Calculation of speaker power

guzhong72

Calculation of speaker power [Copy link]

Is there anyone on the forum who can tell me how to understand the rated power and maximum power of a speaker and how to calculate it? If an oscilloscope is used to measure the input signal at both ends of the speaker, what parameters should be read to correspond? Thank you

maychang

The International Electrotechnical Commission issued the "Electroacoustic Device Loudspeaker" standard: (1) The rated noise power is defined as the continuous input of an analog noise signal (pink noise after bandpass filtering and limiting) to the speaker, and continuous operation for 100 hours without overheating or mechanical damage. The power size has nothing to do with the distortion value. (2) The rated maximum sinusoidal power is a single-frequency continuous sinusoidal signal sent into a given frequency band, and it works continuously for one hour. At this power, the vibration of the speaker voice coil should not produce a bottoming sound, and the speaker will not overheat or mechanically damage. (Other power regulations are omitted) These powers are much larger than the standard power (such as music power) that takes distortion into account, and are generally more than 5 times larger.

maychang

An oscilloscope can only see the aforementioned continuous sinusoidal signal voltage and then convert it into power. The power of a noise signal cannot be seen using an oscilloscope.

xujian2000

I benefited from it, thanks for sharing!

topwon

Generally, the maximum undistorted power is calculated by measuring the maximum peak-to-peak voltage of a 1KHz sine wave signal without waveform distortion, dividing it by 2 to get the peak value, and then multiplying it by 0.707 to get the effective value of the voltage. The power value is obtained by squaring and dividing it by the ohm value.

chunyang

The rated power and maximum power of the speaker are designed and tested. Although there is calculation in the process, it is not simply calculated. If you want to test the actual speaker's loaded power, measure the effective value of the voltage across the speaker and then calculate it based on the speaker's impedance. If you want to test the actual output power of the speaker, you need to use a special instrument to calculate it based on the sound intensity and distance.