Inside the TH1: Hemisphere™ Bearing

The Problem with Conventional Tonearm Bearings

There are countless philosophies in tonearm bearing design. Makers have experimented with exotic materials, ultra-high-precision machining, and minimizing contact patches — all in the pursuit of the best mechanical bearings money can buy.

But nearly all of these approaches rely on the same core principle: mechanical contact between two surfaces.

No matter how perfect the machining, there is always a physical coupling. And with that comes friction, wear, and transmission of unwanted vibration into the tonearm system. To solve these inherent flaws, air bearing tonearms were introduced.

Air bearings separate surfaces with a thin film of compressed air. With no contact between components, friction is eliminated. The stylus is free to trace the groove without interference from bearing chatter or stiction. Low-level detail retrieval improves, and mechanical noise is dramatically reduced.

That said, air bearing tonearms have usually been limited to linear-tracking designs, where airflow supports motion along a single axis. A few pivoted variants have existed — but none have implemented a true unipivot design.

Airon's Unipivot Air Bearing Solution

Airon Audio is proud to introduce the first unipivot air bearing tonearm. At the heart of the TH1 is the Hemisphere™ Bearing System — a fully pneumatic, contactless suspension system that enables pure freedom of movement in all directions.

Unlike linear air bearings, the Hemisphere system supports rotational motion around a single pivot point — without any mechanical contact. A custom-designed compressor delivers pulsation-free air to the bearing, ensuring that even microscopic disturbances never reach the stylus.

Thanks to its precision, the system is remarkably efficient. The bearing requires only 0.145 psi, or 0.996 kPa, of air pressure — less than it takes to blow a bubble through a straw.

How the Hemisphere™ Air Bearing Tonearm Works

The Hemisphere™ Bearing is a pneumatic pivot system based on two spherical surfaces: a convex “ball” and a matching concave socket. Both components are precision-machined to extremely tight tolerances.

Imagine placing a ball into a shallow, spherical cup. Now imagine that cup is a sealed, pressurized cavity. As air enters, it creates an invisible cushion between the two surfaces, lifting the ball just enough to eliminate contact.

The result is a thin, stable air gap — just 0.001 inches (25 microns) thick — that holds the tonearm in position while allowing smooth, frictionless movement in any direction.

There is no point contact, no bearing drag, and no mechanical resistance. The tonearm simply floats in place, perfectly balanced, and free to follow every nuance in the record groove — and because there is no contact between moving parts, the bearing will never wear out.

Watch the Hemisphere™ Bearing in Action at High End Munich 2025

Michael Fremer captures the mechanics up close at High End Munich 2025: Watch the video →