Online calculators for voice evacuation and public address systems
Free online calculators for system designers and procurement teams: loudspeaker quantity and placement, amplifier power, cable sizing, backup power, and a full electroacoustic calculation with code-compliance checks. All calculations run in a single VPA calculator — below are the methods behind each one, plus a direct link to the tool.
Calculation methods
Electroacoustic calculation online
Sound pressure level, STI speech intelligibility and a compliance check against SP 3.13130.2026 (Russian fire-safety code) — the core calculation for design documentation.
Open →Loudspeaker quantity calculation
How many loudspeakers a room needs: based on floor area, ceiling height, dispersion pattern and zone coverage.
Open →100 V amplifier power calculation
Total load of the 70/100 V lines plus a 25% power margin — how to size an amplifier for a voice evacuation system.
Open →100 V line cable sizing
Voltage drop, line length and load, fire-resistant cable — how to calculate the conductor cross-section per GOST 31565 (Russian cable fire-safety standard).
Open →UPS and battery capacity calculation
Backup power for standby and alarm modes: power consumption calculation and battery capacity selection for a voice evacuation system.
Open →Outdoor civil alert system calculation
STI speech intelligibility ≥ 0.6 per GOST R 42.3.01-2021 (Russian civil alert standard): coverage calculation for horn loudspeakers and column speakers across open areas.
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