Understanding the power of amplifiers and speakers

Are you having trouble finding your way around the technical parameters of amplifiers and loudspeakers? Watt, impedance, sensitivity, Watt RMS: let's decrypt and explain how to choose the right audio equipment for your Hi-Fi system.

The difference between power output and power handling capacity

What differentiates the operation of an amplifier from the one of a speaker in terms of power is, of course, that we speak of power output for amplifiers and power handling for speakers. The power handling capacity of a speaker is actually the amount of current that the speaker's diaphragm coil can handle without being damaged.

The link between speaker sensitivity and their power

The sensitivity of a speaker or headphone, measured in decibels, is an important factor in determining the power of your equipment. In fact, this value is a good indicator of determining if your speakers are easy to power or not. For example, speakers with a sensitivity of 92dB will be easier to power than speakers with a sensitivity of 89dB. Since sensitivity is measured on a logarithmic scale, the difference in power required to achieve the same result with 92dB and 89dB speakers is almost doubled. In other words, if you achieve a certain volume with 93dB speakers and a 100W amplifier, and want to obtain the same sound level with 89dB speakers, you'll now need an amplifier capable of delivering 200W of power.

The relationship between power and impedance

The relationship between power and impedance is an important concept. The majority of equipment advertises delivered and admissible power at 4 ohms load, but some equipment operates at 2, 6 or 8 ohms. That's why it's important to understand the relationship between advertised/admissible power in watts and the impedance load of a device. For example, if you pair a 2x 100W amplifier rated at 4 ohms with 4 ohm speakers, you'll get the most out of your equipment. On the other hand, if your 2x 100W amplifier at 4 Ohms is paired with 8 Ohm speakers (which require more power), you'll lose around half the volume output of your Hi-Fi system. It's also important to note that amplifiers are rarely used at maximum power, as this can lead to distortion.