The articulation of a headphone refers to the movement that allows a headphone to adjust its geometry to fit comfortably on the head. We usually find some height adjustment , rotation about a vertical axis and rotation about a horizontal axis. We are always researching ways to improve the articulation mechanisms. There are however inherent trade offs between comfort, acoustic / dynamic behaviour, cost and complexity.
There are many examples of headphones that don’t, strictly speaking, have articulation, instead the designer has allowed enough twist and flex in the headband so that the headphone sits comfortably on most people’s heads. The key to getting a design like this to work is getting the rest geometry just in the sweet spot for an average head. If the design is skewed to far in any direction, i.e. height, width, angles etc. there will be a large proportion of people who find the headphone fits poorly.
The classic swivel caliper design is the tried and tested go-to articulation mechanism. It offers great balance, the points of force application are all through the central axes, and in most cases allows for the largest range of motion. If in doubt use a swivel caliper.
The articulation mechanisms do directly impact the audio performance. At the basic level a proper articulation system ensures that all listeners get the same headphone fit and therefore a consistent acoustic system. When we look more closely at the dynamics of the articulation we will also find that the design of the articulation system will introduce a variety of resonant characteristics and proper care is needed to ensure that these characteristics are managed so that they dont negatively impact the audio performance