Nowadays, many people and many occasions talk about whether the headphones are easy to push. It is often to look at the impedance of the headphones. The lower the impedance, the easier it is to push.
This view is not wrong, but it is also one-sided, it is easy to misunderstand. Because it is only one of the factors that determine whether the headphones are good or not.
In fact, the sensitivity index of the earphone is the key factor that affects whether the earphone is easy to push. Unfortunately, many non-professionals still misunderstand the newly-introduced enthusiasts in various occasions.
What is the best state of the headset?
The best state of the headset should be higher impedance and higher sensitivity. The higher the impedance, the less current is drawn from the source (such as the Walkman), which not only saves the battery consumption of the source, but also helps to reduce distortion. At the same time, the higher sensitivity compensates for the loss of volume due to high impedance.
Some players now have a matching impedance of 16 ohms. Some users believe that the manufacturer's label (who can trust the user) only chooses 16 ohm headphones, which limits the range of headphones that users choose. In fact, it is completely unnecessary. As long as the sensitivity of the earphone is high, the impedance can be higher, which is not only harmless but also beneficial.
In general, there are two factors that affect whether the headphones are easy to drive. The first is sensitivity and the second is impedance. Even if the impedance is low and the sensitivity is not high, it is equally difficult to drive. For example, Beyerdynamic DT331, the impedance is only 40 ohms, but the sensitivity is only 86 decibels, it is really unable to push. The SHURE E5C has a sensitivity of up to 122 decibels, and although the impedance is 110 ohms, it is still very good. Tell everyone a basic common sense. Generally, when the headphone sensitivity is 3 dB, the power boosted is doubled.
Sensitivity is the primary factor in determining whether a headset is easy to drive. Impedance is a secondary factor. To determine if the headset is easy to drive, look at the sensitivity first, and the second reference impedance. In addition, portable headphones, earplugs, etc., do not have to worry about how much impedance it is - originally designed for the Walkman, how can the Walkman push it? How could it be high resistance? How can I add an amp? [The reason why the headphones have noise]
The so-called belt does not have to move, as long as it is a constant voltage output type amplifier, the impedance of the driven load is not too small, and exceeds the amplifier's maximum output current capability, then there is no problem, that is, in fact The higher the impedance of the load, the lower the current output requirement of the amplifier. The amplifier generally works more easily. Of course, if we want to get the proper output power, the impedance of the load should not be too large, otherwise the useful power will not be available. By the way, under a certain output power, the earphone should be able to emit the sound pressure that the human ear can hear, and it is also related to the sensitivity of the earphone. Generally speaking, it is expressed in dB/mw, which is the power input to the earphone by 1mw, how many dB can be generated. Sound pressure, the intensity of listening to music in the human ear is generally about 100dB, so if the output power of the earphone can reach 10mw, the sensitivity of the earphone is 95dB (common value of the headset), then the obtained sound pressure level can be Up to 105dB, almost the right fit, and 10mw output power for the Walkman, if the headset is 100 ohms, then the required output voltage is 1.4Vrms peak-to-peak, for the final stage power amplifier, the requirements are not too high, it is acceptable, as long as the power supply voltage is around 3V, which is no problem for the common DISCMAN, if the sensitivity of the headphones is too Low, can not produce enough sound pressure level, it can't be.