Introduction

64 Audio made a strong debut on TechPowerUp with its U18t flagship class IEMs, which were released over five years ago and use a whopping 18 balanced armature drivers per side. It also had a few of my favorite earphone features to date—namely, the tubeless in-ear audio (tia) driver for the higher frequencies and replacement pressure equalization modules that affected the seal and bass response. I mentioned in that review how I would love to see an excellent dynamic driver, such as the ECLIPSƎ driver in the DUNU ZEN PRO, paired with 64 Audio's tia driver in a hybrid configuration. Turns out the US-based company already had something up its sleeve, and thanks to 64 Audio for providing TechPowerUp a review sample!


Named the Duo, this offering from 64 Audio shies away from cramming in a large number of smaller balanced armature drivers and goes the route of dedicated acoustic chambers for the individual, larger drivers. The Duo is the most affordable of this series also comprising the $2300 Trió and $3600 Fourté, so you already know this is not a budget set, either. Announced during the height of COVID lockdowns, and work from home, the 64 Audio Duo is a semi-open set of IEMs meant to strike a cohesive balance between music enjoyment and working well for voice calls, and having them in the ears even if nothing is playing whilst aware of your ambient environment. This may sound hard to believe, but new technologies from 64 Audio, including LID, Wave Sync, and Apex Core, help out. We will explore all these new terms and more in this detailed review which begins with a look at the product specifications in the table below.

Specifications