Impedance and damping coefficient

Impedance: It refers to the voltage-to-current ratio of the speaker input signal. The input impedance of the speaker is generally divided into high impedance and low impedance. Above 16Ω is high impedance. Below 8Ω is low impedance. The standard impedance of the speaker is 8Ω.

In the same power amplifier and output power, low-impedance speaker can get a larger output power, but the impedance is too low, it will result in under damping and bass degradation and so on. So although this indicator has nothing to do with the performance of the speakers, it is best not to buy low-impedance speakers. The recommended value is the standard 8Ω. The impedance of the headphones is generally high impedance - 32Ω is common. The impedance of a power amplifier can generally be labeled as an equivalent impedance, such as a 130W output at 4Ω, which is roughly equivalent to an equivalent 80W output.

Damping factor: refers to the ratio of the amplifier's rated load (speaker) impedance to the actual impedance of the power amplifier. A large damping coefficient indicates that the output impedance of the power amplifier is small, and the damping factor is the ability of the amplifier to control the speaker cone movement after the signal disappears. An amplifier with a high damping factor acts more like a short-circuit for the speaker, reducing its vibration at the end of the signal.

The output impedance of the power amplifier directly affects the low frequency Q of the speaker system, which affects the low frequency characteristics of the system. The Q value of the speaker system should not be too high, generally in the range of 0.5 to l, and the output impedance of the power amplifier is a factor that raises the low frequency Q value, so generally it is desirable that the output impedance of the power amplifier is small and the damping coefficient is large. The damping coefficient is generally between tens and hundreds, and the damping coefficient of a high-quality professional power amplifier can be as high as 200 or more.