
Etymotic ER4XR
The in-ear that defined 'flat' — and ten years on, the same graph reads as reference to some and bass-light to others.
1 review
Deep-insertion reference IEMs & hearing protection
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Etymotic (“true to the ear”) is an American engineering-driven research and manufacturing company founded in 1983 to build instruments for detecting and assessing hearing loss. It invented insert earphones in 1984 and, in 1991, introduced the first noise-isolating high-fidelity in-ear earphones using balanced-armature drivers — the ER-4 — effectively creating the modern in-ear monitor. It was acquired by Lucid Audio in 2018 and, in May 2026, by Fidelity Collective alongside Westone Audio.
Prices in USD, recorded when each review was updated.