Dan Clark Stealth Review (State of the Art Headphone)

[Keith_W]

meaning: headphone measurements say very little ?

I did not say that. They do say a lot, but outside the <300Hz and >3000Hz range where most variability is demonstrated, the measurement may not correspond with what you actually hear. I am advocating caution when reading these headphone measurements, something a lot of people on ASR seem to forget. Amir reminds everyone not to read too much into headphone measurements in every headphone review, in bold type: "Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results." but ASR members keep forgetting that. Many think that what is measured is exactly what they will hear. As the above graph published by Olive shows, this may not be the case.

As an example, I found those Truthear x Crinacle Zeros to be bright and I had to EQ to tone them down. I know my experience is not generalizable because a lot of people here report that they like it. I also own a pair of DCA Stealths, which I bought after reading this review. My subjective impression is that they sound dull, even though it again complies to the Harman curve. Once again, it was probably variability between measurement and my head, nothing a bit of EQ to my taste can not fix. With my new target curve loaded into JRiver, the DCA Stealths sound wonderful.

BTW, I have performed hundreds of sine wave sweeps on my loudspeakers and I am pretty adept at predicting peaks (but not narrow Q nulls) just from hearing the sine wave sweep alone. I hear the sweep, estimate the peak to be around xxx Hz, and then look at the tracing. I also know my hearing is most sensitive within a certain range and my hearing can not reliably predict even a large deviation from target above 10-12kHz. My mic is much better than that for loudspeakers. For headphones, I play a sine wave sweep on my headphones and use that to help identify and cut down problem peaks. Of course, this is nowhere as good as a microphone, but then I don't own a headphone mic.

So - I have personally experienced two headphones that measurements assert compliance to the Harman curve, but one subjectively sounds bright, and the other sounds dull. I also know that this is a sample size of one, and you have no obligation to believe what I say (we are all good scientists here). I also know from reading a lot of subjective assessments of both headphones that many on ASR find no issue with brightness or dullness with either product. I do not discount any of those reports.

Given that my preference does not seem to match the published measurements, what could be the issue? Could it be that the measurements have limited generalizability between test fixtures and between heads? Was there a problem with the measurement, e.g. the method or the fixture? If the measurement is accurate and generalizable, then maybe I am the problem - could I be an outlier in that my personal preference does not match the Harman curve? Maybe I have some hearing loss with my advancing age? Is there a manufacturing defect with my sample? Is there some other reason, e.g. the equipment I am using or my level of intoxication? Of course, the honest answer is that all of the above are possible. Except the intoxication bit, because I have quit drinking In the end, I don't know the answer. Because I just EQ it to my preference, and if I am happy, that is all that matters.

 

[solderdude]

ASR members keep forgetting that. Many think that what is measured is exactly what they will hear. As the above graph published by Olive shows, this may not be the case.

Yep. Most people think if you get a 'flat' response (on a target) on a specific fixture that is an exact EQ. It isn't but may be a starting point for a lot of headphones.
Headphone measurements ≠ reality ≠ similar to electronics measurements ≠ speakers in a room but many do see it that way.

I just EQ it to my preference, and if I am happy, that is all that matters.

Yep, one can use the published 'EQ suggestions' as a starting point. That is usually better than nothing at all.
In the end, all that counts is that one likes the sound (for music enjoyment).
For creation of recordings, or reviewing, references and experience is an essential tool aside from some basic measurements.

 

[solderdude]

Iirc, the one outlier measurement is of another headphone that was placed on the graph by accident.

fixed it.... Thought this info was important enough to get right.
It shows that the Stealth (just like all other closed headphones) bass response is very seal dependent.
Above 3kHz the measurements are a crap shoot but.... (my theory) is that in practice this won't be as bad as the brain knows the 'variances' of the ear and on top of that will not perceive narrow peaks and dips as such anyway. The bass response is seal dependent and the reason why it won't sound 'Harman compliant' to them.

 

[markanini]

meaning: headphone measurements say very little ?

