Live sound tends to favour function over fidelity, but IEM experts 64 Audio place sound quality centre–stage.
While not entirely ubiquitous, in-ear monitoring is a commonplace solution for both pro and amateur stage performers' foldback requirements. Most IEMs use one or more 'balanced-armature' (BA) transducers, which comprises a tiny bar balanced about a pivot at its centre — hence the name. A permanent magnet creates a magnetic field which allows the bar to oscillate when an audio signal is passed through a coil of wire wrapped around one end of the bar. A lever attached to the other end transfers its movement to a diaphragm, generating the acoustic output.
Balanced-armature drivers are very power-efficient but have a restricted operating bandwidth, and so high-quality applications generally employ multiple BAs, each optimised to reproduce a different part of the frequency spectrum. Consequently, two, three or four-way systems are quite common. However, the subject of this review is 64 Audio's U12t in-ear monitor, which has 12 — yes, 12 — BAs in each earpiece. And if that's not impressive enough, the company also produce an 18–BA model!
64 Audio — formerly known as 1964Ears — are a family-run business based in Vancouver, Washington, and have been operating for about eight years now, producing a range of in-ear monitors suited to studio, stage and audiophile applications. The studio and stage models are designed to work with personalised custom ear moulds, while the audiophile models have universal-fitting push-on foam and silicon ear tips. However, the various bespoke technologies involved in the company's transducers are shared across the different ranges, which start with a two-driver system for £499 and extend up to an extraordinary 18-driver system, for £2999. There are also a couple of very special audiophile four-driver models costing over £3500.
For this review, I was sent the quite reasonable (in comparison!) U12t, model costing 'just' £1999. This is from the audiophile range and features a 12-driver design with universal ear tips; the studio and stage version of the same unit is called the A12t and it costs exactly the same. In fact the only differences between the U12t and A12t models are the custom ear moulds instead of removable universal ear...