air leaks as small as 0.016 l/min in optimal conditions. It is not possible to receive this level of accuracy with a lower number of microphones and without the NL Camera’s microphones that are market leaders in sensitivity.

A graph on how the number of microphones affects their self-noise level and the signals they can detect

Image 1: This example has two signals from two leaks that can be missed if the acoustic camera’s sensitivity is not good enough. The 16.5 kHz leak signal can be detected with a system of 32 microphones and the 18.5 kHz leak signal with a system of 124 microphones.

Better Detection Range and Resolution

The number of microphones plays a critical role in detection range, another important, technical data sheet fact you should pay attention to. As sound travels through air, it is attenuated by 6 dB every time the distance is doubled. An increase in the number of microphones also increases the maximum detection range: the range is roughly doubled by quadrupling the number of microphones.

You might wonder why every manufacturer does not simply increase the number of microphones. It is easy to think that growing costs would be the only drawback. However, this is not true. Multiplying the number of microphones increases the number of audio data signals that need to be processed. This requires a lot of built-in processing power, which explains why portable acoustic cameras with an abundance of microphones have not been widely available earlier.

A quick way to decrease the required processing power would be to reduce the resolution of acoustic images. An acoustic camera essentially calculates the sound level arriving from numerous directions, acoustic image pixels, so decreasing the number of these pixels reduces the required processing power. However, acoustic image resolution is like that of your computer’s display—low resolution makes the image blurry. In a similar way, reducing the number of sound pixels hinders the performance of the device.

A maintenance worker looking for air leaks with ultrasonic acoustic camera, acoustic image pixels visible

In contrast, increasing the number of sound pixels makes fault location more reliable and possible from longer distances. As the distance grows, so does the gap between the acoustic image pixels. If the number of available pixels is limited, it is difficult to determine the exact location of the sound source.

These factors as well as the portable, compact size of the device have been closely considered in the development process of the NL Camera. The NL Camera packs 124 microphones and a lot of processing power. This combination enables industry-leading detection sensitivity, excellent acoustic image resolution and a great range.

Want to know more about the benefits of the NL Camera? Contact our sales department today!


2019 recap: What a ride!

Entering a new decade makes a great chance to reflect on the years that have passed. Entering 2020, it feels as if it was ages since we started the company in 2015, since so much has already happened since then.

When we started the company, we had nothing but a few product prototypes that we had managed to scramble together using limited resources – together with the hunger to make a difference. We recognized a huge potential in the way sound could be utilized to bring value to people, in ways that were being completely neglected at the time. We noticed that we could do significant and meaningful things, such as reduce the energy consumption in the world, using nothing but sound. We could make an impact, while saving our customers’ money and time.

Since the beginning, we’ve continuously been focusing on the most important thing of all – the needs of our customers. Year after year, we’ve developed our solutions further, to help our customers solve their most pressing problems as well as possible. Of course, we’ve stumbled upon a lot of challenges as well; getting our solutions and advanced technologies to work in a scalable way has been no easy task.

But each year we’ve kept our focus steady, and by solving these challenges we’ve managed to build something that keeps on growing. And we know this growth will continue. Looking at our yearly turnover, our average growth rate has been 350%. The year 2019 was our most successful year so far by a huge margin. And 2020 will definitely continue this trend.

Today we are proud to have our solutions used by customers and partners in places all over the world. Next year, we will introduce a couple of new partnerships that we believe will help us spread the awareness of the great things our company can do even further.

We are proud to be changing the world using sound. 

PS. We are also hiring.

Kai Saksela
Co-founder / CEO
Noiseless Acoustics


NL representing Finland at Slush!

We make sound visible! Here Kai demonstrates how our acoustic camera hears a tiny air leak amidst the chaotic soundscape of an expo hall and shows the location visually. 


Locating leaks at ice rink construction site.

Say goodbye to soap water or leak detection fluids. Finding possible leaks with our acoustic camera saves time, effort and money. Here Findri OY finds results at Pyrkkä ice rink construction site