Acoustics of the Spherical Baffle

Traditional loudspeaker cabinets are almost always boxy. While a rectangular box is simple to manufacture, it introduces significant acoustic anomalies that degrade soundstage imaging. This article details the physics of speaker baffles and why Auralis designed the Atlas-2EYE around a spherical acoustic enclosure.

The Problem of Cabinet Edge Diffraction

When sound waves originate from a speaker driver, they travel outward across the front face (the baffle) of the cabinet. When these waves reach the edge of a flat rectangular baffle, they experience a sudden change in acoustic impedance. This causes the wave to scatter or "diffract" at the corners.

These diffracted waves behave as secondary sound sources, radiating out with a slight time delay compared to the direct sound from the driver. This interference leads to:

• Comb Filtering: Narrow peaks and dips in the frequency response.
• Smeared Imaging: The human brain relies on sub-millisecond arrival times to locate sounds. Edge diffraction confuses this mechanism, shrinking the perceived soundstage.

The Spherical Solution

A sphere represents the ideal acoustic baffle. Because a sphere has no sharp boundaries or corners, sound waves transition smoothly from the driver into the surrounding space. There is no sudden impedance mismatch, meaning edge diffraction is mathematically minimized.

Furthermore, a sphere is structurally the strongest geometric shape. Internal pressure waves are distributed evenly across the cabinet wall rather than flexing flat panels, eliminating cabinet resonance and boxy colorations.

Lab Measurements: Sphere vs. Box

Here is a simplified comparison of the frequency response deviations caused by cabinet diffraction:

Summary

By pairing our coaxial driver with a spherical baffle, the Atlas-2EYE functions as a true pulsating sphere—approaching the theoretical ideal of a point-source radiator. The result is a monitor that completely disappears in the room, leaving only a holographic, highly precise soundstage.