Amplifier power
Speaker Sensitivity Chart
Quick answer
Every 3 dB of loudspeaker sensitivity halves the amplifier power needed, so a 99 dB cabinet needs one eighth the power of a 90 dB cabinet at the same level and distance. At a 60 foot throw to 88 dBA, a 96 dB box needs 840 watts and a 102 dB box needs 211.
Sensitivity is the level a loudspeaker produces from one watt of input measured at one metre, written as something like 96 dB at 1W/1m. It is printed on every specification sheet, it is the single most consequential number on that sheet, and almost nobody compares it. A church that chooses a cabinet 6 dB more sensitive has quartered its amplifier requirement before spending anything on amplification.
The relationship is logarithmic and unforgiving in both directions. Three decibels of sensitivity is worth a doubling of amplifier power. Nine decibels, which is the realistic span between a compact budget cabinet and a horn-loaded installed box, is worth a factor of eight. Work your own room with the amplifier power calculator.
On this page
How many watts does each sensitivity need?
Watts per loudspeaker required to reach an 88 dBA average with 12 dB of peak headroom, which is a blended service, at each throw distance. Find your throw across the top and your cabinet sensitivity down the side.
At a 60 foot throw, reaching 88 dBA with headroom takes 2,110 watts with a 92 dB loudspeaker and only 211 watts with a 102 dB one, a tenfold difference from the specification sheet alone.
| Sensitivity | 40 ft | 50 ft | 60 ft | 70 ft | 80 ft | 100 ft | 120 ft |
|---|---|---|---|---|---|---|---|
| 92 dB | 938 W | 1,465 W | 2,110 W | 2,872 W | 3,752 W | 5,862 W | 8,441 W |
| 94 dB | 592 W | 925 W | 1,332 W | 1,812 W | 2,367 W | 3,699 W | 5,326 W |
| 96 dB | 373 W | 583 W | 840 W | 1,144 W | 1,494 W | 2,334 W | 3,360 W |
| 98 dB | 236 W | 368 W | 530 W | 722 W | 942 W | 1,472 W | 2,120 W |
| 100 dB | 149 W | 232 W | 334 W | 455 W | 595 W | 929 W | 1,338 W |
| 102 dB | 94 W | 147 W | 211 W | 287 W | 375 W | 586 W | 844 W |
Computed for a target of 88 dBA at the furthest seat with 12 dB of peak headroom, which is the blended service figure used throughout this site. For a speech target of 75 dBA with 10 dB headroom, divide these figures by about 40. For contemporary worship at 95 dBA, multiply by about five.
What sensitivity to expect from each type of cabinet
Sensitivity is a consequence of design, principally of how much horn loading the cabinet uses and how large the drivers are. Small, wide and cheap trends low; large, horn-loaded and narrow trends high.
A typical powered 12 inch church cabinet sits at 95 to 98 dB at 1W/1m, while a compact ceiling speaker is nearer 86 to 90 dB and a horn-loaded installed box reaches 100 to 105 dB.
| Loudspeaker type | Typical sensitivity | Why it lands there | Power for 88 dBA at 60 ft |
|---|---|---|---|
| 4 inch ceiling speaker | 84 to 88 dB | Tiny driver, no horn loading, wide dispersion | Not applicable, never used at this throw |
| 6.5 inch ceiling speaker | 87 to 91 dB | Larger cone, still no horn, coaxial tweeter | Not applicable, never used at this throw |
| 8 inch compact powered box | 90 to 94 dB | Small format, wide pattern, cost engineered | 1,332 to 3,344 W |
| 10 inch powered box | 93 to 96 dB | Mid format with a modest horn | 840 to 1,674 W |
| 12 inch powered box | 95 to 98 dB | The church default. Real horn loading on the high frequency | 530 to 1,057 W |
| 15 inch powered box | 96 to 99 dB | Larger cone, more efficient in the low mids | 421 to 840 W |
| Installed passive 12 inch | 96 to 100 dB | No amplifier packaging constraint, larger magnet structures | 334 to 840 W |
| Horn-loaded installed box | 100 to 105 dB | Full horn loading concentrates output into a defined pattern | 106 to 334 W |
| Column array | 92 to 97 dB | Many small drivers, controlled vertical pattern | 667 to 2,110 W |
| Line array element | 96 to 103 dB | High efficiency plus array gain from multiple boxes | 168 to 840 W |
| Stage monitor wedge | 95 to 99 dB | Efficiency matters because it is close to the listener | Not applicable, near field use |
| Subwoofer | 95 to 102 dB | Large radiating area, but measured in its own passband | Not comparable, different bandwidth |
Ranges are the span across current models of each type from published specifications. Always use the exact figure for the cabinet you intend to buy rather than the class average, because the span within a class is wider than the gap between classes.
The sensitivity arithmetic in one table
This is the relationship that makes sensitivity worth more than almost any other purchasing decision. Each 3 dB step halves or doubles the amplifier requirement.
