tunnehäälte

Tunnehäälte is a term used in acoustics to describe the distinctive sound field produced by long, enclosed tunnels. It denotes the pattern of reflections, diffusion, and modal resonances that shape how voices, announcements, and music are heard inside such environments. The term is a neologism that appears primarily in niche acoustic literature and is most commonly discussed in the context of transit systems in Europe and North America.

Physically, tunnehäälte features extended reverberation times, pronounced low-frequency content, and prominent flutter echoes along straight sections. The tunnel’s cross-sectional shape, lining materials, and the presence of ventilation ducts influence the spectral balance and decay rates. Smoother, harder surfaces tend to increase reverberation, while porous linings dampen it. Geometry, curvature, and transitions produce modal patterns that can cause focal points of amplification and time-domain coloration.

Measurement and modeling rely on impulse responses, sine sweeps, MLS tests, and computational methods such as ray tracing and wave-based simulations. RT60 values for large transit tunnels commonly range from about 1.5 to 3 seconds, depending on length, cross-section, and lining. Real-world measurements must contend with traffic, train passages, and ventilation noise.

Applications include the design of public-address and emergency-communication systems, sound-design for signage, and artistic installations that exploit tunnel acoustics. Ongoing research investigates how tunnehäälte interacts with operational noise and crowding, seeking to improve intelligibility, safety, and occupant comfort.