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Improved conditions for better sound

Published: 21 January 2015

New research at Luleå University of Technology shows how perceived audio quality can be tested in a more efficient manner.
– When it comes to developing new technology, short production cycles are a fact. Hopefully my results can influence the listening tests so that they become more precise than before, says Jonas Ekeroot, Senior Lecturer in Audio Technology.

Photo: Jonas Ekeroot

When you are listening to music or speech, the device that plays the sound has been tested to insure that everything sounds as good as possible. It is called a listening test and means that during the manufacturing process people have been listening to different audio samples to determine if they sound good or not.

– My contribution when it comes to the listening tests is designed to make them more systematical than previously and to see if the selection process of audio samples can be done more efficiently, says Jonas Ekeroot.

Previously Jonas Ekeroot worked as a research engineer at Swedish Radio and there he performed lots of listening tests. He knows how difficult it is to select the appropriate audio samples for the tests. It is important that the audio samples stress the sound system and that they show clear differences between the unprocessed sound and sound that has passed through the system.

– This is called that the audio stimuli are critical. There is hardly any description of what that means and I myself have experienced how vague “critical” is. I've been thinking a lot about this and it led me to my research, says Jonas Ekeroot.

In his thesis Selection of Stimuli for Listening Tests by Software-Assisted Ranking, he has studied how people perceive sound quality. With the help of a computer program designed by himself he has asked 50 people to rank different sound examples based on how much difference they hear between the unprocessed and processed sounds.

He will make the software that he has developed available to everyone, as open source.

– Research is all about letting others know what you have done and sharing your results. We try to build knowledge together. I think it would be very interesting to see if others using the program get similar results.