Lowest Distortion Headphones
Jun 13, 2018 at 1:01 PM Post #17 of 37
From what you know and measurements you did or found online - which was the one with the least distortion?
(Usually there are only measurements of harmonic distortion)

Some likely contenders:
Audeze LCD2 (not all, but some)
HifiMan RE-400\600
Audeze iSine 10\20\LCDi4(?)
Stax SR-202\SR-404
Sennheiser HD650 have low THD from 250Hz and up
Focal Utopia

And what is the most current research regarding hearing threshold when it comes to harmonic distortion? (as a function of the harmonic (2nd, 3rd etc'...), amplitude, frequency...)

*I am aware of the fact that it isn't the ultimate way to predict headphones' sound quality.

At the level of auditory perception, I expect low distortion to translate in clarity, resolution, detail, smoothness, etc. In my experience, planar magnetics and electrostatics will do well in that regard, and some dynamic drivers also.

Considering the headphones you listed, I'd also consider the LCD-3 and LCD-4, and the Focal Elear and Clear.
 
Jun 13, 2018 at 2:13 PM Post #18 of 37
At the level of auditory perception, I expect low distortion to translate in clarity, resolution, detail, smoothness, etc. In my experience, planar magnetics and electrostatics will do well in that regard, and some dynamic drivers also.

Considering the headphones you listed, I'd also consider the LCD-3 and LCD-4, and the Focal Elear and Clear.
I've seen people describe amps with more than 4%THD as having great resolution, details, and smoothness. ^_^ it's not really that simple to assume correlation between subjective impressions and distortions. we have some rule of thumb about magnitudes and how even or odd harmonics tend to feel euphonic or not, but that's about it. distortions can reach a maximum at different frequencies, come along some nasty spikes or just blend in. add some smoothness, or add some harshness. feel like a veil or feel like extra texture that some will interpret as more details. also when comparing headphones already stable well below 1%THD, we can start questioning if people will really notice much of a change.
based on my very unreliable experiences and so very anecdotal results, I'd bet that the FR probably still plays the main part in those impressions of clarity, detail... (for headphones which aren't crippled with massive distortions).
 
Jun 13, 2018 at 3:07 PM Post #19 of 37
I've seen people describe amps with more than 4%THD as having great resolution, details, and smoothness. ^_^ it's not really that simple to assume correlation between subjective impressions and distortions. we have some rule of thumb about magnitudes and how even or odd harmonics tend to feel euphonic or not, but that's about it. distortions can reach a maximum at different frequencies, come along some nasty spikes or just blend in. add some smoothness, or add some harshness. feel like a veil or feel like extra texture that some will interpret as more details. also when comparing headphones already stable well below 1%THD, we can start questioning if people will really notice much of a change.
based on my very unreliable experiences and so very anecdotal results, I'd bet that the FR probably still plays the main part in those impressions of clarity, detail... (for headphones which aren't crippled with massive distortions).

Understood, but I'm not sure that THD is the best distortion measure to try to correlate with perception. It seems to depend on how the drivers mechanically handle a complex music signal, with multiple vibration frequencies interacting with each other. How is THD typically measured with headphones?

This is the sort of thing I'm referring to:

http://www.audioxpress.com/article/Measurement-and-Perception-of-Regular-Loudspeaker-Distortion

"Unfortunately, harmonic distortion measurement does not give a comprehensive picture of the large signal performance of loudspeaker systems. At least a second tone is required to generate intermodulation products which occur at difference and sum frequencies in all possible combinations of the excitation frequencies. Increasing the number of fundamental components in multi-tone stimulus will generate more and more intermodulation components spreading over the complete audio band. Contrary to the THD response in Fig. 9, the nonlinear force factor Bl(x) and the inductance L(x) THD generate significant intermodulation distortion at higher frequencies as illustrated in Fig. 10.

Thus, harmonic distortion measurements using a single test tone are not sufficient for assessing loudspeakers comprehensively and predicting the large signal performance for complex stimuli like music."​
 
Last edited:
Jun 14, 2018 at 5:06 AM Post #20 of 37
that's exactly what I'm talking about. how often do you see more than super basic THD specs for headphones? and even that is not something the manufacturers provide very often. so aside from audiophile's unwarranted intuition that higher fidelity will have all the qualities we dream about, and some very crude notions about huge variations in distortions and how they tend to feel, how do we know or test how changes in distortions actually affect our impressions of the headphone? it's a really tricky thing IMO.

about how it's measured, the principle is always the same. generate a single tone and look at all the harmonics created from that single tone. beyond that, the method and the way the results are given can change a good deal. I won't start whining about how easy it is for a manufacturer to give meaningless specs that look better than they are. it's almost always like that anyway. you may have one percentage value for 1khz or some almost meaningless stuff like that. you may have a frequency plot showing THD+N. you can have graphs with a plot for each harmonic. and as always, weighted curves can be applied. you can have a graph with the measured stuff, or one with the FR of the headphone as reference of flat. in that case, as simply defining what is flat for the FR is a free game for everybody, you end up being able to directly change the shape of the THD graph if you go for that option.
so in the end like with most things, those specs really become relevant when they're compared to other headphones measured on the same gear using the same conditions. ambient noise might be a PITA to keep consistent obviously, and with harmonics often starting 40 or 50dB below signal, when you measure a test tone at 90dB SPL, what we measure is not that far away from ambient noises in a city. so it's one of those tests available to anybody, but most people won't have the necessary gear and conditions to do really meaningful measurements where the result is just the headphone. the corollary being that the sound created by those distortions is usually pretty quiet and well below music. so once again, they're less likely to be the main reason why we feel a certain way about the sound. a change in frequency response, which is affecting even the loudest part of music, is more likely to really change our impressions, IMO, and within reasonable specs of course. stuff going horribly wrong will feel horribly wrong.
 
