A universal IEM is designed to fit as many ears as possible using a standard shell shape and silicone or foam ear tips. A custom IEM (CIEM) is built from a precise scan or impression of your specific ear canal, so the shell is shaped exactly to your anatomy. The result is a fit that is airtight, stable, and consistent every time you put them in — no adjusting, no tips falling out, no variation in seal. Because the acoustic seal is more reliable, bass response and isolation are typically more consistent than with universals. CIEMs are also significantly more comfortable for extended wear, as there is no pressure from a tip being pushed against the canal wall. For musicians, performers, and dedicated listeners who spend long hours with IEMs in, the difference in comfort and reliability is substantial.

If you are in Sydney, we offer digital ear scanning in-house — just get in touch to book an appointment. Digital scanning is fast, clean, and produces highly accurate results that translate directly into 64 Audio's manufacturing process. If you are located outside of Sydney, you can have physical ear impressions taken by an audiologist. Please contact us and we will provide our audiologist guide, which outlines the specific impression technique and requirements that 64 Audio needs for the best possible fit result. Not all impression methods are the same, so following this guide is important.

64 Audio offers an extensive range of customisation options covering shell colour, faceplate design, and finish. Shell colours range from clear to solid colours and translucent tints, while faceplate options include a variety of wood veneers, carbon fibre, abalone, artwork prints, and premium designer finishes. You can also add custom engraving for names, logos, or artwork. Standard options are included in the base price, while certain premium finishes, materials, and artwork options carry an additional cost.

APEX — Air Pressure Exchange — is 64 Audio's patented venting technology built into every CIEM they make. A sealed IEM creates a pressure differential between the outside world and the ear canal, which over time causes listener fatigue and can lead to a feeling of discomfort or "ear pressure." APEX uses a small module with a controlled acoustic vent to continuously equalise that pressure, relieving the buildup without compromising the acoustic seal or meaningfully affecting isolation. In practice, listeners consistently report that 64 Audio CIEMs feel less fatiguing over long sessions than sealed customs from other manufacturers. Different APEX modules (m15, m20, mX) offer varying degrees of isolation, allowing you to tune how much ambient sound you let in depending on your use case — whether that's on stage, in the studio, or in daily life. Each module also has a subtle effect on bass response, meaning swapping modules is a simple way to adjust the overall sound character of your CIEM to suit your preference.

64 Audio backs every CIEM with a 30-day fit guarantee. If your customs do not fit correctly upon arrival, 64 Audio will remake them at no charge within that window. This covers cases where the shell is too tight, too loose, or causing discomfort due to a manufacturing fit issue. If you have any concerns about fit after receiving your order, contact us promptly so we can help manage the process with 64 Audio on your behalf.

Turnaround time is typically 6 to 8 weeks from when we receive your order. This can vary depending on seasonal factors — periods such as holidays and sale events tend to increase demand and may extend lead times beyond the standard window. We recommend factoring in some buffer if you have a specific date you need them by, such as a tour, event, or recording session. If timing is critical, get in touch and we can give you the most current estimate before you order.