Issue link: http://read.uberflip.com/i/324330
2014 Loudspeaker Industry Sourcebook 22 INDUSTRY REPORTS Figure 3 shows the mean preference ratings for 218 listeners grouped according to their listening experience (trained vs. untrained), country of residence, and age (students vs. post-college listeners). Two conclusions can be drawn from this data. First, based on sound quality, the same headphones are preferred regardless of the user's listening experience, age, or country of residence. Second, the trained listeners tended to provide more discriminating and consistent ratings as a group compared to the untrained listeners. This behavior is consistent with previous studies that compared trained and untrained listeners. Subjective Ratings of Headphone Sound Quality So far, our studies have only focused on how the headphone's frequency response influences its perceived sound quality, without considering other factors (e.g., nonlinear distortion). While the research is ongoing, there are strong correlations between the headphone's frequency response and its overall perceived sound quality rating. The more preferred headphones tend to have frequency responses that are smooth, free of resonances, and approximate the target response an accurate loudspeaker measured in a reference listening room. It is also clear that frequency-response measurements must include leakage effects related to the headphone's fit to accurately predict listeners' sound quality ratings. Scientific Evidence Together, these studies provide scientific evidence that when brand, price, fashion, and celebrity endorsement are removed from subjective evaluations, listeners generally agree on what makes a headphone sound good. So far, this has been true regardless of users' listening training, age, or culture. The more preferred headphones tend to have a smooth, extended frequency response that approximates an accurate loudspeaker's in-room response in a reference listening room. This new target frequency response could provide the basis for a new and improved headphone target- response curve. LIS Reference  Future Source Consulting, "Headphone Market to Exceed $8 Billion in 2013," November 2013, http://futuresource-consulting.com/2013- 11-headphones.html. Resources F. Fleischmann, A. Silzle, and J. Plogsties, "Identification and Evaluation of Target Curves for Headphones," presented at the 133 rd AES Convention, October 2012. G. Lorho, "Subjective Evaluation of Headphone Target Frequency Responses," presented at the 126 th AES Convention, May 2009. S. Olive, "Some New Evidence that Teenagers and College Students May Prefer Accurate Sound Reproduction," presented at the 132 nd AES Convention, April 2012. S. Olive and T. Welti, "The Relationship between Perception and Measurement of Headphone Sound Quality," presented at the 133 rd Audio Engineering Society (AES) Convention, October 2012. S. Olive, T. Welti, and E. McMullin, "Listener Preferences For Different Headphone Target Response Curves," presented at the 134 th AES Convention, May 2013. S. Olive, T. Welti, and E. McMullin, "A Virtual Headphone Listening Test Methodology," presented at the 51 st AES International Conference, August 2013. S. Olive, T. Welti, and E. McMullin, "Listener Preferences for In-Room Loudspeaker and Headphone Target Responses," presented at the 135 th AES Convention, October 2013. Figure 3: The mean preference ratings of three popular headphones (the HP1, the HP2, and the HP3) and one equalized to the HARMAN target response was provided by different groups of trained and untrained listeners.