Etymotic ER4 SR/XR Noise-Isolating Earphones (Open Box) Model:ER4SR Studio Reference given the space to grow

given the space to grow and shine

this development was not easy

you are left with what some are calling the most comfortable headphone around

Delivers dense sound teeming with realism

Wireless Noise Cancelling Headphones

Etymotic ER4 SR/XR Noise-Isolating Earphones (Open Box) Model:ER4SR Studio Reference given the space to growWhich 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