Volume 13
The acoustic model utilizes the specific characteristics of the loudspeakers , including power and directivity , together with typical voice frequency characteristics .
Outdoor Acoustic Coverage
Designing outdoor systems requires taking into consideration all factors that affect outdoor acoustics including : wind effects , ground cover absorption , and barrier attenuation effects ( such as those posed by buildings and above-ground structures ).
GIS mapping of various layers is used to determine elevation heights of sound obstructions such as hills , mountains , high buildings , and other obstacles .
June 2017 Edition
A three-dimensional model of the actual facility and speaker locations is used to predict sound propagation , accounting for topographical features , buildings structures , ground and terrain effects , atmospheric effects , and geometrical spreading , and includes diffracted , direct and reflected sound paths .
This model is used to identify the optimum location of each outdoor speaker station to ensure clear , intelligible voice messages that could be heard throughout the area to be covered by the MNS .
ATI ’ s High-Powered Speaker Stations ( HPSS ) are used outdoors to provide the adequate acoustic coverage . Class D amplifiers for maximum intelligibility are being used .
Directional speakers are used to reduce echo and multiple arrivals of acoustic waves .
Indoor Acoustic Coverage
Indoor areas have different acoustic considerations .
Factors to be considered include the square footage of the building and layout , the shape of the space and the existing background noise level .
ATI Systems has worked with a large number of different types of indoor acoustic spaces including tunnels , industrial facilities and colleges , which include smaller rooms and hallways .
HPSS16 with bidirectional speakers
For communities , sound obstructions can be mainly obtained from GIS data .
For special facilities such as a military base or a campus , ATI utilizes various techniques to obtain structural heights .
The Control Station ( CS ) provides a centralized location for activating , controlling and monitoring all system equipment . The CS also has the ability to broadcast live public address , pre-recorded messages and siren tones .