[DrJon]

Edit:  D'oh!  Typo in the title but I can't seem to edit it.  It should be "How important is distortion *in* choosing headphones?"
 
 
Hi Folks,
 
I'm getting close to buying my first set of "real" headphones.  I'm coming from the speaker world where I've dabbled in designing speakers.  If I were to give the top priorities in designing an excellent speaker I might say, roughly, in this order:
1. flat frequency response
2. low distortion drivers
3. good phase matchup between drivers
4. flat impedance plot
 
Get all these things right and you will have a speaker that really sings. Most headphones seem to only have a single driver (is that correct?) and the impedance plots are relatively flat.  So forget points 3 and 4.  That leaves us with only the flat frequency response and low distortion to worry about.  If the frequency response isn't close to flat, things will sound funny.
 
For distortion, I've been looking at all the excellent data provided at headphone.com.  Let's compare some popular choices... the Apple stock ear buds show tons of distortion.  The Grado SR60i's are much better, but still notable distortion above 500 Hz.  The AKG K701 is lower still in distortion.  Looking around at all the full sized cans below about $500, one of the low distortion champs seems to be the Beyerdynamic DT770 32 ohm. 
 
The DT770-32's are well liked, but as far as I can tell, not nearly as much as other cans with more distortion.  Interesting.  I realize that some people enjoy even order distortion (e.g., tube amps) and odd order distortion can be jarring.
 
 

 
 
Factoring in flat frequency response, low distortion, my best guess at comfort, price, and general opinions here at head-fi, I'm leaning toward the standard 250 ohm version of the Beyerdynamic DT880's.  So let's look at the distortion of the various DT880 options.  Near as I can tell, people here seem to prefer the 600 ohm flavor over the 250 ohm, and then the 32 ohm least.  Look at the distortion plots.  The 600 ohm looks worst, by a fair margin.  Worse than the much cheaper Grado SR60's.  The 32 ohm might have the least distortion but it's a close call with the 250 ohms. 
 
 

 
 
For speakers. distortion 35 db down from the fundamental can still be heard, I find.  It's not a huge deal but it'll sound better if you can eliminate it.  I'm wondering how far down headphone distortion doesn't matter anymore.  Will the Grado noise at -90 db matter or you'll never know it's there?
 
Just trying to start an discussion that might be interesting and help me pick which headphone to get.  Thanks!
 

 

[wind016]

I think these graphs from Innerfidelity are better. http://www.innerfidelity.com/headphone-data-sheet-downloads
 
To give a comparison, distortion on Grados and Monster headphones are extremely apparent to me, but Grados tend to blur it in with their extremely bright sound signature making it sound "raw."
 
http://www.innerfidelity.com/images/GradoRS1.pdf
http://www.innerfidelity.com/images/GradoSR325i.pdf
http://www.innerfidelity.com/images/MonsterBeatsPro.pdf
 
While these headphones sounded much clearer to me,
 
http://www.innerfidelity.com/images/BeyerdynamicDT880250ohm.pdf
http://www.innerfidelity.com/images/SennheiserHD598.pdf
http://www.innerfidelity.com/images/AudezeLCD2.pdf
http://www.innerfidelity.com/images/SennheiserHD800.pdf

 

[BotByte]

Don't worry if the headphones are at least good quality.
 
I worry about distortion within my system, not from the headphones.

 

[DrJon]

Hi wind016,
 
Thanks for the info.  It's very interesting and I didn't know about that site.  The innerfidelity distortion plots looks like the 600 version of the DT880 has slightly lower distortion.  With the 32 and 250 ohm versions roughly the same.  Although 600, 250, and 32 are close to each other.  And such plots are open to interpretation (e.g., high versus low frequency distortion will not sound the same, etc.).  These data do not seem to agree with those that I posted above.  Hmmm...
 
 
Hi BotByte,
 
Yeah, you want to avoid distortion everywhere in the chain.  My experience is that watts are relatively cheap these days.  So I'm starting to address distortion at the headphone/speaker end of the chain and then working back.

 

[BotByte]

Quote:

Hi wind016,
 
Thanks for the info.  It's very interesting and I didn't know about that site.  The innerfidelity distortion plots looks like the 600 version of the DT880 has slightly lower distortion.  With the 32 and 250 ohm versions roughly the same.  Although 600, 250, and 32 are close to each other.  And such plots are open to interpretation (e.g., high versus low frequency distortion will not sound the same, etc.).  These data do not seem to agree with those that I posted above.  Hmmm...
 
 
Hi BotByte,
 
Yeah, you want to avoid distortion everywhere in the chain.  My experience is that watts are relatively cheap these days.  So I'm starting to address distortion at the headphone/speaker end of the chain and then working back.

Good cables and a good system helps.
 
Go to Monoprice for their premium cables and just buy some good components for your system. No Chinese amps or so what.
 
