Etymotic ER4 SR/XR Noise-Isolating Earphones noise-isolating They are lovingly crafted with

They are lovingly crafted with only the finest components and manufacturing techniques

Premium earpads and ventilated suspension headband

Mundorf MLytic HV double-capacity electrolytic capacitors

it couldn't be easier

FULL METAL CNC SCULPTED CHASSIS

Etymotic ER4 SR/XR Noise-Isolating Earphones noise-isolating They are lovingly crafted withWhich ER4 is right for you? Both ER4 models, the ER4SR and ER4XR, use the same Balanced Armature (BA) drivers. The only difference is the tuning of the lower (bass) frequencies. The ER4SR, being the reference model, is tuned to be as precise and flat as possible. The ER4XR, being the fun model, is tuned with added bass. As you can see from the frequency response graphs below, ER4XR adds 1 2dB to the mid bass frequencies (below 200Hz) and 3 4dB to the