Frequently asked questions about noise measurement.

An acoustics specialist analyses and evaluates existing noise sources. The aim is to develop effective solutions that minimise the impact of noise sources on their surroundings. Our focus, however, is not only on measuring noise but also on finding and precisely identifying its cause. We are particularly experienced in detecting specific types of sound such as low-frequency tones, hums and subsonic frequencies, which are often stressful for the human ear even though they are not always loud. Our noise measurements are based on recognised standards such as DIN 45680, which was developed specifically for low-frequency noise and its assessment.

Professional noise measurements are essential to quantify the actual noise exposure and to assess it correctly from a technical point of view. Especially where sources such as low-frequency sound, hums or subsonic noise play a role, an inadequate analysis can lead to misinterpretation. With modern sound measuring equipment, we record not only loudness (in dB) but also analyse the frequency distribution (in Hz) and the character of the sound. This is crucial, as low-frequency noise exposure is often underestimated even though it can be physically and psychologically stressful.

Noise measurements are required by law in various cases, for example:

• When noise limits according to TA Lärm or DIN 45680 have to be checked.
• In the case of complaints about low-frequency sound sources, hums or subsonic noise in residential areas.
• In building or permit procedures where compliance with noise protection regulations has to be demonstrated. A timely noise measurement helps to avoid conflicts and to clarify the causes of noise exposure on a sound technical basis.

A noise measurement begins with a detailed consultation to identify the relevant sound sources and frequency ranges. We determine whether the measurement should focus on low-frequency noise, hums or general noise exposure. This is followed by the on-site measurement with precise instruments that record loudness (in dB), frequency spectrum (in Hz) and any peak values. We pay particular attention to low-frequency sources and subsonic frequencies, which are often difficult to locate. After the measurement, we analyse the data and prepare a comprehensive report with concrete recommendations for noise reduction.

We use a wide range of highly specialised equipment to ensure precise results. Our sound level meters measure loudness in decibels and at the same time analyse the frequency composition from subsonic frequencies up to the audible range. To identify low-frequency sources or hums in particular, we use acoustic cameras that visualise the sound sources. In addition, we use microphones calibrated specifically for low-frequency noise according to DIN 45680 in order to capture even very low sound levels precisely.

Our services cover a wide range of applications:

• Industry and commerce: Here we measure machine noise, which often contains low-frequency components, and prepare reports on compliance with statutory noise protection requirements.
• Construction projects: For building projects, we check compliance with the limits according to DIN 4109, TA Lärm and DIN 45680, ensuring that permit procedures run smoothly.
• Residential areas: Frequent enquiries concern hums or traffic noise. We can analyse such low-frequency sources in a targeted way and locate their causes.
• Indoor spaces: We analyse disturbing low frequencies, for example from heating systems or electrical appliances, and develop individual noise reduction solutions.

Common noise sources in urban areas are air source heat pumps, wind turbines, combined heat and power units, biogas plants and air conditioning systems. Air source heat pumps and air conditioners produce constant noise from compressors and fans, while wind turbines cause “blade noise” through their rotors. Combined heat and power units and biogas plants produce engine and compressor noise. Traffic, especially lorries and buses, and construction noise also contribute considerably to urban noise exposure. Inside buildings, smaller electrical appliances such as fridges or exercise equipment (e.g. treadmills, ceiling fans) can also cause disturbing noise. All these sources influence the urban sound level and call for noise reduction and noise control solutions.

Thanks to modern sound level meters and frequency analysis software, we can locate noise sources even when they are behind walls. This technology is indispensable, especially for low-frequency noise such as hums. The results show in real time which frequencies (in Hz) are generated where and how strongly they are perceived (in dB). This data forms the basis for targeted noise reduction measures.

We offer both night-time and long-term measurements. These are particularly important for identifying sound sources such as low frequencies or subsonic noise that only occur at certain times. Long-term measurements record the noise level over several hours or days, enabling a detailed analysis of how the frequencies develop. This is relevant, for example, when night-time traffic noise or an intermittent hum is to be investigated.

Contact us by phone or email to arrange an appointment for a noise measurement. We first discuss the exact requirements, for example whether low-frequency noise such as hums or subsonic sources is to be analysed. You then receive an individual quote and we plan the measurement to suit your needs.