But you shouldn't worry too much if you're not running a turntable. That's when you spend $2000+ to make sure there isn't any problems
 

 

[DrJon]

 
I've been thinking (look out!) about these measurements a little bit more.
 
Measuring distortion is tricky because there are several ways to do it and several ways to interpret the data.  The headroom/headphone.com measurements seem to be using different frequencies for the fundamental- maybe ~380 Hz for the 250 ohm DT 880 and ~410 Hz for the others.  Not 100% comparable.  But I see that they have 2 measurements for the 250 ohm version.  One is "DT880" and the other is "DT 880" (note the space).  I posted the "DT880" but the "DT 880" has the same fundamental as the 32 and 600 ohm versions.  Anyways, this approach to distortion plays one tone and looks at the result.  Here, the 600 ohm version looks pretty bad compared to the others.
 
Looking at the innerfidelity data, I would consider it to be a little more complete representation of what we will actually hear.  If I'm reading it correctly, many frequencies are used and the resulting distortion is examined.  Plus there are 4 measurements- left and right, 90 and 100 db.  Not to mention the impulse and square wave data.  From these plots...
 
The 250 and 600 ohm versions look to be very similar.  I would say that the 600 ohm has a little less distortion and the impulse response also looks a little better with the 600 versus 250.  But they are both close and this may be splitting hairs.
 
From the headphone.com measurements, I eliminated the 600 ohm DT800 from contention due to the high distortion.  But now I'm thinking that I should consider it.  So I've got it down to the 250 versus 600 ohm DT880's.  Hmmm.  The 600 ohm may be a teeny bit cleaner.  But the 250 ohm will better allow me to play straight out from my iMac without an amp.  I'd like to run that way for a while to see if I'm really going to get into this headphone thing or not.  If not, save the cash on the amp.  If I do get into it, an amp will be in the future.
 
Which headphones to start with?  Decisions, decisions.

 

[Uncle Erik]

First, I fixed the thread title for you.  
 
Second, yes most headphones are singledrivers, notable exceptions being the AKG K-340 and various multidriver IEMs.
 
Also, pay attention to the output impedance curves of headphone amplifiers.  There are lots of OTLs, SETs, and other circuits rarely found in the speaker world.  Output impedance varies a lot and can really make headphones sound different from amp to amp.

 

[BotByte]

Quote:

 
I've been thinking (look out!) about these measurements a little bit more.
 
Measuring distortion is tricky because there are several ways to do it and several ways to interpret the data.  The headroom/headphone.com measurements seem to be using different frequencies for the fundamental- maybe ~380 Hz for the 250 ohm DT 880 and ~410 Hz for the others.  Not 100% comparable.  But I see that they have 2 measurements for the 250 ohm version.  One is "DT880" and the other is "DT 880" (note the space).  I posted the "DT880" but the "DT 880" has the same fundamental as the 32 and 600 ohm versions.  Anyways, this approach to distortion plays one tone and looks at the result.  Here, the 600 ohm version looks pretty bad compared to the others.
 
Looking at the innerfidelity data, I would consider it to be a little more complete representation of what we will actually hear.  If I'm reading it correctly, many frequencies are used and the resulting distortion is examined.  Plus there are 4 measurements- left and right, 90 and 100 db.  Not to mention the impulse and square wave data.  From these plots...
 
The 250 and 600 ohm versions look to be very similar.  I would say that the 600 ohm has a little less distortion and the impulse response also looks a little better with the 600 versus 250.  But they are both close and this may be splitting hairs.
 
From the headphone.com measurements, I eliminated the 600 ohm DT800 from contention due to the high distortion.  But now I'm thinking that I should consider it.  So I've got it down to the 250 versus 600 ohm DT880's.  Hmmm.  The 600 ohm may be a teeny bit cleaner.  But the 250 ohm will better allow me to play straight out from my iMac without an amp.  I'd like to run that way for a while to see if I'm really going to get into this headphone thing or not.  If not, save the cash on the amp.  If I do get into it, an amp will be in the future.
 
Which headphones to start with?  Decisions, decisions.

You're thinking too far into it
 
the different versions are made for different systems.
 
If you have a small system, maybe a amp/dac hooked to a laptop or so what. The 32ohm would be fine
 
If you have a good system, headphone amp + DAC or a nice home HiFi set up with some decent headphone power. The 250ohm would be nice
 
If you have a entire recording studio with specialized equipement. The 600ohm would be the job. If you tried the 32ohm here, something might backfire.
 
 
You don't aim for the highest number
 
Now amps is what causes all this. If you have a low powered amp (not a bad thing, some IEM's need them) the 32ohm would be fine.
If you have a normal amp that pushes up or past the 250ohm mark, the 250ohm
If you have a monster system that pushes power out, the 600ohm.
 
The difference is, is that each amp causes different distortion. Add the 32ohm to the 600ohm amp, that causes distortion. Add the 600ohm to the 32ohm amp, that causes distortion.
 
