ohms

It makes them different. Some things can be better - they often claim that requiring more power tightens up the bass and controls distortion better. It may also change the character overall - better would be subjective to your preferences.

Whether requiring heavier amplification for even the most casual listening is better - is another matter entirely. :)

More impedance requires more voltage, but is easier on the amp because it requires less current. Amps will perform better with high impedance loads, meaning stuff like distortion. Don't make impedance a deciding factor in buying a headphone. It's much better to choose a good headphone (of any impedance) and find a suitable amp to match.

High impedances are also less susceptible to problems with electrical damping caused by an amp's output impedance. And most of the time they're less likely to be colored by output impedance as well. Again, a suitable amp won't cause problems with any impedance.

High impedances don't need more power, if you use the scientific definition of power (watts). Sensitivity (in dB/mW) determines how much power is needed. But you get less power for every volt with high impedances. How hard a headphone is to drive depends as much or more on sensitivity than impedance.

Higher impedance headphones will give you a higher damping factor resulting in a "tighter" sound than the lower impedance ones.

This is a really dangerous discussion.  Impedance is one tiny factor in creating sound, and not the most significant by a long shot.

It also really depends on what you are using to drive said headphones.

To my understanding, high impedance headphones weren't designed to sound better, they were designed to have less impact in a studio where numerous headphones were being plugged in and out--it creates less problems in a series (or parallel or whatever).

The "tightest" sounding headphones I've ever owned have been my 25 ohm DT48 and my low impedance DR-Z6.

Get the headphones with the sound you want, then find a source that will drive them well.  Beyond that, impedance means nothing.

I suggest looking into www.innerfidelity.com and search up the DT880. There is a comparison there that might be useful.

If you plug a bunch of headphones that require a lot of current (low impedance) into an amp source, it puts a lot of pressure on the amp and can do damage to the amp.  If you have a bunch of high-voltage headphones into an amp (high impedance), they just get quiet if there's too much pressure.

Unless you're running a multi-headphone distribution system, it's something you don't have to worry about.

Quote:

Originally Posted by nikp 

Higher impedance headphones will give you a higher damping factor resulting in a "tighter" sound than the lower impedance ones.

Shouldn't really make much of a difference if your amplifier's output impedance is really close to zero. 

Sighted listening test --> bias --> Night and day difference between DT770/80 and DT770/250. 

Quote:

Originally Posted by CedricE 

You kind of confused me by saying: plugging high voltage headphones into an amp (high impedance)

...shouldn`t high voltage headphones have a low impedance?

I think they are using voltage requirement and impedence interchangably. High voltage (impedence) reduces current requirement... low voltage (impedence) increases current requirement.

Think of it like a water pipe. A smaller pipe opening (high impedence/more resistance) doesn't need as much water to fill, as a big gaping sewer pipe (low impedence/less resistance)

With just one phone - the lower impedence makes better use of the amp's juice. But if you have many phones going into a system, you run out of water, if you will, unless you use higher impedence phones (smaller pipes). 

Current is measured in amperes, so no. High impedance takes more voltage, less current, same power if the sensitivity stays the same.

I'm gonna throw some numbers at you, get ready to duck. They're equations to relate power to voltage and current.

To find power (in watts, labeled P) from voltage (in volts, labeled V) and current (in amperes (I think whole amperes), labeled I for some reason), you do this:

P = I x V

To find power from voltage and impedance (R), you do this:

P = V^2 / R

To find power from current and impedance, you do this:

P = I^2 x R

So as might be able to see, as impedance increases, voltage must increase to achieve the same amount of power, and current must decrease to achieve the same amount of power. Because it's the headphone's sensitivity that determines how loud it gets with a given amount of power and not the impedance, as impedance increases and sensitivity stays the same voltage must increase, and current must decrease.

I can throw numbers in there so it looks less alien, if you need it.

that is exactly right.. because voltage pressure can be positive or negative.

you could think of the amperes as the capacitor bank, and the voltage as the switching transistor.

but..

ohms is of zero indication as to how good or bad the headphones are.

i might say 'dont expect a very VERY low ohm speaker to be any good'

and i say this because of one real good reason, the materials used in the voice coil are going to be much more expensive to be complex AND low resistance.

and besides.. it gets to be about this clear,

to keep the voice coil in compliance with amplifiers already on the market, it is simply easier to use computers to find the perfect 'hiding spot' for the extra wire to bring the resistance up.

that extra wire is going to work like a cooler to extract away heat.

you get more power handling from the speaker, and you can use the same exact amplifier without needing to build a new one (unless your distortion can be lowered thanks to new components).

imagine if the audio industry started to release lower ohm speakers and when you plug them into your current amplifier, the speakers get loud before you reach 35% volume on the amplifier.

and if you or somebody else accidently turns the amplifier up to 50% .. you blow a speaker (or both).

not worth the embarassment of selling different amplifiers for the lower ohm.

but anyways..

be sure to keep the ohm load within the specifications of the amplifier, it is ment to keep the distortion levels from the amplifier down.

playing a lower ohm speaker puts more voltage and/or amperes through many (or most) of the pieces on the circuit board.

that is how things break.

the audio industry has been working hard to make an impact.

the newer amplifiers probably wont show any ability to 'overclock' by using lower ohm speakers than recommended.

the most of it is making a match within the simple terms and specifications given.

it is almost color-coded for you in some places.

the rest of the setup is going to come from what you do to tweak the sound.

this proves to be less and less from headphones?

it will be more and more from home theater speakers?

there is a reason to see how 'involved' you get with your audio hobby.

but the good news is..

there is actually something out there to satisfy anybody (or will be coming in the future)

still a few loose ends not being updated yet.

think of all the new high-definition audio thanks to bluray.

none of the PC soundcards support decoding it yet.

and that means there are headphones waiting to be released with those new soundcards.

hopefully some serious updates to the virtual surround sound API too.