Perception of sound : how much does quality cost?

• Main Author: Lim, Miracle Joseph Jia Yi.
• Other Authors: PerMagnus Lindborg
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/54457
• Institution: Nanyang Technological University

The report shows results from an investigation into the perception of sound and explores the relationship between price and perceived quality of earphones. People tend to rate the quality of music listening experiences in terms of sonic clarity and envelopment [1]. Today, the most common situation where people listen to music is while commuting [2], however such environments are far from ideal because of the generally high ambient noise levels. In terms of price, people use a wide range of earphones, with correspondingly large variation in measurable audio quality (performance). Hypothesizing that price of earphones, satisfaction and listening experience quality are linearly related, investigation was done to see whether the price-quality relationship is moderated by different levels of ecologically valid ambient noise. A survey on listener habits on buses and trains in Singapore (N=100) was conducted and 5 typical earphone models were selected for the perceptual experiment (N=15). The selection of earphones was done through a series of technical tests done on the earphones in noisy and no noise environments. Volunteers listened to different kinds of music under 2 sound environment conditions: silent (in studio) and reproduced noisy commuter environments (≈ 75 to 85 dB(A)). The volunteers then evaluated the 5 models for which their acoustic performance were measured in terms of THD, frequency response, impedance and sensitivity. From the perceptual experiment, all participants showed a strong preference towards in-ear earphones and this can be attributed to the fact that in-ear earphones can isolate up to 14 dB of noise. Furthermore, from the sound quality test, it can be observed that 80% of participants were sensitive to the balance of sound coming into the left and right audio channels. The results will inform the development of ecologically valid simulations of how noisy environments affect people’s music listening quality. This will inform consumers as well as audio equipment manufacturers.