 
 
If you don't already have a system, go for the 32ohm version. Don't buy a amp for a headphone. Buy a headphone for your amp. You understand?

 

[DrJon]

Quote:

First, I fixed the thread title for you.  
 
Second, yes most headphones are singledrivers, notable exceptions being the AKG K-340 and various multidriver IEMs.
 
Also, pay attention to the output impedance curves of headphone amplifiers.  There are lots of OTLs, SETs, and other circuits rarely found in the speaker world.  Output impedance varies a lot and can really make headphones sound different from amp to amp.

 
Hi Uncle Erik,
 
Very kind of you to fix my stoopid typo.  

 
Yeah, I found impedance curves to matter in speaker design.  Some headphones seem to look pretty flat- a good thing. But others not so much.  I'm factoring it in as I learn about this related, but different world.
 
 

 

[DrJon]

Quote:

You're thinking too far into it
 
the different versions are made for different systems.
 
If you have a small system, maybe a amp/dac hooked to a laptop or so what. The 32ohm would be fine
 
If you have a good system, headphone amp + DAC or a nice home HiFi set up with some decent headphone power. The 250ohm would be nice
 
If you have a entire recording studio with specialized equipement. The 600ohm would be the job. If you tried the 32ohm here, something might backfire.
 
 
You don't aim for the highest number
 
Now amps is what causes all this. If you have a low powered amp (not a bad thing, some IEM's need them) the 32ohm would be fine.
If you have a normal amp that pushes up or past the 250ohm mark, the 250ohm
If you have a monster system that pushes power out, the 600ohm.
 
The difference is, is that each amp causes different distortion. Add the 32ohm to the 600ohm amp, that causes distortion. Add the 600ohm to the 32ohm amp, that causes distortion.
 
 
 
If you don't already have a system, go for the 32ohm version. Don't buy a amp for a headphone. Buy a headphone for your amp. You understand?

Are you accusing me of thinking too much?  That's a first for me.  

 
What you say makes sense.  I see how you pick the headphone according to the needs.
 
I guess that I'm at the point of not knowing how far I'm going to get into this headphone thing.  Could be far.  Or not.  I got crazy into the speaker thing, so far so that I make them myself.  So I'm thinking of getting the headphone that seems to best suit my tastes and price.  If I end up using it a lot, I'd then get an amp.  If not, well, it was a fun toy to try.  Still thinking before buying anything...

 

[BotByte]

Quote:

Are you accusing me of thinking too much?  That's a first for me.  

 
What you say makes sense.  I see how you pick the headphone according to the needs.
 
I guess that I'm at the point of not knowing how far I'm going to get into this headphone thing.  Could be far.  Or not.  I got crazy into the speaker thing, so far so that I make them myself.  So I'm thinking of getting the headphone that seems to best suit my tastes and price.  If I end up using it a lot, I'd then get an amp.  If not, well, it was a fun toy to try.  Still thinking before buying anything...

Well just remember, it's best to start out without a amp and a headphone that doesn't need one, then get a amp and a headphone that needs one.
 

 

[Argo Duck]

This is a potentially interesting thread in general, not just in terms of the OP's first buying decision: what differences matter and don't matter between headphones and speakers; how does distortion affect sound with headphones; etc. For example, 
wind016's observation concerning the interaction of distortion and sound signature (Grado/Monster) is very interesting.
 
 

 

[CRIOLLAZO]

I agree with BotByte: start with low Imp headphones straight from your MP3 Player for example and later buy mid or high Imp ones for using a headphone Amp. Reviews are subjected to music tastes and quality of the sources. A simple solution is borrow from someone else one of each one and use them with the same sources before spend your money.

 

[stv014]

Quote:

I worry about distortion within my system, not from the headphones.

Any DAC and amplifier that is worth something and is operated within its limits has a fraction of the distortion of even the best headphones. To get consistently around/within 0.1% distortion throughout the audio spectrum and at different volume levels, you basically need a LCD-2/Stax level headphone (according to innerfidelity.com graphs, at least), while the DAC of a < $100 sound card is capable of less than 0.001% at any audible frequency, and an expensive amplifier is not needed either to achieve 0.01-0.02% 20Hz to 20 kHz (better at 1 kHz). On the other hand, for a dynamic headphone, less than 1% at loud bass already counts as very good.
 

 

[stv014]

Quote:

Originally Posted by DrJon /img/forum/go_quote.gif
Looking at the innerfidelity data, I would consider it to be a little more complete representation of what we will actually hear.  If I'm reading it correctly, many frequencies are used and the resulting distortion is examined.  Plus there are 4 measurements- left and right, 90 and 100 db.  Not to mention the impulse and square wave data.  From these plots...

 
It is interesting that the headphone.com distortion graphs are generally much more optimistic (sometimes more than 10 times better) than the innerfidelity.com ones. I wonder if both are actually correct, how these were measured, and what sound pressure was used by HeadRoom ?