There are quite a few headphones (all open) that are not very seal dependent. The supplied data (up to several kHz) is quite reliable for those headphones.
Also quite a few planars do not change the lows much with some small seal issues.

So one can form an opinion on quite a lot of (not closed) headphones based on headphone measurements.
With IEM's there are also seal and insertion depth/comfort issues.

That said... I do agree that one should audition headphones or be able to return them if they don't suit you (sound or comfort wise)

Well said. Likewise I think measurements say something substantial, not quite the full picture. I learned from reading graphs that for the lower treble to sound neutral, if there are any peaks they must be no lower than 6kHz or else I don't bother auditioning. Excessive THD or also disqualifies a set for me, and I proceed with caution if the phase response is not normal. Everything else is at the very least EQ-able or program dependent, Harman is a good reference for the mids.

 

[Phoney]

Sean Olive has published on twitter the list of headphones involved in this study.

https://twitter.com/i/web/status/1630386678002225152

So yep, that's the Stealth :

View attachment 268949

Are those treble deviations partly due to unreliability in measurements in the upper treble region, or does open backs also vary alot from person to person in this area?

Edit: I guess @solderdude kind of answered this already.

 

[Phoney]

fixed it.... Thought this info was important enough to get right.
It shows that the Stealth (just like all other closed headphones) bass response is very seal dependent.
Above 3kHz the measurements are a crap shoot but.... (my theory) is that in practice this won't be as bad as the brain knows the 'variances' of the ear and on top of that will not perceive narrow peaks and dips as such anyway. The bass response is seal dependent and the reason why it won't sound 'Harman compliant' to them.

View attachment 268998

I've had someone whos read ALOT of the science tell me that it's especially an issue with planar closed backs, moreso than other type of closed backs. He mentioned something about acoustical impedance and gave me an explanation, but I don't really know what that means or remember exactly what he said. (we were discussing DCA headphones in this conversation)

 

[markanini]

Are those treble deviations partly due to unreliability in measurements in the upper treble region, or does open backs also vary alot from person to person in this area?

Far less.

 

[MayaTlab]

Tusind tak! Couldn't find any videos of the said speach. Would you happen to have any links?

No recording to my knowledge. Only the presentation's PDF is available. Sean seemed to have given a fairly similar presentation at CanJam NYC 2023, which may or may not have been recorded.

 

[MayaTlab]

Far less.

I think that this stops at 2kHz, unlike the more recent article published by Sean Olive.

 

[MayaTlab]

Are those treble deviations partly due to unreliability in measurements in the upper treble region, or does open backs also vary alot from person to person in this area?

Some conjectures from me :

I'd worry a bit more about it than @solderdude (unless I misunderstand his post) on the basis that if headphones reliably introduced variations at higher frequencies that naturally followed the individuals' anatomical features's influence on sound sources such as loudspeakers, you'd neither see for some of them large variations with positioning, nor would you see an inconsistant variation between the headphones measured by Harman in that paper (and nor would you see a significantly inconsistent transfer function at higher frequencies between headphones when measuring them from one rig to another BTW).

The way the data is presented prevents us from going into detail in that regard but it's fairly easy to eyeball it. These two headphones varied in the treble in an inconsistent way between individuals :

From my own experience with in-ear mics, I think that some of these variances could be caused by the positioning of the blocked ear canal entrance mics, particularly above a few kHz, but not all of it.

If the mics are past the ear canal entrance, and if all headphones were measured during the same session, with the microphones staying in the same place, the relative difference between headphones minus the effect of the ear canal's load should have been accurately captured, which is why at higher frequencies I'd have preferred to see the data presented in relative terms (pick one pair of headphones as a reference, measure the difference between it and the others, and compare how individuals differ in that regard), and would have preferred to know whether or not all headphones were measured at once without moving the mics.

Below 4-5kHz though I think that the mic's positioning should have a rather small effect, unless they failed to effectively block the ear canal, which makes the Stealth's variation in the 2-5kHz band (or at least, the inconsistencies between it and the K701 in that range) quite concerning as well (not just at lower frequencies).

