Horn Speaker Acoustics

The Science of Horn Design

Horn speakers in early phonographs were not merely decorative elements but sophisticated acoustic devices designed to amplify sound efficiently. The exponential flare of the horn serves to match the high acoustic impedance at the diaphragm to the low impedance of free air.

Horn Geometry

The shape of the horn directly affects frequency response and efficiency. Key design parameters include:

• Throat Diameter: Determines the lower frequency limit
• Mouth Diameter: Affects high-frequency dispersion
• Flare Rate: Exponential curves provide best efficiency
• Length: Influences resonance characteristics

Material Considerations

Original horns were constructed from various materials, each with distinct acoustic properties. Brass horns offer bright, clear sound with excellent projection. Painted metal horns may have slightly different characteristics due to the paint layer. Wooden horns, though less common, provide warm, mellow tones.

Restoration and Maintenance

When restoring horns, preserve original acoustic properties by maintaining internal surface smoothness. Any dents or deformations can affect sound quality. For brass horns, polishing should focus on the exterior while preserving the interior's original finish, which may have developed beneficial acoustic characteristics over time.