Unlike the speakers and amplifiers, the impedance of the headphones can vary from to several hundred ohms 16.
As shown in a previous post on Computerannals, the impedance is directly related to power. It is the resistance of thehelmet to the passage of the signal. The higher, the longer it will provide power to the helmet so that it works correctly. We understand that a helmet suitable for listening on a device connected to the sector will not have the same requirements that a headset connected to a mobile device. The mobile device running on a limited power source-battery-it makes sense to choose a helmetmoderate impedance. In general, we recommend a maximum of 64 Ohms for mobile devices.Beyond that figure, the bandwidth will be trimmed at the ends, the available power will be reduced, your battery will be gray mine and will melt its autonomy. The its seem skimpy, as weakened (known asmitigation), the helmet “pulling too much” on the output of the player. However, for listening on a channel connected to the sector, a high impedance results in a decline in background noise and a band broad bandwidth.
Attention however, there is no real link between the quality of a helmet and its impedance. It is true that the high-end headsets often have a high impedance at high (600 Ohms for some models of studio), but this is due to the fact that they are meant either to use on the headphone input of a string, a source or an amplifier (no power available so problem), or be connected to an amplifier for audio headphones. If you hold a – good – headset for home listening, you can experience, with an adapter jack 3.5 mm/6.35 mm if necessary, plug it on your mp3 player, you will find detailed, powerful and rich in your usual listening sound turns into his cropped at the ends, weakened and more “thick”.
Another parameter to take into account is the power output of the headphone output of your player.Expressed in Milliwatts (mW), it gives the maximum power without mitigation of a headphone output. I take an excellent table of correspondence between power output and maximum recommended impedance, borrowed from a forum extension below:
-from 90 to 100 mW: 120 ohms
-from 60 to 80 mW: 80 ohm
-from 40 to 60 mW: 65 ohms
-from 20 to 30 mW: 32 ohms; 60 ohms with a slight attenuation
10-15 mW: 16 ohms; 24 ohms with a slight attenuation
To conclude, let me reassure all those figures turn off, the vast majority of public market helmets are designed to operate with most mobile devices, without compatibility issues. No need to worry, outside of some “exotic” helmets or nomadic devices to the little powerful headphone output, focus you on the sound quality, and – I know, I say this often – trust your ears .