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Impedance and sound quality

post #1 of 4
Thread Starter 

Hi guys,

i'm going to ask another question here, but this time is little different.

Why sometimes impedance is so different between headphone models and the sound is almost the same?

And how the impedance affect the sound quality?

 

Let me put some example here:

 

Koss Pro 4AAT ---> 250 ohm

Koss Pro Dj100 ---> 55 ohm

Akg K142Hd ---->55 ohm

Grado Sr80i (wich are supposed to be the best here) ----> 32ohms

 

I know that is not like this usually but if we look at this 4 headphones it seems that the headphones with the lowest impedance are the best ones.

 

Crappy

post #2 of 4

Impedance does three things for a headphone that I will mention.

 

1.)  It is responsible for how much power the headphones draws from the source

 

2.)  It damps the oscillation of the driver ( see electrical damping )

 

3.)  It controls the phase of the signal

 

Case 1:

The higher the impedance the easier it is for a system to provide current to the headphones.

http://en.wikipedia.org/wiki/Headphones#Impedance

 

Case 2:

If the output impedance of the source is relatively high compared to the driven headphone the damping factor becomes quite low.  This in turn may lead to undesired oscillations of the driver and thus noise / distortion.

http://en.wikipedia.org/wiki/Damping_factor

 

Case 3:

http://en.wikipedia.org/wiki/Electrical_impedance

 

So in many cases a headphones with 600 Ohms may sound very similar to its 60 Ohm version especially if a sources output impedance is low.

 

There are two numbers to remember with headphones.

 

1.)  Sensitivity:  How easy it is to drive the headphones.  The higher the sensitivity the easier it is to make it the driver move.

 

2.)  Impedance:  How much current ( power ) the drivers and voice coils are going to draw from a source.  If the source cannot keep up then a lower impedance headphone is better.  If a source can handle it and damping is considered a higher impedance source is better because the damping factor goes up.

post #3 of 4

Impedance has quite nothing to do with sound quality, if your headphone output is good.

 

People here never look at impedance, when they choose their headphones, unless they are buying portable headphones, or are not planning to get an amp.

 

This is, because lower impedance headphones (below 100ohm) are usually easier to drive with portable devices.

 

But, if you have an amp with low output impedance (below 1ohm) and high enough output power it doesn't matter what the headphone impedance is.

 

 

In case my post didn't make any sense, this thread should answer your questions pretty well:

http://www.head-fi.org/t/571384/low-impedance-vs-high-impedance-huge-difference

 

 

edit: NA Blur was faster :) Ignore my post,


Edited by Headzone - 12/7/12 at 2:13pm
post #4 of 4
Thread Starter 

Thank you so much guys!!!!!!
 

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