Ollo Audio S4R

The Ollo Audio S4R is a closed-back planar-magnetic headphone from the French brand Ollo Audio. It is designed for studio monitoring rather than casual bass-heavy listening.

A flatter response aims to make recordings easier to judge without strongly boosting bass or treble. That can help with mixing decisions, although the final result still needs checking on speakers and other headphones.

Closed-back ear cups reduce sound leakage and limit the amount of outside noise reaching the listener. This makes the design more practical for recording spaces and focused monitoring.

Planar-magnetic drivers use a thin diaphragm moved by magnetic force across a broad surface. In the S4R, that technology is paired with Ollo Audio's monitoring-focused tuning and closed-back construction.