Enter room dimensions, pick a loudspeaker from the catalog and place it by click or automatically — sound-pressure heat map, speech intelligibility (STI) and 100 V power budget live, with parts list and CSV/IFC/BCF export. The same verified calculation as in the PlanWerke planner, to the parameters of DIN VDE 0833-4 (fire) or EN 50849 (other emergencies). Free, no sign-up, entirely in your browser.
Level in dB(A). Areas below the minimum level are dimmed, areas that are too loud (> 110 dB) are magenta.
Min.
0 dB
Average
0 dB
Max.
0 dB
Coverage
0 %
Effective minimum level: 75 dB (max. of the 75 dB target and 55+10 dB above ambient)
Uniformity (max − min): 0 dB
Loudspeakers
0
Connected
0 W
Amplifier
0 W
Reserve
0 %
100 V technology: recommended amplifier rating = connected power × 1.3 (reserve).
EN 54-24 data sheet
Generischer 100-V-Deckenlautsprecher, breite Abstrahlung (Innenräume).
Switch on to include the diffuse field (reverberation) and speech intelligibility (STI) in the evaluation.
None placed yet. Use “Place automatically” or click the plan.
The calculator handles a rectangular room. In the PlanWerke viewer you plan the voice alarm on your actual plan (PDF, DWG/DXF or IFC): detect rooms, place loudspeakers on an auto grid, heat map and power budget per storey — free during the beta.
Each loudspeaker contributes to the level at the listener via the distance law (rated sensitivity, connected power, distance); multiple sources are summed energetically. The check runs against the minimum level — default 75 dB(A) or ambient noise + 10 dB, whichever is higher.
With reverberation enabled, the calculator adds the diffuse field: reverberation time after Sabine from room volume and absorption, from that the critical distance and the speech transmission index (STI). The target is STI ≥ 0.5 — loud does not yet mean intelligible.
The placed loudspeakers yield the power budget of the 100 V system: connected power per amplifier line, recommended amplifier rating with a 30 % reserve and the parts list — exportable as CSV, IFC or BCF.
As target value the calculator uses 75 dB(A) or ambient noise + 10 dB — whichever is higher. 75 dB(A) is the conservative value for sleeping areas to the parameters of DIN VDE 0833-4; in general areas at least 65 dB(A) applies. Both targets can be adjusted in the calculator, and the heat map highlights under-covered areas immediately.
The speech transmission index STI (0–1) describes how intelligibly speech arrives at the listener — driven mainly by reverberation and background noise. The target is STI ≥ 0.5 (roughly CIS 0.7); from 0.62 the calculator rates intelligibility as good. A room can be loud enough and still unintelligible — which is why the calculator checks both.
The calculator uses the same loudspeaker catalog as the PlanWerke planner: generic 100 V types (ceiling, wall, horn, column) with documented datasheet values — rated sensitivity, power taps, coverage angle and measured directivity where maintained. The calculation runs locally in your browser; no data is transmitted.
Both, but for different cases: voice alarm systems for fire emergencies follow DIN 14675 and DIN VDE 0833-4, while sound systems for all other emergencies follow EN 50849 (successor of EN 60849). The calculator's targets (minimum level, STI) support both applications; the assignment is up to the qualified planner.
No. The result is a standards-oriented planning aid — a proposal for review by a qualified planner. Room geometry beyond the rectangle, fittings, frequency-dependent absorption and the on-site acceptance measurement remain with the professional planner; voice-alarm planning in PlanWerke is also marked as beta.
No account required · runs entirely locally in your browser