As a person with normal hearing you can hear many different tones - low tones, mid tones, and high tones.

Most natural sounds consist of many tones which are present at the same time. You may call them harmonics.

Only if you are able to hear the whole symphony of tones - low, mid, and high - will the world around you sound most natural.

Experience description

What does it mean to hear only a certain portion of the tones which surround you? To find that out we have recorded three different scenes for you - a visit to a classical concert, a walk through a lively forest, and a quick stop at a busy cocktail party.

All three scenes differ in the quality of their original sound. In a concert, for example, many different instruments make up the rich sound of an orchestra. Each instrument activates a diffent range of tones. Octávio Inácio [1] showed that bass instruments like the contrabass start at very low tones, and the cymbals contribute to the highest tones heard in musical instruments (

When you chose a section from the world of sounds - low, mid, or high - we play a filtered version of the sound in which we removed all other tones. Although this is not meant to be a simulation of a hearing loss, you may get an impression of what it means not to hear all tones.

We have not filtered Bob's and Rose's voices. You can always hear their full range of vocal sounds, as for exapmle described by Nittayapa Klangpornkun [2]. Otherwise you would not be able to hear how they describe the different sound qualites as they perceive them. Try out how important mid and high tones are for speech understanding in the Magic Curtains.


  1. Octávio Inácio. (2005). FUNDAMENTALS OF ROOM ACOUSTICS, IACMA – International Advanced Course on Musical Acoustics Bologna, Italy, July 18-22, 2005.
  2. Klangpornkun N, Onsuwan C, Tantibundhit C, Pitathawatchai P. (2013). Predictions from "speech banana" and audiograms: Assessment of hearing deficits in Thai hearing loss patients. The Journal of the Acoustical Society of America 134(5):4132. DOI: 10.1121/1.4831179
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