ER4S

About the ER4S

The Etymotic Research ER4S are high-precision, balanced armature in-ear earphones known for their ultra-lightweight design and exceptional noise isolation of up to 42dB. They deliver a transparent, reference-quality sound with enhanced bass and high-frequency output, making them ideal for home stereo, computer use, and portable audio devices. The ER4S features custom removable filters for frequency response shaping and earwax protection, foam and plastic flange eartips for comfort and sound isolation, and a 5-foot cable with a 3.5mm stereo plug and 1/4" adapter. They are favored by musicians, recording engineers, and audiophiles for their accurate, real-ear response and ability to reproduce music with clarity and naturalness at safe listening levels. Each pair is precision matched and assembled in the USA, with a frequency response of 20 Hz to 16 kHz, 100 Ohms impedance, 108 dB sensitivity, and maximum output of 122 dB SPL. The package includes multiple eartips, replacement filters, a filter changing tool, shirt clip, carrying pouch, and storage box.