Jun 14, 2018 at 6:42 AM Post #21 of 37
^ That’s why I focus on the mechanics of the driver technology rather than relying on distortion measurements which may not capture the actual distortions.
 
Jun 14, 2018 at 1:07 PM Post #22 of 37
Back when I first started out with hifi in the early 70s, distortion was a big issue. It was frequently audible and it piled up in layers from LP to amp to transducer. With current technology, it's been reduced to the point where it really isn't an issue any more.
 
Last edited:
Jun 14, 2018 at 1:32 PM Post #23 of 37
Back when I first started out with hifi in the early 70s, distortion was a big issue. It was frequently audible and it piled up in layers from LP to amp to transducer. With current technology, it's been reduced to the point where it really isn't an issue any more.

Distortion not an issue with transducers? I don't see how that's possible.
 
Jun 14, 2018 at 2:08 PM Post #24 of 37
There are a lot of transducers with distortion below the threshold of audibility under music. The threshold for speakers is somewhere around 3% (-30dB). (That's a ballpark figure for sure, but it is a good rule of thumb.) Headphones are much easier to find with low distortion, but there are a lot of decent speakers out there that qualify too. Most speaker manufacturers don't publish THD specs though, and it's difficult to measure accurately anyway. Hence, the rule of thumb rather than hard and fast lines in the sand.

But for good quality headphones and speakers distortion has pretty much crossed the line from "I can hear it. Fix it." to "I don't know if I can hear it, but a lower distortion measurement *must* sound better, right?" That's when you know where a real problem crosses over into woo worries for high end audio to milk. Obviously, not everything has good distortion levels, but it isn't hard to find great performance if you look for it.

Personally, I find that sound quality is dependent on the balance of all of the various specs, not the abstract numbers for any given spec. That said, most problems with transducers I have run into are response imbalances.
 
Last edited:
Jun 14, 2018 at 3:01 PM Post #25 of 37
well I'm sure if we go full Amir about it, we could very easily show situations where even 0.1%THD is noticeable. so I would be cautious about saying that we have a lot of transducers with distos below audibility.
on the other hand with most musics it can be pretty hard to notice stuff below 1%THD. after all, musical instruments generate their own fair share of harmonics, so it's not really surprising that HD from the headphone can end up masked.
so I'm saying no, and yes at the same time. I'm crazy I do what I want ^_^.
 
Jun 14, 2018 at 3:08 PM Post #26 of 37
1% is rule of thumb for headphones. Speakers are more forgiving.
 
Jun 14, 2018 at 5:28 PM Post #27 of 37
Transducers can have multiple types of distortion related to how the diaphragm vibrates with a complex music signal, and how the geometry and movement of the diaphragm generates sound waves. I don't see how standard distortion measurements are going to capture all that adequately.
 
Jun 14, 2018 at 5:36 PM Post #28 of 37
Transducers can have multiple types of distortion related to how the diaphragm vibrates with a complex music signal, and how the geometry and movement of the diaphragm generates sound waves. I don't see how standard distortion measurements are going to capture all that adequately.

Yeah, that's why you just go with ballpark figures. But thankfully, with good headphones and speakers, it isn't a really significant issue. Human ears are pretty forgiving to the types and degree of distortion in quality modern transducers.
 
Jun 14, 2018 at 7:07 PM Post #29 of 37
There are a lot of transducers with distortion below the threshold of audibility under music. The threshold for speakers is somewhere around 3% (-30dB). (That's a ballpark figure for sure, but it is a good rule of thumb.) Headphones are much easier to find with low distortion, but there are a lot of decent speakers out there that qualify too. Most speaker manufacturers don't publish THD specs though, and it's difficult to measure accurately anyway. Hence, the rule of thumb rather than hard and fast lines in the sand.

But for good quality headphones and speakers distortion has pretty much crossed the line from "I can hear it. Fix it." to "I don't know if I can hear it, but a lower distortion measurement *must* sound better, right?" That's when you know where a real problem crosses over into woo worries for high end audio to milk. Obviously, not everything has good distortion levels, but it isn't hard to find great performance if you look for it.

Personally, I find that sound quality is dependent on the balance of all of the various specs, not the abstract numbers for any given spec. That said, most problems with transducers I have run into are response imbalances.
Yep....a lot of those response imbalances can be ameliorated with placement specific to the speaker design.....suspect i'm preachin to the choir here....a bad room or placement will introduce more problems than a little THD.
 
Jun 18, 2018 at 12:07 AM Post #30 of 37
I think I remember that our ears are very forgiving of THD, but intermodulation distortion is perceivable at much lower levels. I think THD usually comes for the most part out of the transducers, while IM distortion usually comes from electronics. What's fun is really cranking up your guitar amp for some really serious THD.
 

Users who are viewing this thread

Back
Top