Apr 18, 2017 · Tuning, enclosure design, and ear padding are everything when it comes to how drivers sound. Consider the following example. Audio-Technica makes two popular headphone models: The M50X and the M40X. The 50 uses 45mm drivers, and the 40 uses 40mm drivers. So you’d assume the 50X is better, since it uses bigger drivers, right? Not necessarily!