A loudspeaker 9 dB less sensitive than another needs eight times the amplifier power to produce the same level at the same distance.
| Sensitivity difference | Power multiplier | Example | What that costs |
|---|---|---|---|
| -9 dB | 8.0 times | 87 dB against 96 dB | A 500 watt requirement becomes 4,000 watts |
| -6 dB | 4.0 times | 90 dB against 96 dB | A 500 watt requirement becomes 2,000 watts |
| -3 dB | 2.0 times | 93 dB against 96 dB | A 500 watt requirement becomes 1,000 watts |
| 0 dB | 1.0 times | 96 dB, the reference | The baseline figure |
| +3 dB | 0.50 times | 99 dB against 96 dB | A 500 watt requirement becomes 250 watts |
| +6 dB | 0.25 times | 102 dB against 96 dB | A 500 watt requirement becomes 125 watts |
| +9 dB | 0.125 times | 105 dB against 96 dB | A 500 watt requirement becomes 63 watts |
This is why the cheapest way to buy loudness is to buy sensitivity, and why a church comparing two cabinets on price alone can easily choose the one that costs four times as much to amplify.
How to compare sensitivity figures honestly
Check the measurement conditions. The honest figure is dB SPL at one watt at one metre, averaged across the cabinet’s usable passband. Some manufacturers quote 2.83 volts at one metre instead, which is identical to one watt into 8 ohms but is 3 dB flattering on a 4 ohm cabinet. If a specification says 2.83V and the impedance is 4 ohms, subtract 3 dB before comparing.
Check the bandwidth. A figure averaged from 100 Hz to 10 kHz is meaningful. A figure taken at the single most efficient frequency, usually right in the horn’s passband around 2 kHz, can be 4 or 5 dB higher and is not comparable to anything.
Do not compare a powered box to a passive box on sensitivity alone. A powered cabinet’s useful specification is its maximum SPL, because the amplifier is already chosen and matched. Sensitivity matters when you are buying the amplifier separately.
Remember that high sensitivity usually means a narrower pattern. Horn loading buys efficiency by concentrating output into a defined wedge. That is exactly what a deep room wants and exactly what a wide shallow room does not. Read the sensitivity figure and the coverage pattern together, never separately.
Where this chart does not apply
Maximum SPL, not sensitivity, limits a system. A sensitive cabinet that runs out of excursion at 118 dB is not more capable than a less sensitive one that reaches 128 dB, it simply gets there on fewer watts. For a contemporary service, compare maximum SPL figures as well.
Sensitivity is measured on axis. A listener 40 degrees off axis receives several decibels less, and considerably less high frequency. The tabulated power assumes the listener is within the coverage pattern.
It ignores power compression. A driver heats up under sustained power and loses sensitivity as it does, commonly 2 to 4 dB at high continuous levels. A system running at its limit for a forty minute worship set is quietly less sensitive at the end than at the start, which is another argument for headroom.
The room adds level that this does not count. Reverberant energy raises the measured level at a distant seat above the free field figure, sometimes substantially. That extra level carries no clarity, so it should never be used to justify a smaller amplifier.
Subwoofer sensitivity is not comparable. It is measured over a different passband, and low frequency output in a room is dominated by room modes and boundary loading rather than by the specification.
Sources
- Manufacturer published sensitivity, maximum SPL and coverage figures for installed and portable loudspeakers
- Amplifier power formula as implemented in this site’s amplifier power calculator
Frequently asked questions
What does 96 dB at 1W/1m mean?
The loudspeaker produces 96 decibels of sound pressure when fed one watt, measured one metre directly in front of it. It is a measure of efficiency: how much sound you get per watt of electricity. Higher is better in the sense that it needs less amplifier, though it usually comes with a narrower coverage pattern, so the two specifications have to be read together.
How much difference does 3 dB of sensitivity make?
It halves or doubles the amplifier power required. A 99 dB cabinet reaching a given level on 250 watts needs 500 watts if it were 96 dB and 1,000 watts at 93 dB. Since amplifier cost, weight, heat and circuit load all scale with power, 3 dB on a specification sheet is worth real money across the life of the system.
Is a more sensitive speaker always better for a church?
Not always. High sensitivity normally comes from horn loading, which concentrates output into a narrower pattern. That is ideal in a deep narrow sanctuary and wrong in a wide shallow one, where a narrow box leaves the outside seats uncovered. Choose the coverage pattern the room needs first, then take the most sensitive cabinet available in that pattern.
Why do some spec sheets say 2.83V instead of 1W?
Because 2.83 volts into 8 ohms is exactly one watt, so for an 8 ohm cabinet the two are identical. Into a 4 ohm cabinet, however, 2.83 volts is two watts, which flatters the figure by 3 dB. If a data sheet quotes 2.83V on a 4 ohm loudspeaker, subtract 3 dB before comparing it to an 8 ohm cabinet quoted at one watt.
Does sensitivity matter if I buy powered speakers?
Less, because the amplifier is already selected and matched to the drivers in the factory. For a powered cabinet the useful comparison is maximum continuous and peak SPL, which tells you how loud it gets in total. Sensitivity becomes the critical number when you are specifying separate amplifiers for passive loudspeakers.
Can I compare subwoofer sensitivity to main speaker sensitivity?
No. The two are measured over completely different frequency bands, and a subwoofer output in a real room is dominated by room modes and by how close it sits to walls and corners. Compare subwoofers only against other subwoofers, and expect placement to matter more than the specification does.
Researched, not professional advice. This page is compiled from published manufacturer specifications, operator manuals, FCC rules, published standards and owner-review consensus, not hands-on testing. Sound system design, rigging loudspeakers overhead, and any electrical work are jobs for a qualified professional: have flown loudspeakers and their attachment points signed off by a structural engineer or a certified rigger, and have all wiring done by a licensed electrician to your local code. Wireless microphone rules change, so confirm the current FCC position before buying. As an Amazon Associate we earn from qualifying purchases.