The rest could arise from the interaction of a particular model of headphones with a singular individual, and that interaction could result in variations that are both going in the right direction (follow the individuals' (DF-ish?)HRTF) and the wrong direction (random).
Whether some headphones are more adept than others at interacting with a listener's anatomy in a way that maximises the desirable variations and minimises the random ones is... to my knowledge not very well documented (Rtings tried something in that vein with their PRTF tests but I'm not certain that it's fully developed). I would not be surprised to learn that this was one of the subjects of Alex Grell's presentation at CanJam NYC this year.

In regards to the question of headphones measurements, the above data, to me, means that this :

would be a lot more useful than this (which, given the above data, is made basically irrelevant) :

if it weren't for he K701's rather terrible sample variation .
Both headphones in my opinion are pretty good example of the two issues that are a blind spot in current reviews, coupling issues and sample variation, since both make any notion of target adherence on a fixture irrelevant to the end users' experience.

 

[solderdude]

Rtings has been measuring on human subjects (about 5 volunteers I reckon) and the differences are just a few dB in the treble and narrow BW.

My POV is: very narrow BW peaks are not heard as such and the brain is already used to certain peaks/dips anyway and constantly 'calibrates' itself to sounds all around us.
Of course, the position of a headphone on the head is also of big influence and is many, many dB in most cases anyway.
When one can position a headphone freely (think large pads, HD800, Ed XS, Austrian Audio etc) and also with most on-ears the sound can change from bright to dark even with a relatively small shift in position. One would think listeners would position their headphones the way they like it.

Problem with blocked ear canal measurements is that the test subject can't hear that optimal position due to a mic blocking most of the sound. This can lead to larger variations in the measurement plots than there would be in reality as one would position it better by ear.

But overall... yes... the graphs you see, even the ones made with the most expensive HATS by professionals, may or may not be how one hears it and any EQ based on that single plot (regardless if it was averaged or not) is not as exact as most believe it is.

The reason why I (and I believe Amir as well) think it is best to look for the biggest overall problems and only address those. The rest is 'character' of the headphone.
The fact that various headphones with the 'best EQ ever made' all still sound different (but closer to each other than without) with EQ is testimony of that.
All those small wiggles and bass adjustments may well be wrong but because one thinks it is 'very correct' one believes this is how it is supposed to sound (placebo also works for objectivists).

 

[MayaTlab]

Rtings has been measuring on human subjects (about 5 volunteers I reckon) and the differences are just a few dB in the treble and narrow BW.

The way I understand it, Rtings' consistency results above a few hundred Hz are the placement consistency over the fixture, not on humans.

Problem with blocked ear canal measurements is that the test subject can't hear that optimal position due to a mic blocking most of the sound. This can lead to larger variations in the measurement plots than there would be in reality as one would position it better by ear.

Yep, but on the other hand one's sense of touch is something that you don't get when measuring on a fixture. I've found it surprisingly easy to consistently place headphones on my head with in-ear mics (a lot more so than on my useless KB0065 clone rig). Whether that would apply to test subjects unfamiliar with the headphones tested in a study could be different (personally if I were to conduct such a test I'd ask the subjects to acclimatise themselves with the various headphones first, before measuring them in situ).

 

[isostasy]

@MayaTlab Was a HRTF taken from the human test subjects in the listening room with speakers? What I'm struggling to understand currently is how any meaningful conclusion can be drawn from comparing blocked ear canal measurements when it is not know which variances arise from anatomical features, which would also present when listening to speakers in the listening room? What we want to know is which headphones consistently match the particular target curve for each specific listener, without introducing other variances in frequency response which cannot be put down to the listener's HRTF. In other words, I don't care if a particular headphone doesn't measure the same on different heads, or indeed whether it measures the same as on a test fixture as on a human head; what I want to know is whether a headphone which measures well on a test fixture doesn't interact with human ears in a wildly unpredictable fashion. The measurements above don't mean anything in this regard, because I don't know whether the variations in the Stealth or the K701 measurements are closer or further from the variations that would arise from difference in the human test subjects' HRTF. In other words, sure, measurements showing variation in the Stealth's response as low as 2kHz look bad, but how do we know whether this is actually bad, a result of positioning or poor design, or actually really good, in that it's better demonstrating interaction with the human test subject's anatomy and therefore closer to how they would perceive speakers in a room?

