Apple was granted a new patent (filed in 2015) that details an audio device that uses a diaphragm made from a graphene-enhanced composite material. Apple's graphene membrane can be used in a speaker, microphone or headphone device. The patent specifically includes an image of an iPhone device as an example application.
Apple explains that as devices become smaller and lighter, it is ever more challenging to provide high quality audio using conventional materials - and graphene may improve the mechanical response of the audio device. In addition, in some cases, the use of graphene or graphene flake materials may reduce or eliminate the need for additional external damping.
It seems that the main invention here is that the membrane itself is made from two types of materials - which differ by the amount of graphene flakes used and thus the stiffness. The first portion of the membrane is fixed while the second portion is the flexible one that detects or produces sounds.
Graphene-based speaker applications have been under development for a long time. The earliest research we covered was in 2011 when researchers from Korea developed a transparent speaker made from Graphene. In 2013 graphene-based speaker that can outperform the best commercially-available earphones was demonstrated.
Fiio F3 graphene driver
Recently several companies released graphene-enhanced earphones. Xiaomi's Piston 3 Pro earphones, for example, make use of a graphene membrane, as does FiiO Electronics F3.
ORA GrapheneQ GO membrane
Israeli audio pioneer Waves Audio is developing an innovative electrostatic speaker using a nanoscale active membrane based on graphene. ORA, a Canada-based early-stage start-up that develops graphene-enhanced audio equipment, recently unveiled its graphene oxide-based composite material, dubbed grapheneQ.