Most PA systems in Bangladesh are either too quiet to hear or too loud to understand. This page shows you how to size speakers and amplifier power for your building, why 100V line changes everything, and the six mistakes that produce an unintelligible system.
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Ceiling-speaker method: seated ear height 4 ft, 90° dispersion, 100 V line taps, 25% amplifier headroom.
The headline product is rarely more than half the installed cost. These are the parts that get left out of budgets.
The core. 100V line output, with microphone and music inputs. Size at 130% of total speaker load.
Ceiling, wall, horn or column depending on the space. Each tapped to a wattage.
Desk or gooseneck at reception or the security desk. Priority over music.
Two-core, correctly sized for the run length. 100V line tolerates long runs but not undersized cable.
Announce to one floor or one department instead of the whole building. Essential above about three zones.
Fire alarm override that cuts music and plays evacuation announcement. Often a code requirement.
Retail and hospitality. Keep it on a separate input so paging can override it.
Uses existing network instead of dedicated speaker cable. Better for multi-building or campus sites.
An emergency announcement system that dies with the mains is not an emergency system.
The honest trade-offs.
| Consideration | Ceiling Speaker | Wall / Box | Horn Speaker | Column Speaker |
|---|---|---|---|---|
| Coverage pattern | Downward cone | Directional | Long throw | Narrow vertical |
| Typical power tap | 3–10 W | 5–20 W | 15–50 W | 10–40 W |
| Speech clarity | High | Good | Moderate | Highest |
| Outdoor / weather | No | Some models | Yes | Yes |
| Appearance | Flush, discreet | Visible | Industrial | Slim |
| Typical use | Office, hotel, hospital | Corridor, retail | Factory, outdoor, yard | Mosque, hall, reverberant space |
| Relative cost | Moderate | Lowest | Moderate | Highest |
Ceiling height drives everything. A speaker at 10ft covers roughly 150 sq ft with good clarity; at 20ft it covers more area but intelligibility drops sharply. High ceilings usually need horns or columns, not ceiling speakers.
Cable runs and gauge. 100V line tolerates long runs, but undersized cable still causes voltage drop and quiet speakers at the far end. Size the cable to the run, not to the connector.
Reverberation. Hard floors, glass and bare concrete create echo. In these spaces more power makes intelligibility worse, not better — you need directional speakers instead.
Zone planning. Decide zones before cabling. Retrofitting zone separation into a single-loop installation means pulling new cable.
Ambient noise measurement. A factory floor at 85 dB needs announcement at roughly 95 dB to be understood. Measure it rather than estimating.
Fire alarm interface. If the system doubles as emergency announcement, the fire panel interface must be specified at design stage. Retrofitting is expensive.
Power consumption is modest. A PA system idles at very low draw and only pulls its rated power during announcements. Over a year it is a minor electrical load.
Speaker lifespan is long. Passive speakers with no moving electronics typically last 10–15 years indoors. Outdoor horns degrade faster from sun and rain — budget replacement at 5–7 years in exposed positions.
Amplifier is the wear item. This is where failures happen, usually from running consistently near maximum. An amplifier sized with 30% headroom lasts substantially longer than one running at 95%.
Microphone capsules degrade with handling and humidity. Budget replacement every few years on heavily used paging positions.
The cost people do not anticipate: re-doing a system that was never intelligible. Undersized amplifiers, wrong speaker type for the acoustics, or speakers spread too thin produce a system nobody can understand — and the only fix is replacement. Sizing correctly the first time is far cheaper than the alternative.
Every one has cost a real project real money.
Limits you to a few speakers and short cable runs, and every added speaker changes the load on the amplifier. It is the wrong architecture for a building.
Do this: 100V line for any multi-room or multi-floor installation. Non-negotiable.
An amp at 95% load runs hot, distorts on peaks and fails early. Distortion is also what makes announcements unintelligible.
Do this: Size the amplifier at 130% of total speaker load. The calculator above includes this.
Fewer speakers turned up loud produces hot spots near the speakers and dead zones between them. More speakers at lower volume is always more intelligible.
Do this: Size for coverage, not for total wattage.
In a mosque or hall with hard surfaces, ordinary speakers create echo that destroys word intelligibility. Adding power makes it worse.
Do this: Column speakers with directional projection.
Every announcement goes everywhere. A fire drill on floor three interrupts a meeting on floor eight, and people start ignoring announcements.
