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Much more than just a nuisance


Noise is disturbing or annoying, unwanted sound (background noise).

A number of studies have been carried out on the effects of noise. These are just a few examples:

Sust / Lazarus (2002)

In the research report FB 794 of the Federal Institute for Occupational Safety and Health (BAuA), Dipl.-Psych., Dipl.-Päd. Ch. A. Sust and Prof. Dr.-Ing. Lazarus deal with the "Effects of noises of medium intensity on simulated office and screen activities of varying complexity". Extensive tests were carried out for this purpose.

The most important results:

Sounds with relatively high intensity and information content significantly impaired the performance of the test subjects. As the complexity of the tasks increased, this effect intensified. This resulted in higher time requirements and a higher frequency of errors - but also in an increased need to recover. Altogether it could be stated that more time was needed for the reaching of the work goals. More frequent checks were necessary and tasks had to be restarted several times. Where complex tasks had to be completed, the test persons even tended to omit or cancel the processing of the tasks incompletely.

Sound is characterized on the one hand by its volume (sound pressure) and on the other hand by its pitch (frequency). In this case, noises in a frequency range between 2,000 and 5,000 Hz with the same sound pressure are subjectively perceived as considerably louder than noises below or above this frequency range. This means that speech can drown out other sounds, even if physically both types of sound are equally loud.

Evans and Johnson (2000)

G. W. Evans and D. Johnson published a study entitled "Stress and noise in open offices" in which they examined the stress-inducing effects of noise. The study was published in the Journal of Applied Psychology 2000/85(5), pp. 779 - 783.

The most important results:

At the end of a three-hour office session, the levels of the stress and steroid hormones adrenalin, noradrenalin and cortisol in the urine of 20 participants were measured. The researchers from the USA found that participants who previously performed their tasks at an average office noise level of 55 dB(A) had a significantly higher adrenaline level than participants who worked in a noiseless situation. The release of noradrenaline and cortisol was obviously not affected. The typing speed, which was used as an indicator for work performance, also did not decrease. However, the researchers observed that the louder environment caused the test persons to freeze. Those participants who worked with a noise level of 55 dB(A) changed their posture during work only half as often as the persons in the comparison group. In particular, they refrained from adjusting their chairs, monitors and keyboards.

Physiologische und nicht-physiologische Änderungen durch Bürolärm (im Vergleich zur Ruhebedingung). N = 20; n.s. = nicht signifikanter Unterschied. Die Einheiten der y-Achse sind in [eckigen Klammern] angegeben. Quelle: Evans und Johnson (2000)
Physiologische und nicht-physiologische Änderungen durch Bürolärm (im Vergleich zur Ruhebedingung). N = 20; n.s. = nicht signifikanter Unterschied. Die Einheiten der y-Achse sind in [eckigen Klammern] angegeben. Quelle: Evans und Johnson (2000) Lupe_grau

Klatte, Bastian, Meis et al. (2007)

M. Klatte, J. Bastian, M. Meis and B. dealt with the effects of noise on mental activities. Noack. Title: "Effects of background noise and reverberation on speech understanding and working memory in different age groups" published in Fortschritte der Akustik. Contributions to the 33rd Annual Conference on Acoustics, DAGA 2007, Stuttgart.

The most important results:

The group of researchers from Eichstätt and Aachen studied the influence of language on cognitive performance. For this purpose, 20 test persons should, for example, remember series of numbers while they listened to speech with irrelevant content. The results showed that volume of the speech (35 or 55 dB) had a clear influence on the perceived level of annoyance. It could be reduced by lowering the volume. In order to reduce the error rate, however, it was not sufficient to only reduce the volume. Only a reduction in speech intelligibility could also significantly reduce the error rate.


All three of these studies, and several others, show that unwanted speech noise leads to stress and reduced performance. In addition, people exposed to noise give up more quickly on difficult tasks and move less. The studies also show that it is not enough to reduce the volume of speech sound. At the same time, speech intelligibility must be reduced through appropriate measures.

In the showrooms the IBA Forum you will also find solutions for better acoustics.