This is extremely important in AV acoustic design because wavelength determines:

• Speaker spacing

• Phase interaction

• Room modes

• Acoustic treatment thickness

Types of Sound Waves

Longitudinal Waves

Sound propagates parallel to particle motion.

Example:

• Air sound waves

• Loudspeaker output

Spherical Waves 

• From a point source sound spreads in all directions.

• Used in room acoustic modeling.

Plane Waves

• Sound propagates in a single direction with flat wavefronts.

• Used in waveguide and line array theory.

Sound Propagation in Different Mediums

Reason: particle density and elasticity.

Wave Behaviors in Rooms (Important for AV Engineers)

When sound propagates in rooms, waves interact with surfaces.

Reflection

Sound bounces from surfaces.

Used in:

• concert hall design

• room acoustics

Diffraction

Sound bends around objects.

Important for:

• speaker placement

• coverage prediction

Absorption

Materials convert sound energy to heat.

Used in:

• acoustic panels

• bass traps

Interference

Two waves combine.

Results:

• constructive interference

• destructive interference

Critical in:

• line array tuning

• multi-speaker systems

Practical Example (AV System Design)

In sound system design (EASE / AV modeling) wave theory helps determine:

• speaker spacing

• phase alignment

• delay settings

• room mode frequencies

• coverage prediction

• acoustic treatment thickness

Example:

Low frequency 100 Hz, Wavelength ≈ 3.4 m

So acoustic treatment must be ~0.8–1 m thick to fully absorb it.

Sound propagation = Energy traveling through particle vibrations forming pressure waves in a medium.