The Effects of Environmental Sound and Context on Listener Engagement with Speech-based Media

In the last 20 years the advent and growth in popularity of portable digital audio players, smartphones, and podcasting have contributed to the rise in popularity of mobile speech-based media consumption using auditory headset devices. But little is known about what impact a listener’s environmental context and the sounds contained within it have on their engagement with media. This thesis investigates how listener engagement with speech-based media is affected by surrounding environmental context, the sound that emanates from it, and the mediating effects that auditory headset devices have on listeners’ ability to perceive this sound. The results of an initial study on podcast listening behaviours identified 5 factors of environmental context that are capable of both positively and negatively affecting engagement. The Soundscape and at Work factor suggested that some listeners experience increased engagement with podcasts when listening in the presence of moderate or high levels of human or mechanical sounds. A study was then conducted to quantify the insertion loss and gain performance of three contemporary true wireless earbuds. The results found that all devices possessed a wide range of insertion loss and gain performance, with the most open hear-through modes significantly boosting external signals by as much as 15 dB, relative to open ear listening. The boosting was found to be centred around the frequencies considered most important to speech intelligibility. Finally, a listening experiment was conducted to investigate how different levels of environmental noise and boosting from hear-through modes affected listeners’ engagement with speech-based media consumed over earphones. The results showed that while increased exposure to noise resulted in lower engagement scores for most participants, the opposite was true for a small proportion of participants. The result suggest that adjustable hear-through in earbuds can provide listeners with an increased awareness of their surroundings, without compromising their engagement.