Fig. 1 RHA Audio’s T10i

Metal Injection Moulding is being used by headphone manufacturers to create complex headphone housings that offer users significantly improved listening experiences. UK based headphone manufacturer RHA has introduced its flagship T10i headphone (Fig. 1), featuring the world’s first ergonomic, stainless steel driver housings for the mass market. The housing comprises two sections of injection moulded stainless steel (Fig. 2).

Fig. 2 T10i housings in the green (left) and sintered/polished state (right)

RHA states that MIM was the only way it could have achieved the ear contoured shape of the T10i in durable stainless steel. Not only is the T10i designed for comfort, but it is also has unique sonic and airflow properties ideal for functioning with the T10i’s handmade dynamic driver.

Following injection moulding, the parts are solvent and thermally debound prior to sintering. The combined housing pieces are then hand finished with a textured, brushed appearance to the stainless steel.

Fig. 3 Final Audio’s Heaven VIII headphone with MIM housing

Whilst the RHA headphones retail for around $200, audiophile headphones by Japan’s Final Audio Design can retail for up to $2500. In Final Audios’ products, MIM has enabled the freedom to design and manufacture internal forms that have considerable influence on sound quality, controlling elements such as resonance and air flow. The back of Final Audio’s Heaven VIII design, shown in Fig. 3, is reported to not only be for decoration, but resonance dispersion has also been factored into the design, making for a high-level balance between beauty and function.

In 2014 FloMet LLC, an ARCMIM Company, won an MPIF award for a group of MIM headphone components for US-based Sure Inc.