IMPEDANCE IN HEADPHONES - WHAT YOU NEED TO KNOW

What is impedance ? (in headphones)   

• In layman terms, it is the resistance that the headphone offers. It is measured in Ohms (Ω). 
• With the increase in impedance, the power that is required to drive the circuit also increases.

 

The beyerdyamic DT 770 pro (250 ohms version). It also offers the 32Ω & 80Ω for consumer level application.

Types of impedance :

Low impedance 

• Headphones that have an impedance rating of less than 50 ohms are considered to be low impedance as they can be driven by any consumer level device like a laptop, mobile phone etc. 
•  They don't require a dedicated amp.

High impedance 

• Headphones that have an impedance rating of over 100 ohms are generally considered to be high impedance as they require a dedicated amp to obtain normal hearing volume.

Impact on loudness :

• Normally, headphones with a lower impedance rating sound loud enough whereas headphones with a higher impedance can also deliver enough volume provided it is complimented by a suitable amp.
• If the headphones are going to be connected to a laptop or a mobile phone etc. , then one can go for the lower impedance headphones as they require lower power whereas if the headphones are to be used for mixing/studio related purposes then, ideally, one can go for higher impedance headphones with an amp.

Impact on sound quality :

• As such it doesn't really affect the sound quality but a higher impedance rating does help in reducing the distortion that occurs in the background. Here's how - 
• The impedance depends on the kind of winding that the voice coil has got. A headphone with higher impedance rating will have very thin wires running around the coil which reduces the air gap and this in turn increases the strength of the electromagnetic field which finally reduces the distortion that occurs in the background as compared to headphones with a lower impedance rating.

If you want to know more about impedance and stuff, check out the links below -

1. NwAvGuy

2. CNET- low vs. high impedance 

In my upcoming posts, i'll be explaining about stuff like factors affecting headphone quality, things to keep in mind before purchasing headphone, gear reviews etc. 

So stay tuned!