 

[MayaTlab]

@MayaTlab Was a HRTF taken from the human test subjects in the listening room with speakers?

I don't think that it has been mentioned, but I'd be very surprised if that wasn't one way or another ongoing research at Harman (and other companies such as Apple for example).

What I'm struggling to understand currently is how any meaningful conclusion can be drawn from comparing blocked ear canal measurements when it is not know which variances arise from anatomical features, which would also present when listening to speakers in the listening room? What we want to know is which headphones consistently match the particular target curve for each specific listener, without introducing other variances in frequency response which cannot be put down to the listener's HRTF. In other words, I don't care if a particular headphone doesn't measure the same on different heads, or indeed whether it measures the same as on a test fixture as on a human head; what I want to know is whether a headphone which measures well on a test fixture doesn't interact with human ears in a wildly unpredictable fashion. The measurements above don't mean anything in this regard, because I don't know whether the variations in the Stealth or the K701 measurements are closer or further from the variations that would arise from difference in the human test subjects' HRTF. In other words, sure, measurements showing variation in the Stealth's response as low as 2kHz look bad, but how do we know whether this is actually bad, a result of positioning or poor design, or actually really good, in that it's better demonstrating interaction with the human test subject's anatomy and therefore closer to how they would perceive speakers in a room?

We don't, and that's the issue. However picture me skeptical that the 5-6dB variation in the 2-5kHz range for the Stealth is of the "desirable" kind.

What we do know, comparing the K701 and Stealth above, is that, logically, at least one of these two necessarily is "wrong" since it is inconsistent with the other. And probably both honestly.

What this data would also enable us to know (but not presented in this way) is whether or not you can apply a constant transfer function between each headphones' average on real humans and ear simulators (in other words not just whether or not a pair of headphones vary more or differently than another, but also whether the averages on real humans deviate from ear simulator in a constant way or not).

 

[truckers_atlas]

I got to try the Stealth at CanJam and I was surprised but I did not end up enjoying them at all. I am not sure what the culprit was for this. The amp was a feliks audio and it certainly had sufficient power for them.

They just seemed very restrained across the board and particularly anemic for bassy tracks. Perhaps I enjoy a more colored representation? Or maybe I needed time to adjust to their sound signature.

I much preferred the ZMF Atrium closed. Even the Focal Stellia which are cheaper.

You're not alone here in being disappointed with the Stealth. When I demoed the Stealth, it just sounded off. The Stealth had zero impact despite the Stealth having the Harman bass shelf built in. I much preferred the Aeon 2 Closed with perforated pads, which is essentially an Aeon 2 Noire in red, to the Stealth.

 

[Keith_W]

I have to report the same. I have had an opportunity to compare my Stealths to the cheaper Focal Stellias a few times. The Stellias are much more sensitive and easy to drive which means (1) they are easier to find amplification for, and (2) I have to be careful to volume match when I am doing A-B's between the two headphones. I have no way to measure the output of both headphones, so I played a 1kHz sine wave and twiddled the volume knob on my amp until they sounded the same. Then I took note of the position of the volume pot and started listening across a range of music.

These are my subjective impressions only. Apologies, because I am unable to offer anything else. There are obvious differences in tonal balance. The Stellia has a more U-shaped curve, with more bass and more treble. They also compress when driven to high volumes. I am unable to get my Stealths to compress, because my amp does not have the ability to drive them to ear splitting levels, only "slightly too loud" levels. When both are driven to "slightly too loud", the Stellia sounds more dynamic with transients. Overall the Stealth sounds overdamped compared to the Stellia. Whilst I can EQ both headphones to deliver the same frequency response, there is nothing I can do to reduce the overdamped sound of the Stealth.

