Etymotic Research ER4SR Reference Earphones Sennheiser Our patented algorithm perfectly compensates

Our patented algorithm perfectly compensates for the internal delay generated by a noise cancellation loop

the Sundara is priced as an entry-level music lover's headphone

We've used high-purity OFC silver coated cables that provide a wide sound stage

our premium wireless speaker delivers room-filling sound from a single source

Etymotic Research ER4SR Reference Earphones Sennheiser Our patented algorithm perfectly compensatesOverview ER4SR is the highest performing single driver in ear monitor. The IEM shells are made of anodized aluminum, CNC machined with extremely tight tolerances. Using a single Balanced Armature (BA) driver allows for extremely accurate IEM without the added complexity of crossovers, and helps keep the aluminum body small and slim. The included high quality user replaceable cable is reinforced and twisted, to improve longevity and durability.