Sensitivity & Headphones

Ever wondered how your headphone is also sensitive just like you? What actually is sensitivity? How does it affect your headphone performance?

That just sounded like a never ending array of questions. Don't worry. Let's make it simple. 

Sensitivity in general is the measure to how much pressure a person can take in a situation. right? Exactly the same with headphones. Your headphones are tuned to a range of Sound Pressure Level (SPL) to which they are sensitive. Sound sensitivity is measured in Decibels (dB). 

When the electric signal is converted to sound by the headphone driver, it intakes only a certain amount of power. This power in mW (milliWatts) is used to define the  SPL/mW when concerned with sensitivity. To make it sound a little less geekier, sensitivity is measured with sound pressure the headphone can take in one mW of power. 

The safe range for sensitivity of a headphone is 75dB to 110dB. 

Wait. Is your ear that sensitive? Yes, the Human ear can handle a maximum of 100dB for 20 minutes or 110dB  for 8 minutes. Check out this chart.

Now that we know the sensitivity of our ears and the headphones we don, the other important question that arises is how is Impedance related to sensitivity?

Impedance is the resistance of the driver to electric current. Headphones and earphones used for casual listening have impedance between 15 to 32 ohms. Headphones having higher impedance are used by professionals or audiophiles. In simple words, as impedance increases, amplification is required. Read more about impedance here.

Sensitivity and impedance go hand in hand. A fixed impedance and a fixed sensitivity range help in keeping the headphone from getting damaged from excessive electric signal. It is designed to keep a listener comfortable as he listens to music.

To sum up the case, Sensitivity of headphone is designed to keep our ears protected. Headphones cannot play music louder than what our ears can take in.