Worn-out ear pads often no longer fit properly on or over your ears – this not only makes the headphones less comfortable to wear, but also has a negative effect on sound quality. If ear pads no longer sit right and, as a result, the contact pressure is no longer optimally balanced, this has an audible impact on the sound. This is because over-ear headphones should firmly surround and enclose your ears, and on-ear headphones should rest perfectly on your ears and act as a tight acoustic seal. If that isn’t the case, then air can escape from the front of the enclosed space, which can lead to a consequent reduction in the amount of bass you hear: low-frequency sounds are then no longer directed straight into your ear, some of them get lost on the way. It is also possible that an ear pad’s foam filling changes over time, losing its shape or becoming softer. Putting your headphones on then serves to compress and compact the ear pads even more, affecting the sound across the entire mid-range and bass areas. In both cases, worn-out ear pads can result in very audible differences in sound quality, noticeably upsetting the proper balance between bass, mid-range and treble.