At the Rocky Mountain Audio Fest 2018 Sony announced two Signature Series personal audio products: the DMP-Z1 digital music player/headphone amp/DAC and the IER-Z1R universal-fit earphone reviewed here. New Sony Signature Series models don’t come along all that often, so when they do we naturally stand up and take notice.
The IER-Z1R represents a serious effort to create a state of the art earphone. As Sony acoustic engineer Eiji Kuwahara puts it, “You expect just an in-ear headphone, but you’re in for a surprise… Music sounds live. It spreads out in front of you, it’s real.” The IER-Z1R is based on what Sony terms an 'HD Hybrid Driver System' consisting of a 12mm dynamic mid-bass driver with a magnesium diaphragm, an all-new Sony balanced armature tweeter, and a 5mm dynamic super‑tweeter.
The 12mm driver loads into a magnesium housing with an extended acoustic cavity to its rear, which is fitted with an acoustic tube that acts as a tuning device. The 5mm super-tweeter is positioned coaxially to the earphone’s sound outlet nozzle and offers, says Sony, “frequency response up to 100kHz.” Design goals included absolute consistency of voicing and phase coherency between the drive units, with the intent of having them sound, “as though they were a single, ideal driver.”
These gorgeous earphones feature mirror-polished outer housings made of a zirconium alloy, with rear covers featuring delicate, engine-turned surfaces. Thoughtful accessories include a wide array of ear tips, plus two high-quality signal cables (one single ended, the other balanced).
For my tests I drove the IER-Z1R’s from an Astell&Kern A&ultima SP1000M DAP (using single-ended cables) and a Woo Audio WA11 Topaz balanced headphone amp/DAC (using balanced cables). Reference earphones included the Campfire Audio Solaris and AKG N5005.
Straight from the box the IER-Z1R’s sounded extremely crisp, precise, and sharply detailed—almost to a fault. However, as playing time accumulated (20+ hours) the sound smoothed noticeably, becoming richer, warmer, more relaxed, and more natural. While hardcore detail fanatics might actually prefer the IER-Z1R’s pre-run-in sound, I think music lovers who appreciate a naturally accurate and unforced presentation will love how the IER-Z1R evolves over time. Once the IER-Z1R has been run-in its sound offers three defining characteristics.
The first characteristic is powerful, articulate, and deeply extended bass—a quality that becomes apparent on everything from pipe organs, tom toms, kick drums, concert bass drums, bass synths, and electric and acoustic basses. For example, the IER-Z1R lets you feel and hear the textures and plunging low-frequency energy of the descending bass guitar glissandos on Billy Idol’s 'Prodigal Son' [Prodigal Son, Chrysalis, 16/44.1]. Stated simply, the Sony IER-Z1R offers the best bass I have yet heard from any earphone.
The second characteristic is an accomplished midrange that is smooth, yet also richly detailed, and full of subtlety and nuance. Unlike some earphones that shine a bright, penetrating spotlight on musical details, the IER-Z1R instead lets details unfold in a gracious, organic, and natural way, which I found more satisfying in the long run. As a result, the IER-Z1R invites the listener to drink in complex midrange sounds—such as Yuri Honing’s intensely evocative saxophone solo as heard on 'Walking on the Moon' from The Yuri Honing Trio’s Star Tracks [Jazz in Motion, 16/44.1]. There, the IER‑Z1R’s nuanced presentation made Honing’s saxophone sound dynamically alive—and very nearly real.
The third characteristic is masterful rendition of reverberant information and spatial cues in recordings, which enables the IER-Z1R to produce huge, 'outside-the-head' soundstages. This quality proved stunning on Elvis Presley’s 'Fever' from Elvis Is Back [Sony Legacy, 16/44.1]. Specifically, the earphones neatly exposed the amounts and types of reverb applied to Elvis’ vocals throughout the song, while showing how widely spaced percussion instruments define the boundaries of the soundstage through sounds that reverberate and linger on the air.
In sum, Sony’s IER-Z1R is a true, world-class earphone that sounds even more beautiful than it looks. Is it the best of the best? It is certainly in the running for top honours, though only you can decide if it qualifies as your 'personal best.'
IER-Z1R universal-fit earphone
Type: Hybrid Drive universal-fit earphone
Driver complement: One 12mm dynamic mid-bass driver with magnesium diaphragm, one newly developed Sony balanced-armature tweeter, and one 5mm dynamic super-tweeter.
Frequency Response: 3 Hz to 100kHz
Impedance: 40 Ohms
Weight:. 26 g, not including cable
Accessories: Garment clip, carrying case, cleaning cloth, two 1.2 m detachable signal cables (one balanced, one single-ended) with silver-coated OFC conductors, seven pairs of hybrid ear tips (sizes SS, S, MS, M, ML, L, and LL), and six pairs of triple comfort ear tips (sizes SS, S, MS, ML, and L)
Price: $1,999 US, £2,000
Manufactured by: Sony