Simplex 4906-9154 — a ceiling-mount TrueAlert speaker/visible (S/V) notification appliance combining a multi-tapped speaker with a multi-candela synchronized xenon strobe, in a white housing with red FIRE lettering printed on two sides.
This is the non-addressable ceiling S/V in the TrueAlert multi-candela family. The speaker side is multi-tapped for 1/4 W, 1/2 W, 1 W or 2 W at either 25 VRMS or 70.7 VRMS, with a capacitor input for connection to supervised audio circuits, and it meets the NFPA 72 520 Hz low frequency signal requirement for sleeping areas. The strobe side is a regulated 24 VDC xenon strobe whose intensity is set in the field to 15, 30, 75 or 110 candela using a selection plug at the back of the housing; an attached flag with black letters on a highly visible yellow background shows the selected setting at the side of the lens. Because a single model covers four candela ratings, on-site inventory stays small and changes during construction are easy to absorb. Speaker and strobe are wired separately, and the strobe is driven from a NAC configured for the Simplex synchronization format or from a separate synchronization module, so that multiple visible strobes flash together. The housing is rugged, high-impact, flame-retardant thermoplastic, impact and vandal resistant.
Specifications
| Device type |
Non-addressable ceiling-mount speaker/visible appliance with multi-candela synchronized strobe |
| Housing and lettering |
White housing, clear lens, red FIRE lettering printed on two sides |
| Strobe candela settings |
15 cd, 30 cd, 75 cd or 110 cd, field selectable |
| Strobe rated voltage range |
Regulated 24 VDC; 16 VDC to 33 VDC |
| Flash rate and NAC loading |
1 Hz, with up to 35 synchronized strobes maximum for each NAC |
| Maximum RMS strobe current (nameplate) |
15 cd: 80 mA · 30 cd: 127 mA · 75 cd: 269 mA · 110 cd: 371 mA |
| Reference RMS strobe current at 24 VDC |
15 cd: 50 mA · 30 cd: 83 mA · 75 cd: 155 mA · 110 cd: 211 mA |
| Reference RMS strobe current at 18 VDC |
15 cd: 67 mA · 30 cd: 111 mA · 75 cd: 207 mA · 110 cd: 281 mA |
| Speaker input voltage |
25 VRMS or 70.7 VRMS |
| Speaker power taps |
1/4 W, 1/2 W, 1 W and 2 W |
| Speaker output (UL 1480 reverberant chamber test, at 10 ft / 3 m) |
1/4 W: 76 dBA · 1/2 W: 79 dBA · 1 W: 82 dBA · 2 W: 85 dBA |
| Fire alarm frequency response |
400 Hz to 4000 Hz |
| Polar dispersion (anechoic, per ULC-S541) |
-3 dB at +/- 30° off-axis; -6 dB at +/- 55° off-axis |
| Housing dimensions |
Speaker housing 7-1/2 in. (191 mm) diameter, 1/2 in. (13 mm) deep; lens protrusion 2-5/8 in. (67 mm) above the speaker housing; depth into the box 2-3/4 in. (70 mm) |
| Environmental |
32°F to 122°F (0°C to 50°C); 10% to 93% RH, non-condensing at 100°F (38°C) |
| Connections |
Terminal blocks for 18 AWG to 12 AWG (0.82 mm² to 3.31 mm²), two wires per terminal for in/out wiring |
| Mounting |
4 in. electrical box with an extension |
| Listings |
Speaker UL listed to Standard 1480 and ULC-S541; strobe UL listed to Standard 1971 and ULC-S526. The 4906-9154 carries the UL listing; the 4906-9157 is the ULC listed equivalent. FM approved, CSFM listed, MEA (NYC) acceptance |
Installation notes
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Size the NAC from the maximum RMS rating, not the 24 VDC figure. Johnson Controls notes that the strobe design is constant wattage, so the maximum RMS current occurs at the lowest allowable operating voltage — 371 mA at 110 cd is the nameplate rating that circuit calculations must respect.
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Synchronization source: strobes are activated from NACs selected to provide Simplex strobe synchronization signals, or from separate synchronization modules — 4905-9914 for Class B and 4905-9922 for Class A operation. See data sheet S4905-0003.
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35 strobes per NAC is the synchronized maximum.
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Separate circuits: the speaker is wired separately from the strobe. The speaker connects to conventional fire alarm audio circuits through its capacitor input.
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Set the candela before you close it up: the selection plug sits at the back of the housing, and the yellow flag showing the selected intensity is readable at the side of the strobe lens after installation.
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Anechoic versus reverberant ratings: the manufacturer notes that anechoic speaker output ratings are typically more representative of actual installed sound output than the reverberant chamber figures.
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Application selection: correct visible notification depends on occupancy, location and local codes — apply NFPA 72, ANSI A117.1, the governing model building code and the ADA guidelines.
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Suspended ceilings: the 2905-9946 tile bridge is available for ceiling-mount installations.
Related models
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4906-9157 — the ULC listed ceiling S/V, white with red FIRE lettering
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4906-9158 — ceiling S/V with red ALERT lettering instead of FIRE
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4906-9159 — ceiling S/V with a blank (unlettered) housing
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4906-9160 — ceiling S/V with a red housing and white FIRE lettering
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4906-9151 / 4906-9153 — the wall-mount versions of this appliance, red with white lettering and white with red lettering, 7-1/4 in. x 5 in. x 2-5/8 in.
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2905-9946 — tile bridge for ceiling installations
Specifications taken from the Johnson Controls / Simplex data sheet "TrueAlert Multi-Candela Notification Appliances — Visible Notification Appliances with Speaker and Multi-Candela Strobe; Non-Addressable," document S4906-0003 Rev. 12 (2/2026). Manufacturer specifications are subject to change without notice.