The downside of the Stellias would be the styling and the inability to fold to a tiny size for travelling. But to my ears they do sound better.

 

[majingotan]

I have to report the same. I have had an opportunity to compare my Stealths to the cheaper Focal Stellias a few times. The Stellias are much more sensitive and easy to drive which means (1) they are easier to find amplification for, and (2) I have to be careful to volume match when I am doing A-B's between the two headphones. I have no way to measure the output of both headphones, so I played a 1kHz sine wave and twiddled the volume knob on my amp until they sounded the same. Then I took note of the position of the volume pot and started listening across a range of music.

These are my subjective impressions only. Apologies, because I am unable to offer anything else. There are obvious differences in tonal balance. The Stellia has a more U-shaped curve, with more bass and more treble. They also compress when driven to high volumes. I am unable to get my Stealths to compress, because my amp does not have the ability to drive them to ear splitting levels, only "slightly too loud" levels. When both are driven to "slightly too loud", the Stellia sounds more dynamic with transients. Overall the Stealth sounds overdamped compared to the Stellia. Whilst I can EQ both headphones to deliver the same frequency response, there is nothing I can do to reduce the overdamped sound of the Stealth.

The downside of the Stellias would be the styling and the inability to fold to a tiny size for travelling. But to my ears they do sound better.

Disagree. To my ears, I subjectively find the Expanse and Stealth more dynamic, more impact, snappier in transients, more refined, better macro and microdyamics than Stellia. They’re on par with the Utopia in this regard to my ears. Heck even my Aeon X open sounded more dynamic, punchier, better tonal contrast than Stellia and definitely 99% of Stealth, Expanse and Utopia’s technicalities. The low distortion aspect of DCA headphone brings incredible realism to the instruments that I was teary eyed with my listening session earlier from the extremely impressive and the most lifelike sonic performance that I ever heard minus the Warwick Aperio, and that’s with my Aeon X Open (best subjective sounding 400 USD headphone to me. S+++ class for the price/performance value)

 

[Grobbelboy]

I’m pretty certain that the “overdamped” complaints mainly stem from the positioning of the cups over the ears. The FR of both the Stealth and Expanse seems to be very susceptible to change depending on the placement of the cups, more than any other over ear HP I know of at least. My Expanse definitely has a slightly muffled sound when not positioned properly and only start to sound truly fantastic with my ears placed as far to the front as possible.

 

[Keith_W]

I’m pretty certain that the “overdamped” complaints mainly stem from the positioning of the cups over the ears. The FR of both the Stealth and Expanse seems to be more susceptible to change depending on the placement of the cups than any other over ear HP I know of. My Expanse definitely has a slightly muffled sound when not positioned properly and only start to sound truly fantastic with my ears placed as far to the front as possible.

I just tried it. Placing my ears to the front of the cups causes the soundstage to shift to the rear and makes it sound less "open" which was the reason I bought the Stealths. It does not make it sound less damped. It might just be my ears and my head.

 

[Benesyed]

You're not alone here in being disappointed with the Stealth. When I demoed the Stealth, it just sounded off. The Stealth had zero impact despite the Stealth having the Harman bass shelf built in. I much preferred the Aeon 2 Closed with perforated pads, which is essentially an Aeon 2 Noire in red, to the Stealth.

I preferred the senheisser 800s to the stealth by a large margin which I was shocked to find.


one last point that I'll make that isn't related to sound quality is that I did not find them comfortable either like any other people mentioned. the headband system has a lot of jaw clamping force on my head and for me personally was the worst of any that I had tried up till now. It's possible that the discomfort colored my acoustic judgment unconsciously but ultimately that fact doesn't really matter because if I perceive it to sound poor and it feels poor it doesn't actually matter because that's the end result that I'm getting. I would definitely audition these from somewhere that gives you a good return policy. as much as I dislike Amazon it does offer very hassle for your returns that are useful in this case.