[canoners]

Note: I'm not really good at audio, so I'm basically a newb
 
So my friend got each of these and find their sound nearly identical except that the 80 ohm has more bass kick, but the 250 ohm has a warmer sound.
What does impedance actually do? Lower the volume output?
 
Thanks Head-Fi.
 
EDIT: Sorry I forgot to say that these are DT770

 

[Guidostrunk]

The 250 OHM'S is harder to drive , theirs more resistance. The higher the Impedance the harder they are to drive. The signal has to travel a greater distance before sound is heard at 250 as opposed to 80. Cheers

 

[Riku540]

"These?" I assume you're talking Beyers? Their website gives a detailed explanation:
 
http://europe.beyerdynamic.com/service/faqs/kopfhoerer.html#fo547
 
It's not what impedance "does." It's what it "requires" of your headphones. There are slight sonic differences, but each model as a different power requirement. The higher you go in impedance the more powerful headphone amp you need.

 

[nikongod]

Impedance does... (basically) NOTHING!
 
What your friend is hearing is simply a difference between the 2 drivers, or headphones as the case may be.
 
There are dozens of 32 ohm headphones that sound nothing like each other, medium and high impedance headphones that sound pretty much identical, and everything in the middle. 
 
Listen to your friends headphones harder. You can describe them better than "warmer" and "bass kick" Try to listen through that top layer of audiophile press BS and hear what causes it. Its an eye opener, or a magazine closer. Heh.

 

[ViciousXUSMC]

Im sure somebody will give you a better answer than me but...
 
The Impedance is the term used for the electrical resistance in Ohms.
 
More resistance = Harder to amplify thus "lower volume"
 
 
Thats the easy thing to understand, the harder part is figuring out why anybody would want a higher impedance headphones then if it simply means its harder to ampify.
 
For that there are many reasons.  One is less current is drawn from the amplifier and that alone has many benefits.
 
Im sure somebody else can elaborate more, I dont personally own any high impedance equipment.

 

[Guidostrunk]

Agreed

Quote:

"These?" I assume you're talking Beyers? Their website gives a detailed explanation:
 
http://europe.beyerdynamic.com/service/faqs/kopfhoerer.html#fo547
 
It's not what impedance "does." It's what it "requires" of you headphones. There are slight sonic differences, but each model as a different power requirement. The higher you go in impedance the more powerful headphone amp you need.

 

[canoners]

Well, what do you guys mean by harder to drive? Their volume are pretty similar, or maybe it's just my untrained ear :|
 
I forgot to say that they're DT770

 

[Riku540]

The thing about amplification isn't just volume. It's about signal. Everything has some form of "amp" like the headphone jack of an iPod. Now think about how small the iPod is, and how big the amp for the headphone jack could possibly be. Do you think that will produce sufficient power for high performance headphones?
 
My favorite analogy to use is headphones = car. Low impedance headphones are very efficient, like hybrid fuel cars. High would be like a sports car. Both use gas, but require different grades. You wouldn't pump regular gas into a nice sports car would you?

 

[Uncle Erik]

Low impedance does not mean something is easy to drive.

An extreme example is the Apogee Scintilla ribbon speaker. It has an impedance around 1 Ohm. Yet it is a hideously difficult speaker to drive. It will overheat and literally melt amps not up to the task.

Impedance has a lot more to do with the efficiency of power transfer from the amp to the driver. Keep in mind that amps have an output impedance, as well. Those figures have nothing to do with the efficiency (measured in Decibels, or dB) of the driver or the output power of the amp, measured in Watts ("W") or milliWatts ("mW"). As with the Scintillas, something with a low impedance can be incredibly difficult to drive.

 

[Riku540]

Well, I tried to keep it simple for the OP's sake, and in direct relevance to the DT 770. You are correct, there are always exceptions. I know AKG's are not efficient at all despite their reasonably low impedance and probably require the same amount of drive as an average 250/300 ohm headphone.

 

[wuwhere]

Had a pair of those insane Scintillas, they actually dip below 1 Ohm at certain frequencies, almost a short. They were also very inefficient.
 
Just follow Ohm's law.
 

 

[canoners]

So you guys mean that a high impedance does not always equal to low volume?

 

[Riku540]

High impedance means it's harder to get louder, needing more amplification to do so. The quality of the sound is smoother, but at the cost of volume.
 
In the case of the 770 Pro's though (which are completely different from the 770 consumer) the 80 ohm is known to have far more bass than the 250.
 
Honestly, ignore these headphones unless you plan on purchasing a headphone amp as Beyers in general are not efficient at all regardless of ohm rating. You will not get their full performance nor will you being experiencing what they are really capable of. These headphones need an amp to do them justice.

 

[wuwhere]

You can't equate volume with impedance. Some amps are better at driving higher impedance hps and some are better at driving low impedance hps.
Some amps can drive both adequately.

 

[Riku540]

http://www.head-fi.org/forum/thread/513393/information-sonic-differences-between-dt770-dt990#post_6938759
 
^ Another very good read if you want detailed comparisons. Again, volume is only a factor and not the reason.