Colour images 6 Human Factors in Design

Emotional experience of Frequency Modulated sounds:
Implications for the design of alarm sounds

René van Egmond, Delft University of Technology

Extra to paper in D. de Waard, K.A. Brookhuis, and C.M. Weikert (Eds.) (2004), Human Factors in Design (pp. 345 – 356). Maastricht, the Netherlands: Shaker Publishing.

Offset and onset envelopes

In this example the influence of the onset and offset envelope on the perceived character of the sound is presented.

 (mp3 file) A sine wave of 400 Hz without any envelope.

(mp3 file) A sine wave of 400 Hz with an offset envelope, this sine wave sounds like a struck guitar string.

(mp3 file) A sine wave of 400 Hz with an onset envelope this sound could be characterized as a clarinet (or a tone from a wind instrument).

(mp3 file) A sine wave of 400 Hz with an onset and offset envelope with again a different sound characteristic.

These examples show how important the onset and offset envelopes are and how they may influence the perceived character of the sounds.

Duration and frequency

 (wav file) Sine, 28 ms, 7600 Hz.

 (wav file) Sine, 28 ms, 1000 Hz.

 (wav file) Sine, 28 ms, 300 Hz.

(wav file) Sine, 28 ms, 100 Hz.

The character of these sounds ranges from rubber, wood, to metal, or glass like. These examples are used to show that the choice of a frequency is important to achieve a certain kind of sound feedback.


Roughness is an important perceptual aspect in the description of product sounds. Rough sounds can be generated using FM-synthesis (also combined with or without an amplitude envelope).

 (mp3 file) Rough.

(mp3 file) Not rough.

(mp3 file) Epilator.

Above sound files Rough and Not Rough have been synthesized using FM-synthesis. The sound file Epilator is the sound of a genuine epilator. Notice how rough the latter sound is.

Grid of modulation frequencies

Below the grid of FM-tones used in the experiment is shown. If you have Flash enabled click the image below and then click in the window and the animation will automatically play the examples. A complete description may be found in the book chapter.


For any further information on Product Sound Design and Perception at the TU Delft, please contact Rene Van Egmond.