Speaker Sensitivity Tester
Compare how loud two speakers play at the same amplifier setting using your microphone, and work out the amplifier power a speaker needs to hit a target loudness at your seat. A built-in calculator turns a rated sensitivity (dB/W/m), target SPL and distance into the watts and headroom required.
ℹ Your microphone is not calibrated, so this tool cannot read absolute sensitivity (dB SPL at 1 W / 1 m). The mic test only gives a RELATIVE level difference in dB between two speakers measured in the same spot at the same volume — useful for matching a pair or spotting the louder one, not for a spec sheet. Turn off mic auto-gain / noise suppression (this tool requests that), keep the mic and amp untouched between A and B, and for real figures use a calibrated SPL meter at 1 m. The power calculator is exact maths from your inputs; its answer is only as good as the sensitivity number you type.
Play the same test signal at the same amp/volume setting through speaker A, capture its average level, then physically swap to speaker B (or switch your amp to it) without touching the volume or the mic, capture B, and read the relative difference. Place the mic at one fixed listening spot for both.
🔊 Safe-volume notice: the test signal plays through your speakers. Start low and raise gradually. Keep the amplifier volume identical for A and B — that is the whole point of the comparison. Loud, sustained tones can damage hearing and tweeters; protect both.
Enter a speaker’s rated sensitivity and how loud you want it at your listening seat. The tool uses the inverse-square law (−6 dB per doubling of distance) and the power relation (+3 dB per doubling of watts) to find the amplifier power required, plus the power for a comfortable headroom margin above your target.
How It Works
Speaker sensitivity (sometimes loosely called efficiency) is how loud a speaker plays for a given input, quoted as dB SPL measured at 1 metre with 1 watt of input — written “dB/W/m” or “dB @ 1W/1m”. A higher number means more loudness for the same power: a 90 dB/W/m speaker is 3 dB louder than an 87 dB/W/m one driven identically, which is the same as doubling the amplifier power. Sensitivity is set by the driver and cabinet design and is independent of the volume knob; it tells you how much amplifier you need.
Measuring the absolute figure properly requires a calibrated measurement microphone and SPL meter in a controlled space, a known 1-watt drive level (2.83 V into a nominal 8 Ω load), and the mic exactly 1 m on axis. A phone or laptop mic is not calibrated: it has its own frequency response, unknown gain, and usually automatic gain control that fights you. So this tool does not try to report an absolute sensitivity number. Instead, the mic mode does something a phone mic can do honestly: a relative comparison. With the amplifier set once and never touched, you play the same signal through speaker A and capture the average level the mic sees, then through speaker B in the same spot, and the tool reports the difference in dB. Because both speakers share the same (unknown) mic gain and room, that difference is a meaningful relative result even though neither absolute reading is calibrated.
The power calculator is exact arithmetic from your inputs. To reach a target SPL at distance d, the speaker first loses level over distance by the inverse-square law — about 20·log10(d) dB relative to its 1 m rating (about −6 dB for every doubling of distance) in a free field. The level still needed above the 1 watt rating then comes from power as 10·log10(P) dB (+3 dB per doubling of watts). Solving for power gives P = 10^((target − sensitivity + 20·log10(d)) / 10) watts at the seat, and the tool also adds your chosen peak headroom so transients do not clip. Real rooms add some bass gain from boundaries and reflections, so the true power needed is often a little less than the free-field figure — treat the result as a sensible upper estimate, not a guarantee.