What are the acoustic properties of stone versus concrete in outdoor amphitheater seating?

When designing an outdoor amphitheater, the choice of seating material significantly impacts acoustics. Stone and concrete are common options, each with distinct acoustic properties.

Stone Seating:

Stone, such as granite or limestone, offers excellent sound reflection due to its dense, non-porous nature. This creates clear, bright acoustics with minimal sound absorption, making it ideal for open-air venues where sound projection is key. However, stone can produce harsh echoes if not properly shaped or spaced.

Concrete Seating:

Concrete provides a balance between reflection and absorption. While less reflective than stone, its slightly porous surface reduces high-frequency echoes, resulting in warmer sound quality. Precast concrete can also be molded into optimized shapes for better sound dispersion.

Durability & Maintenance:

Both materials are durable, but stone may require more upkeep to prevent weathering effects on acoustics. Concrete is often more cost-effective and easier to shape for acoustic tuning.

For optimal acoustics, consider combining materials or using textured surfaces to control sound reflection in outdoor amphitheaters.