What is the difference in sound quality between high and low impedance 'headphones'?

Question

I want to record and mix music and I have been looking at some equipment, one of which is the DT 770 PRO headphones. However, this headphone is available in varying levels of impedance, namely 32 ohms, 80 ohms and 250 ohms. I could not find the answer to the question on whether high impedance equals to better quality of sound. The only answer I came across after hours of researching is, how with low impedance can be connected to virtually anything while high impedance requires an audio interface.

What are the differences between low and high impedance headphones in terms of quality of sound? Why should you choose one over the other? (Other than the fact that one requires a dedicated audio interface and the other does not).

I feel incredibly lost and an answer shedding light on this matter would be most sincerely appreciated, looking forward.

Answer 1

I don’t think there is any difference in sound quality, or at least if there is, it’s so minimal that it’s overshadowed by all the other design elements of the headphones.

The reason why different impedances are available is to work better with different devices. If you buy the highest impedance set and plug it into your smart phone, you may find that even with the volume all the way up on your phone, it’s still not very loud.

Conversely, if you buy the lowest impedance set and plug it into a professional mixing console, you might find you have to have the headphone level pot turned almost all the way down to keep it from being too loud.

In a way, that last example does relate to a sound quality difference, but not because of the headphones themselves. A stereo analog pot (knob) works best in the middle of its range. If you turn a pot almost all the way down, the stereo balance might be off a little bit and the quality of the signal through that pot might suffer. Obviously higher quality pots are more stable throughout their range, but there are inherent limitations in all gear, and the lowest level settings can often bring them out.

So that’s the one interaction between headphone impedance and final sound quality that I can think of. If you’d like to invest in one set of headphones to use for both consumer devices like phones and professional devices like audio interfaces and mixing consoles, then get the middle impedance level. Either way it might help to buy from a good retailer with a reasonable return policy so you can send back a set that seems to be too loud or too quiet for a different impedance.

Answer 2

If the source runs on a 3v power rail (a couple of AA batteries) or a 5v one (USB) you'll need low impedance cans in order to get any volume. With 12v, 24v or more to play with, higher impedance is appropriate. Neither is good or bad as such. Pick the ones that suit your equipment.

It may be that high impedance cans are perceived as inferior by analogy with high impedance microphones. In this sphere, high impedance models are typically wired unbalanced and are associated with cheaper systems. Low impedance ones are wired balanced and are 'professional'.