Page 62 - Spring2022

HEADPHONE SOUND QUALITY
Figure 2. The mean bass and treble levels and 95% confidence intervals for a headphone calibrated to match a flat in-room loudspeaker response. Each graph shows the interaction effect between the preferred levels and program, gender, listening experience, age, and the country of the test location (Olive and Welti, 2015).
preferred more bass and treble than their older, more expe- rienced counterparts. The older listeners (55+ years) were the exception here, preferring significantly more treble and less bass, consistent with their preference for headphone HP2. Altogether, these findings suggest that a single head- phone target may not be sufficient to satisfy variations in the recordings, individual tastes, listening experience, and hearing loss. A simple solution for headphone personal- ization is to provide a simple bass and treble control that allows listeners to compensate for these variations.
Testing the Harman Target with Larger Sample of Headphones
The next goal was to test the Harman target using a larger population of headphones. A total of 31 different head- phone models from 18 manufacturers were evaluated by 130 listeners, with an approximately equal number trained and untrained (Olive et al., 2018a). The head- phones ranged in price from $60 to $4,000, including open and closed back designs with dynamic or magnetic planar drivers. The same virtual headphone double-blind method was used to eliminate biases from visual and tactile cues.
The results establish that, on average, both trained and untrained listeners preferred the headphone equalized to the Harman target in 28 of the models tested. Four models with frequency responses close to the Harman target were equally preferred.
Segmentation of Listeners Based on Preferred Headphone Sound Profiles
Although the study established that listeners, on aver- age, preferred the Harman target to other headphones tested, it had not explored whether segments or classes of listeners exist based on similarities in their headphone preferences and what those sound quality features or profiles are. Also, it did not identify possible underlying demographic factors that might predict membership in each class. There was already prior evidence that younger males and less experienced listeners preferred higher levels of bass and treble in their headphones compared with females, experienced, and older listeners (Olive et al., 2013a; Olive and Welti, 2015). A reasonable hypoth- esis was that segmentation of headphone preferences may relate to bass and treble levels, possibly predicted by these demographic factors.
62 Acoustics Today • Spring 2022