Hifiman Ananda Stealth V2 Headphone Review

[Blorg]

@Robbo99999 right and flat is a very good result, that's what I'm saying. 560S doesn't have a Harman bass shelf. I haven't heard it, it does look very well tuned. Most seem to put the HD600 and HD650 above it though, despite being further away from Harman in that regard. The Expanse I mentioned at one of the very very few well regarded open backs that actually has Harman bass but I believe they do this with passive electronics which impacts on the drivability and possibly other aspects. I haven't heard it though.

 

[CedarX]

My more general point, though, is that a totally flat bass extension from an open back is extremely good, and for that matter there are even pretty universally acclaimed headphones that don't even have that, but have a roll-off (most dynamic drivers).

Isn't it inherently controversial? "Bass" weight significantly in the perception of sound quality, yet "preferences" in the bass area are very (highly?) variable and most music bass content drops significantly on the very low end... AFAIK, Harman research acknowledges this, recognizing that some individuals just like moar bass and, I believe the preference score ignoring <50 Hz (not 100% sure)
I like Amir's approach of evaluating first the HP against the target ("as-is") and then looking at "EQ-abilty" if it is deviating significantly from the target.

 

[Blorg]

Isn't it inherently controversial? "Bass" weight significantly in the perception of sound quality, yet "preferences" in the bass area are very (highly?) variable and most music bass content drops significantly on the very low end... AFAIK, Harman research acknowledges this, recognizing that some individuals just like moar bass and, I believe the preference score ignoring <50 Hz (not 100% sure)
I like Amir's approach of evaluating first the HP against the target ("as-is") and then looking at "EQ-abilty" if it is deviating significantly from the target.

This is the thing though, totally flat bass is the easiest to EQ the way you want it... Easier than a shelf, and a lot easier than a roll-off, as you are more likely to run into distortion or power issues boosting than cutting. Bear in mind most people don't have measuring rigs and unit variance is a thing, so it can be quite hard to EQ from other people's measurements. I got a rig for IEMs and it has been fantastic, that I can now EQ very exactly for my own actual unit, and confirm results, or what different tips or mods do.

My own personal feeling, very low sub bass is not that audible and I won't do drastic 10dB+ adjustments to bring up a roll off, I'll just add a shelf and let it go in the lower regions. Sometimes it takes another big boost at 20-30Hz to get something up to Harman there, I'll just leave it out. But flat is still easier and preferable. It depends the size of the roll off, too, I have both of these and the Stealth does perceptibly have better bass than the original did.

 

[Robbo99999]

@Robbo99999 right and flat is a very good result, that's what I'm saying. 560S doesn't have a Harman bass shelf. I haven't heard it, it does look very well tuned. Most seem to put the HD600 and HD650 above it though, despite being further away from Harman in that regard. The Expanse I mentioned at one of the very very few well regarded open backs that actually has Harman bass but I believe they do this with passive electronics which impacts on the drivability and possibly other aspects. I haven't heard it though.

I agree, except it depends who you talk to re HD560s vs HD600/650. I have HD600 & HD560s and HD560s is miles better for me, people vary though. There's quite a few people here that like HD560s better than HD600/650, we have to judge on our own experiences though.

 

[Robbo99999]

This is the thing though, totally flat bass is the easiest to EQ the way you want it... Easier than a shelf, and a lot easier than a roll-off, as you are more likely to run into distortion or power issues boosting than cutting. Bear in mind most people don't have measuring rigs and unit variance is a thing, so it can be quite hard to EQ from other people's measurements. I got a rig for IEMs and it has been fantastic, that I can now EQ very exactly for my own actual unit, and confirm results, or what different tips or mods do.

My own personal feeling, very low sub bass is not that audible and I won't do drastic 10dB+ adjustments to bring up a roll off, I'll just add a shelf and let it go in the lower regions. Sometimes it takes another big boost at 20-30Hz to get something up to Harman there, I'll just leave it out. But flat is still easier and preferable. It depends the size of the roll off, too, I have both of these and the Stealth does perceptibly have better bass than the original did.

I do the same, inasmuch that headphones that are rolled off in the bass I'll only try to get 30Hz (or 35Hz depending on how rolled off they are) to Harman and then I'll let it roll off naturally under that.

 

[CedarX]

I agree, except it depends who you talk to re HD560s vs HD600/650. I have HD600 & HD560s and HD560s is miles better for me, people vary though. There's quite a few people here that like HD560s better than HD600/650, we have to judge on our own experiences though.

I have all three... My (subjective) preference "as-is": HD650. After EQ: HD560S. But, I'll readily admit that I could not EQ HD560S to a satisfactory level by ear only; looking at measurements and suggested EQ was key.
So @Blorg made a good point about the ease of EQ. Headphones evaluation should be a 3-steps process: 1/ raw FR & deviation from target, 2/ EQ-ability (is it salvageable?), and 3/ How easy it is to EQ.

Ananda biggest issue may not be so much the flat bass--it is easy to EQ to whatever you like--but the "complex filter recipe" it requires in the highs to reach Amir's recommended level.

 

[HoJ76]

Replaced my he400iver2020 today.

 

[Maiky76]

This is a review, listening tests, EQ and detailed measurements of the Hifiman Ananda Stealth V2 open back headphone. It is on kind loan from a member and costs US $399.
View attachment 338437
It is typical Hifiman large cup configuration that seems to assume you ear are twice as long as they really are! If find the headphone attractive and comfortable to wear.

Let's measure its response using GRAS 45CA driving by Audio Precision APx555 analyzer. If you are new to my headphone measurements, I highly recommend that you watch my video tutorial on headphone measurements.

