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Sound Quality of Beyerdynamic DT 770 Pro 80 ohm vs. 250 ohm

post #1 of 9
Thread Starter 

Hi,

 

Assuming that both are powered by the same headphone amp (something like the FiiO E11 or Headroom Total Bithead, e.g.), are there noticeable differences in sound quality between the Beyerdynamic DT 770 80 ohm version and the 250 ohm version?  PurpleAngel (1/30/12) says the 80 ohm version is a "little more bassy", while the 250 is a "little more balanced".  (And I've seen similar claims elsehwere.)  I'm wondering if anyone can elaborate on this.

 

In his comparison of the Beyerdynamic DT 880 32 ohm and 250 ohm at Innerfidelity.com, Tyll Hertsens complains about the sound quality of the 32 ohm version, in comparison with with the 250 ohm version.  I'm wondering whether one might have similar complaints about the sound quality of the 80 ohm DT 770 in comparison with the 250 ohm DT 770.  

 

I'd like to get either the DT 770 80 or 250 ohm some time soon.  It may be relevant to note that I'll be listening to all types of music on these.  However, I'd like something with particularly good bass for listening to electronic music.  Primary sources will be ipods, iphones, and mac laptops.

 

Thanks so much!

 

Mark

post #2 of 9

If it were me I would pick up the lower impedance headphone.  The FiiO has an output impedance of .5 Ohms so even with 80 Ohm headphones you are going to have a large damping factor.  Going to 250 Ohm headphones is only going to lead to possible power issues for the driver.

 

Getting the lower impedance headphone is almost always better excluding headphones with impedances less than 30 Ohms.

 

They should sound the same, but the impedance is going to directly affect three things.

 

1.)  From Ohms Law we see that V=I*R

Voltage is equal to current times resistance ( impedance )

 

Your FiiO is going to try to give a constant voltage so as the impedance increases the less current will be drawn from the amp.  This is typically a good thing.

 

2.)  From Joule's Law we see that P = V^2 / R

The power drawn from the amp and thus fed to the drivers is equal to the voltage squared over the resistance ( impedance ).

The higher the impedance the less power is going to be drawn from the amp and delivered to the drivers.

This is one of the reasons I stay away from high impedance headphones say 600 Ohms or more.  You are going to have trouble delivering enough power to the headphone drivers.

 

3.)  The damping factor

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

This is basically how well the system can control the driver.  Having too little damping ( factor ) can lead to distortion similar to not having enough spring in your shock absorbers on your car.  You can get unwanted oscillation in the driver in the case for our headphones.

post #3 of 9

Hi Na Blur, you say "Going to 250 Ohm headphones is only going to lead to possible power issues for the driver", but then you're saying "This is one of the reasons I stay away from high impedance headphones say 600 Ohms or more" - so is the 250 still ok to drive or you still think  there could be power issues? Thanks.

post #4 of 9

Since the OP already plans to get a FiiO E11 or other comparable amplifier, there would not be power issues anyway.

post #5 of 9
Quote:
Originally Posted by AlexiusMeinong View Post
Assuming that both are powered by the same headphone amp (something like the FiiO E11 or Headroom Total Bithead, e.g.), are there noticeable differences in sound quality between the Beyerdynamic DT 770 80 ohm version and the 250 ohm version?  PurpleAngel (1/30/12) says the 80 ohm version is a "little more bassy", while the 250 is a "little more balanced".  (And I've seen similar claims elsehwere.)  I'm wondering if anyone can elaborate on this.

In his comparison of the Beyerdynamic DT 880 32 ohm and 250 ohm at Innerfidelity.com, Tyll Hertsens complains about the sound quality of the 32 ohm version, in comparison with with the 250 ohm version.  I'm wondering whether one might have similar complaints about the sound quality of the 80 ohm DT 770 in comparison with the 250 ohm DT 770.  

I'd like to get either the DT 770 80 or 250 ohm some time soon.  It may be relevant to note that I'll be listening to all types of music on these.  However, I'd like something with particularly good bass for listening to electronic music. Primary sources will be iPods, iPhones, and mac laptops.

