To cut the long story short, the difference lies in levels of output power on various devices that are used for audio listening with the same headphones.
Impedance of headphones
The impedance of headphones varies from 8 to 600 Ohm. Let’s review the most common ones, with impedance of 16-64 Ohm. To compare the characteristics of volume, voltage, sensitivity, it is important to know the rates of headphones’ impedance and the level of voltage at the output of your phone. The average impedance of mobile phones is 16-32, sometimes 64 Ohm. The voltage is about 200 mV.
Sound quality and impedance
If we count the consumption of power, the headphones of 16 Ohm will take 2.5 mW, while 32 Ohm – 1.25 mW. It means that high-impedance headphones will sound quieter, but take less battery power. On the contrary, low impedance ones will sound louder and take more power from the battery.
To make the accounting simpler, let’s make a short note to remember:
- Low impedance headphones provide higher volumes for higher sensitivity. They consume much battery power but work great with low impedance devices like smartphones and players.
- High impedance headphones will sound much quieter for lower sensitivity but they take less battery power saving its life. They will require an amp with a high level of output voltage. That is a great choice for fixed audio devices.