Headphone driver sizes typically follow a de facto standard, with 30mm, 40mm, and 50mm diameters being the most common. However, selecting the right driver size for a high-end headphone project can be challenging, as the performance data often doesn’t provide clear guidance.

While choosing a larger driver over a smaller one may seem like the obvious choice, the advantages are not always apparent in product specifications, which focus primarily on performance parameters like sensitivity and total harmonic distortion (THD).

This article delves into how a larger driver generally outperforms a smaller one in specific areas, such as Q factor control of the main resonator (F0), regional resonators within the driver, large signal THD, and intermodulation distortion (IMD). It also explains how to extract these insights using more advanced testing methods beyond just frequency response analysis.

To read the full paper, you can download it here.