 

Thanks so much!

 

Mark

If you wanted to save a few dollars, you can get used KRK KNS 8400 off eBay for under $100.

Not as bassy as the DT770s(but still decent bass), they are only 32-Ohm and much easier for traveling with.

post #6 of 9
The DT990 Pro walks all over the DT770 Pro for your genres, if you don't mind open ear headphones.
post #7 of 9

250 Ohms should be just fine for what you have.  It would still go with the 80 Ohm version.  The reasoning is on headphones with higher impedances there becomes a frequency dependance in the impedance.

 

Take a look at the following graphs:

http://graphs.headphone.com/graphCompare.php?graphType=7&graphID[]=2881&graphID[]=853&graphID[]=2141

 

See how the impedance curves up near the fundamental frequency of the driver ( 100Hz )?  This is a sign of a hard to control driver.  The impedance is changing as the frequency changes.  Thus the current / power needs are going to change making it harder to control.  See how the 25 Ohms D2000 is very flat.  That is going to be a much easier driver to control.

 

Part of me thinks this is a results of impedance mismatching between the headphones and the output stage of the amp.  Anyone out there tried varying the output impedance of their amp and doing the measurements?

post #8 of 9
Quote:
Originally Posted by NA Blur View Post

250 Ohms should be just fine for what you have.  It would still go with the 80 Ohm version.  The reasoning is on headphones with higher impedances there becomes a frequency dependance in the impedance.

 

Take a look at the following graphs:

http://graphs.headphone.com/graphCompare.php?graphType=7&graphID[]=2881&graphID[]=853&graphID[]=2141

 

See how the impedance curves up near the fundamental frequency of the driver ( 100Hz )?  This is a sign of a hard to control driver.  The impedance is changing as the frequency changes.  Thus the current / power needs are going to change making it harder to control.  See how the 25 Ohms D2000 is very flat.  That is going to be a much easier driver to control.

 

Part of me thinks this is a results of impedance mismatching between the headphones and the output stage of the amp.  Anyone out there tried varying the output impedance of their amp and doing the measurements?

Tyll at InnerFidelity did this while testing the DT 48 E. There was ever so slightly more distortion but nothing real major. It's worth noting that the DT 48 E has basically a flat impedance curve. 

post #9 of 9
Quote:
Originally Posted by NA Blur View Post

250 Ohms should be just fine for what you have.  It would still go with the 80 Ohm version.  The reasoning is on headphones with higher impedances there becomes a frequency dependance in the impedance.

 

It is correct that the impedance of a dynamic driver varies with frequency, but - everything else being equal - a lower impedance headphone is worse in this respect. Basically, for the least amount of frequency response variation, you want the ratio of the headphone impedance and source output impedance to be the highest possible. These two impedances form a voltage divider, which has a gain of |Zload| / |Zout + Zload| (note: Zout and Zload are complex numbers, and depend on the frequency); therefore, if Zload >> Zout, then a nearly flat response is guaranteed. A typical recommended minimum ratio is 8, but it really depends on the headphones. Otherwise, it can still be flat if both impedances are close to being purely resistive. This is the case with your D2000 example, but not with some other low impedance headphones (e.g. the HD598).

It is a common myth that impedance peaks require "more power", but an amplifier ideally behaves as a voltage source, so it actually outputs less power at the impedance peak, because the voltage is the same but the current is lower. This makes sense, as the impedance peak is at the resonance frequency of the driver, and it takes less force (=current) to move the diaphragm at a frequency the driver resonates at. The difficulty of handling the peaks comes from the fact that it requires a low output impedance, and the amplifier needs to deal with a reactive load. Again, a higher impedance headphone is easier, because it is easier to force a voltage on something that has high impedance.

Overall, the only major aspect in which a high impedance headphone is not better is the amount of voltage required for a given power. Of course, that is obviously an important one with the popularity of the iPod and other similar low voltage devices.

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