Headphones: The Perception and Measurement of Their Sound Quality
Sean E. Olive · Focal Press eBooks · 2025
When Todd Welti and I began our headphone research in 2012, there was little consensus on what makes a headphone sound good. This was reflected in the poor consistency and quality of headphones we measured, and the existing scientific literature and standards were being largely ignored, and for good reason: it was seriously flawed and outdated. So, we embarked on a 7-year research project to better understand the perception and measurement of headphone sound quality. This chapter summarizes what we and others have learned. The chapter is organized as follows: Section 15.1 discusses the psychoacoustics of headphones. Sections 15.2 and 15.3 explain why headphones have become so popular and what types are available. Section 15.4 examines the accuracy and consistency of headphone measurements made with different test fixtures and how they compare to measurements made on humans. The evolution of headphone calibrations proposed since the 1970s to the present are discussed in Section 15.5 . Section 15.6 summarizes the Harman headphone research from 2012 to present which identified a headphone frequency response or target curve that most listeners prefer. Three segments of listeners were found based on how much bass and treble they preferred added or removed from the target curve Section 15.7 summarizes three large surveys of headphones where measurements and predicted sound quality scores were presented: the results are not encouraging. Section 15.8 presents recent research where the Harman target curve was tested against other proposed targets. Section 15.9 summarizes the different versions of Harman targets, and Section 15.10 examines whether a different target curve is needed for spatial audio vs. stereo reproduction. Section 15.11 suggests where further research is needed, with conclusions drawn in Section 15.12 . There is much to discuss.