Over 30 years ago, Etymotic invented noise-isolating,
in-ear earphones. Etymotic’s original design, developed
for auditory research and hearing testing, used balanced –armature receivers and established these speakers as the gold
standard for high-definition, in-ear earphones. ER4 earphones were the first
high-fidelity, noise isolating in-ear earphones to use this technology in a
consumer earphone, and are recognized as the world leader for response accuracy
to which all other earphones are compared.