TUNNELS
The acoustics of tunnels require specialised solutions for evacuation and voice alarm systems, both to ensure the intelligibility of the messages transmitted and to overcome the ambient noise and confusion inherent in these situations. In addition, the length of the tunnels requires the distribution of power units and their networking, the synchronisation of the transmission of warnings and the acoustic processing of audio signals with filters and delays.
Key functions
- Demanding acoustics: The very shape and architecture of the tunnel, as well as the hard surfaces, often the rock itself, cause high reverberation and make it difficult to understand messages.
- High ambient noise levels: Traffic noise and ventilation systems affect the clarity of messages delivered by the loudspeakers.
- Specialized design: Due to sound dispersion and interference from reflections, among other factors, it is very difficult to achieve correct intelligibility with a conventional sound system.
- Strategic speaker placement: Because they are placed throughout the tunnel and separated by great distances, it is essential to calculate the position of each speaker and adjust the audio signal delay to ensure message intelligibility.
Key features
- Adequate acoustic coverage: The dispersion of the loudspeaker's acoustic beam must minimize reverberation and maximize intelligibility, avoiding ceiling bounces and adequately covering the entire tunnel and vehicles traveling in any direction.
- Signal optimization: Application of technologies to adjust equalization and improve message clarity, usually with DSP (Digital Signal Processor) functions that include filters and delays designed for each situation.
- Environmental adaptability: Solutions designed to withstand extreme conditions of humidity, dust, and temperature, especially in loudspeakers but also in other auxiliary equipment such as intercoms in refuge areas or access to intermediate tunnel exits.
- Specialized loudspeakers: Built to withstand corrosive atmospheric contaminants, high levels of humidity, and extreme temperatures (from -25º to +70º C), very high SPL level, balanced frequency response and very low distortion.
Benefits
- Safety and risk prevention: An adequate public address system allows effective communication in emergency situations, facilitating evacuations and rapid responses. In addition, it prevents incidents by transmitting clear and timely information to users.
- Improved user experience: Understandable and well-distributed messages allow for smooth orientation within the tunnel, reduce confusion, and improve the safety of drivers and pedestrians.
- Operational efficiency and connection with other systems: The integration of the public address system with other security systems, such as fire detection, ventilation, and emergency signaling, optimizes tunnel management and improves the coordination of incident responses.
