One of the items that we often find on the gaming headphone box is: Headphone impedance or acoustic impedance . We can safely say that the acoustic impedance is one of the most important (if not the most important) specifications to be taken into consideration when buying a pair of headphones.
This is not only because it tells us a little bit about the character of the headset, but also because it tells us what we will need to make it work properly. Fortunately, it’s a fairly easy concept to explain.
What is the acoustic impedance in Headphones
Impedance is electrical resistance – in essence, it is a value that indicates the ability of something to resist the electric current that flows through it. As we have seen in our guide on drivers, the sound reaches the headphones in the form of electric current and is then transformed into sounds.
Impedance is a “measure of the resistance that a circuit has to a current when a voltage is applied”.
The unit of measurement used is the ohm (Ω) and through this value we are able to understand how much power our headphones will need to reach a reasonable listening volume.
Why is headphone impedance important?
It is important to know the impedance of our headphones because the higher the ohm value the greater the minimum power requirement to make them sound correctly.
Impedance indicates whether or not our device is capable of making headphones play properly. Some devices like smartphones may not be able to pump enough energy into the headphones.
The consequence of a lack of energy on the part of the sound source could result in too low a volume and even distortions of the sound itself may appear and this is absolutely not good.
Headphone impedance: interpretation of values
The interpretation of the impedance value is quite easy.
Impedance up to 32Ω Any portable device should be able to offer enough energy to reproduce sounds adequately. (see smartphone)
Impedance from 33Ω to 100Ω This is the intermediate band, a smartphone may be able to obtain a fairly high volume but it is not safe. A portable headphone amplifier may be required to achieve optimal volume and quality.
Impedance greater than 100Ω An amplifier is required above 100Ω. In gaming headphones you will hardly find a very high impedance, but if you decide to go on headphones for audiophiles you will find a wide range of headphones that go well beyond 100Ω.
Do you need a high acoustic impedance?
As we have seen, a high impedance value can lead us to buy an amplifier, but what are the real benefits of a high ohm value? Would it be easier to buy headphones with a low value and be sure that they work properly with any device right?
Headphones with a high acoustic impedance value , thanks to their ability to withstand greater input power, are able to reproduce the sound more accurately and with more vivid sounds.
Usually this type of headphones are more expensive and tend to be a little niche, especially in video games where the vast majority of players do not use professional headphones, but gaming headphones and therefore with poorer specifications than those for high music level.
Another value related to impedance is sensitivity , although this is usually not taken into consideration during the purchase phase of the headphones .
The headphone sensitivity is measured in decibels (dB) and this value indicates how strong play a pair of headphones to a certain power. So comparing two identical headphones but with different sensitivity for the same power input, the model with the higher sensitivity will reproduce a louder sound than the one with a lower sensitivity. This means that we will be able to play higher audio with headphones with greater sensitivity.
Essentially, sensitivity is a measure of how loud a pair of headphones will sound. A value lower than 86 dB (decibel) is considered low , while a value higher than 110 dB is considered high.
Is the sensitivity of the headphones an important value?
Although this value can be useful in choosing our next model of headphones, it is not a very reliable value, as each manufacturer measures this value differently and therefore with the same sensitivity but with different manufacturers two headphones could play at different levels.
In addition to the sensitivity value, the sound sources and the amplifiers used must be taken into consideration as both affect the power of the audio of our headphones and therefore will make the sensitivity value an increasingly inaccurate measurement meter.
So the value of impedance is much more relevant than that of sensitivity in the choice of headphones. An impedance suitable for the audio source will ensure that we can get a fairly high volume regardless of the sensitivity.
Sometimes the sensitivity is called by the manufacturers efficiency or sound pressure level, this is because when sounds are reproduced, waves are created in the air which make sounds reach us, the higher the volume the higher the sound pressure.