Hifiman Ananda Stealth V2 Measurements
Let's start with our headphone frequency response measurements in the context of most preferred target response:
View attachment 338438
It is clear to see the bass deficiency. Response also gets wavy from 500 Hz to 1 kHz and then we have some short fall in lower treble. Response then becomes cyclical with peaks that exceed our target. Net results is likely a flat and slightly bright sound signature. Subtracting the two curves gives us the areas we need to correct with equalization:
View attachment 338439

The relative distortion graph has a lot of fuzziness:
View attachment 338441

The peak around 6 kHz seems like a clear design issue. But the roughness between 500 Hz and 3 kHz is odd and made me wonder if there is some room reflections. I rotated my fixture but it made no difference even though that made a substantial difference as far as reflections. I swapped the cups the other way around the distortions tracked the left channel so not a room issue. I then checked the other channel and surprisingly, was much cleaner:
View attachment 338442
Notice how at 94 dBSPL (blue), there is essentially no distortion from 500 Hz to 4 kHz. This says there is some serious quality control issue here. Even beyond that, we have bass distortion that goes out of control at 114 dBSPL and again, around 6 kHz. Latter which likely is a series of resonances, should have been found and fixed during development as it has such a clear signature.

Edit: forgot to include the absolute distortion level graph:

View attachment 338458

Group delay is messy, no doubt due to the distortions we saw above:
View attachment 338443

Impedance is flat and low as planar magnetic drivers are usually so:

View attachment 338444

I zoomed way in (inset) and we clearly see impedance changing due to resonance around 6.2 kHz. There are other peaks in there as well. So you don't even need the distortion test to know there is something here to be fixed.

Good news is that this is a fairly sensitive headphone which combined with low impedance should make it relatively easy to drive:
View attachment 338446

Hifiman Ananda Stealth V2 Listening Tests and Equalization
First impression was "OK" with glassy, flat sound with a tinge of brightness. That impression grew more negative once I developed the full set of filters and performed AB tests:

View attachment 338448
The bass correction which took two filters to shape it as inverse of headphone response was a given. This added warm and by itself made a good improvement. I then dialed in the filters up to 5 and sound was much improved but still needed some work. I am loathe normally in making corrections above those frequencies but here, I found it quite useful to remove some grittiness from the high frequencies.

Once the complex filter recipe was in place, the improvements were dramatic. Sub-bass response was excellent (a surprised due to high level of distortion). High frequencies were now much cleaner and balanced. And spatial qualities improved as well which is a strong feature of these large cups.

Conclusions
Objective measurements clearly show design issues and decisions. Even if you accept the tonality as is, there is no excuse for high levels of distortion at focused energies which indicate resonances. This is topped with one channel distorting much more than the other in critical area of our hearing. So by any measure, pun intended, this is a flawed headphone. Fortunately the out of box response is not annoying and with EQ, you get a nice transformation to something resembling highly performant headphone.

I can only recommend the Hifiman Ananda Stealth V2 with equalization.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Here are some thoughts about the EQ.

Please report your findings, positive or negative!

Notes about the EQ design:

• The average L/R is used to calculate the score.
• The resolution is 12 points per octave interpolated from the raw data (provided by @amirm)
• A Genetic Algorithm is used to optimize the EQ.
• The EQ Score is designed to MAXIMIZE the Score WHILE fitting the Harman target curve (and other constrains) with a fixed complexity.
  This will avoid weird results if one only optimizes for the Score.
  It will probably flatten the Error regression doing so, the tonal balance should be therefore more neutral.
• The EQs are starting point and may require tuning (certainly at LF and maybe at HF).
• The range around and above 10kHz is usually not EQed unless smooth enough to do so.
• I am using PEQ (PK) as from my experience the definition is more consistent across different DSP/platform implementations than shelves.
• With some HP/amp combo, the boosts and preamp gain (loss of Dynamic range) need to be carefully considered to avoid issues with, amongst other things, too low a Max SPL or damaging your device. You have beed warned.
• Not all units of the same product are made equal. The EQ is based on the measurements of a single unit. YMMV with regards to the very unit you are trying this EQ on.
• I sometimes use variations of the Harman curve for some reasons. See rational here: https://www.audiosciencereview.com/...pro-review-headphone.28244/page-5#post-989169
• https://www.audiosciencereview.com/...pro-review-headphone.28244/page-6#post-992119
• NOTE: the score then calculated is not comparable to the scores derived from the default Harman target curve if not otherwise noted.

Good L/R match.

I have generated one EQ, the APO config file is attached.

Score no EQ: 77.9
Score Amirm: 75.3
Score with EQ: 78.5

Score limited by the trough at 10kHz.
Interested to see the subject comments as the scores are really close but the responses maybe different enough to be separated.

Hifiman Ananda  APO Score EQ Full Flat@HF 96000Hz
March072024-160650

Preamp: -5.6 dB

Filter 1: ON PK Fc 19.80 Hz Gain 5.56 dB Q 0.33
Filter 2: ON PK Fc 194.54 Hz Gain -1.72 dB Q 1.15
Filter 3: ON PK Fc 910.97 Hz Gain -2.17 dB Q 1.84
Filter 4: ON PK Fc 1626.18 Hz Gain 4.35 dB Q 1.03
Filter 5: ON PK Fc 3137.99 Hz Gain -3.25 dB Q 3.04
Filter 6: ON PK Fc 5254.58 Hz Gain 7.35 dB Q 5.49
Filter 7: ON PK Fc 6658.09 Hz Gain -4.09 dB Q 2.09
Filter 8: ON PK Fc 12817.13 Hz Gain -8.20 dB Q 7.91