Do this: Plan zones before cabling. Retrofitting requires new cable runs.
If the PA doubles as emergency announcement, it must override music and play evacuation audio on alarm. Retrofitting this costs more than specifying it.
Do this: Confirm fire requirements at design stage with the fire officer.
Specifications, models and pricing sit on the product pages.
Rules we apply on every installation. Share this with your installer.
Long runs and many speakers on one amplifier.
Quiet offices 3 W, shops 6 W, factory floors 10 W.
An amplifier run at 100% clips and fails early.
Let reception page one floor.
Ceiling speakers lose coverage in tall spaces. Use horns or column speakers.
A PA that goes silent in a power cut fails at the one moment it is needed.
Coverage area and ceiling height choose the speaker. Total speaker wattage then chooses the amplifier. In that order — never the reverse.
The speakers define total wattage. Picking an amplifier first means either wasting money or clipping the output.
Exceeding the amplifier rating causes clipping and eventually destroys both the amplifier and the speakers.
They are not weather rated. They will fail in the first monsoon.
If speech is unclear, the problem is coverage or reverberation. Louder makes it worse, not better.
An evacuation system that stops working during a power cut is worse than none, because people rely on it.
Tiled and concrete halls smear speech. More, quieter, closer speakers beat fewer loud ones every time.
Coverage area and ceiling height decide the speaker; total speaker wattage decides the amplifier.
Ceiling speakers on a 100 V line. Even coverage, nothing visible, easiest to add zones to later.
Every product above is one DigiMark Solution imports, stocks and warrants. Pricing is quotation-based and depends on quantity and configuration — request a quotation or ask on WhatsApp.
What to state so you get comparable quotations.
| Sector | What to specify | Typical scale | The clause bidders exploit |
|---|---|---|---|
| Mosque | Interior coverage plus exterior minarets; clear speech reproduction; simple single-operator control | Per mosque | Interior and exterior are different speaker types — specify both separately |
| Factory | Ambient noise level in dB; horn speakers for the floor; zone separation between production and offices | Per block | Give the measured ambient noise figure, or bidders will guess low and under-specify |
| School | Classroom zones; bell integration; central control from the admin office | Per building | State whether bells and announcements share the system |
| Hospital | Low-disturbance zoning; ward-level control; emergency override | Per floor | Specify which zones must be excludable from general paging |
| Shopping centre / commercial | Background music plus paging; zone control per floor or tenant | Per floor | Background music and paging have different quality requirements — state both |
| Railway / transport | High intelligibility over crowd noise; evacuation compliance; monitored lines | Per platform | Intelligibility standards, not wattage, are the specification here |
Divide your floor area by the coverage of one speaker at your mounting height. A speaker at 12ft covers roughly 220 sq ft with good clarity, so a 10,000 sq ft floor needs about 46 speakers. Higher ceilings cover more area per speaker but reduce intelligibility. Use the calculator above.
Add the wattage tap of every speaker, then add 30%. If 46 speakers are each tapped at 6W, that is 276W of load, so specify a 360W amplifier. Running an amplifier near its rated maximum causes distortion, heat and early failure — and distortion is exactly what makes announcements unintelligible.
A 100V line system lets you connect dozens of speakers on a single pair of wires over hundreds of metres, with each speaker's volume set individually by a tap setting. Conventional low-impedance wiring limits you to a handful of speakers and short runs. For any building-wide system, 100V line is the correct architecture — if a supplier quotes low-impedance for a multi-room installation, they are quoting the wrong system.
Usually one of three reasons: the amplifier is running at maximum and distorting, there are too few speakers turned up too loud creating hot spots and dead zones, or the space is reverberant and needs directional column speakers rather than ordinary ones. In a reverberant hall, adding power makes intelligibility worse rather than better.
Above roughly three distinct areas, yes. Without zones every announcement goes to the whole building — a delivery notice interrupts every meeting, and people quickly learn to ignore announcements entirely. Plan zones before cabling; retrofitting zone separation into a single loop means pulling new cable.
Yes, with a fire alarm interface that overrides music and plays evacuation audio on alarm. This is often a code requirement rather than an option. Specify it at design stage and confirm the requirement with your fire officer — retrofitting the interface costs considerably more than including it.
Prices and figures as of September 2026. Confirm with a quotation.
Free site survey across Dhaka and Chattogram. Our engineers confirm the design before anything is quoted.