Hifiman Sundara Review (headphone)

[0RF30]

Those are measurements of the pre-2020 revision of the Sundara. Here are the measurements of the latest revision, which look even more similar to Amir's review
View attachment 127231

Those are old pads version measurements. 2020 version with pad revision : https://www.dropbox.com/s/o3fza1a4kmmy4vr/Hifiman Sundara (2020 revised earpads).pdf?dl=0 , but oratory1990 only made the EQ for this version, not measurements.

 

[Manolo0707]

I'm listening to music on my Sundara set tonight and am continually delighted with them. I tried Oratory's EQ vs. Amir's and realized they have different pre-amp gain, giving myself an instant reminder of why level matching is so critical in comparisons! I do give a slight edge in preference to the 9 band PEQ Oratory provided over Amir's, but commend him for getting most of the way with only 3 bands of correction.

I'm a former Grado owner, and their over-emphasized treble and midrange gave good clarity on music. For me, the Sundara was like "graduating" from Grado into a set that just does everything better. All cliches aside, my wife took a listen to the EQ'd Sundara tonight and said "I really liked your Grados and listened to them all the time when you weren't home, but these are just so much better and my comfortable." Spot on.

I'm also a huge fan of moode + CamillaDSP on the Raspberry Pi. I'm sending music from my iphone via Airplay and it just works so well. It's also freed up a MiniDSP to other applications, since this Raspberry Pi can do basically anything I need it to do on DSP now for a simple system. Fantastic... but not the thread for talking it up more!

Can you EQ in using that system?

 

[0RF30]

oratory1990 just updated his EQ for Sundara, previous is no longer available : https://www.dropbox.com/s/o3fza1a4kmmy4vr/Hifiman Sundara (2020 revised earpads).pdf?dl=0


To keep trace of the old one :

Channel: all
Preamp: -7 dB
Filter 1: ON PK Fc 28 Hz Gain 2 dB Q 1.4
Filter 2: ON LSC Fc 105 Hz Gain 5 dB Q 0.71
Filter 3: ON PK Fc 510 Hz Gain 1.3 dB Q 2
Filter 4: ON PK Fc 1250 Hz Gain -1.6 dB Q 1.2
Filter 5: ON PK Fc 2400 Hz Gain 3.5 dB Q 0.9
Filter 6: ON PK Fc 4800 Hz Gain -2.7 dB Q 3.5
Filter 7: ON PK Fc 6100 Hz Gain 3.5 dB Q 1.4
Filter 8: ON PK Fc 6500 Hz Gain -2 dB Q 6
Filter 9: ON PK Fc 10400 Hz Gain -2 dB Q 6

Filter 2 is a low shelf, others peaks.


New one is intended to be taste customizable in diverse areas. If you do so, don't forget to modify preamp value to avoid clipping. With Peace/APO, value is easy to find, it's the value on top right corner of the graph. Suggested +7db sub shelf for linear sub extension is good if you have enough power to adjust the preamp (-12.4 db in this case). I also adjusted the high shelf to tame some harshness.

 

[bobbooo]

New one is intended to be taste customizable in diverse areas. If you do so, don't forget to modify preamp value to avoid clipping. With Peace/APO, value is easy to find, it's the value on top right corner of the graph. Suggested +7db sub shelf for linear sub extension is good if you have enough power to adjust the preamp (-12.4 db in this case).

Looks like this is from a new measurement he's done himself, instead of using a measurement by @Resolve previously, which also means Oratory would have listened to them and fine-tuned his EQ accordingly, unlike before. I suspect he's limited the default bass boost to under the target for a reason - the stock response at 20 Hz is a whopping 11.5 dB under target (possibly due to sealing issues, maybe the pads or the lack of swivel causing this), so maybe boosting by that much adds audible distortion. Note HifiMan's HE4XX have better sub-bass extension so don't have this problem, Oratory boosting them right up to the target at 20 Hz. At almost half the price of the Sundara, the HE4XX seem like a better buy really.

 

[0RF30]

Looks like this is from a new measurement he's done himself, instead of using a measurement by @Resolve previously. I suspect he's limited the default bass boost to under the target for a reason - the stock response at 20 Hz is a whopping 11.5 dB under target (possibly due to sealing issues, maybe the pads or the lack of swivel causing this), so maybe boosting by that much adds audible distortion. Note HifiMan's HE4XX have better sub-bass extension so don't have this problem, Oratory boosting them right up to the target at 20 Hz. At almost half the price of the Sundara, the HE4XX seem like a much better buy really.

You're right, I previously stated he didn't make the measurements himself for the previous version.
Regarding the added distortion of the bass boost, you'll get there only when these frequencies are used in your tracks, usually I don't care about some light bass distortion in the concerned genders (hip-hop, electro), the lack of sub bass is more problematic for me in these cases.
HE-4XX has better bass extension out of the box (oratory already modified his EQ if you didn't noticed ), but is muddy in comparison with Sundara and 2020 HE-400i. Better bass extension out of the box doesn't necessary mean less distortion when you play with bass EQ... EQed Sundara and EQed 2020 HE-400i sound a lot cleaner than EQed HE-4XX.
EQed 2020 HE-400i is the real deal IMO if you want to save the extra money.

 

[bobbooo]

You're right, I previously stated he didn't make the measurements himself for the previous version.
Regarding the added distortion of the bass boost, you'll get there only when these frequencies are used in your tracks, usually I don't care about some light bass distortion in the concerned genders (hip-hop, electro), the lack of sub bass is more problematic for me in these cases.
HE-4XX has better bass extension out of the box (oratory already modified his EQ if you didn't noticed ), but is muddy in comparison with Sundara and 2020 HE-400i. Better bass extension out of the box doesn't necessary mean less distortion when you play with bass EQ...
EQed 2020 HE-400i is the real deal IMO if you want to save the extra money.

View attachment 127352

That supposed (comparative) muddiness is not supported by the measurements in any way whatsoever:

In fact quite the opposite, with the HE400i lacking in the upper-mids / treble, and with worse high-frequency extension. Unless you consider the better bass extension of the HE4XX 'muddiness'

As for the HE4XX's distortion, that's nice and low too:

So I suspect subconscious cognitive bias is at play here. I've seen a similar pattern with other Drop-branded headphones receiving negative judgements compared to non-Drop models that's not backed up by measurements (notably the Sennheiser HD6XX, which some people still claim sounds inferior to the HD650, despite them being identical apart from the paint job).

 

[0RF30]

That supposed (comparative) muddiness is not supported by the measurements in any way whatsoever:

View attachment 127356

In fact quite the opposite, with the HE400i lacking in the upper-mids / treble, and with worse high-frequency extension. Unless you consider the better bass extension of the HE4XX 'muddiness'

As for the HE4XX's distortion, that's nice and low too:

So I suspect subconscious cognitive bias is at play here. I've seen a similar pattern with other Drop-branded headphones receiving negative judgements not backed up by measurements (notably the Sennheiser HD6XX, which some people still claim sounds inferior to the HD650, despite them being identical apart from the paint job).

I was talking about EQed comparisons (you stated yourself EQ in sub bass region could add distortion), and about what my poor and tired musician ears perceived
I maintain : both EQed HE-400i and EQed Sundara bass are dryer and tenser than EQed HE-4XX (a least in comparison to my unit), and sound cleaner.

I have no prejudice about Drop whatsoever.

You took the liberty to assert that HE-4XX is a better buy than Sundara, I took the liberty to express a different opinion, based on a comparative listening of models I actually own. Which as I stated is a subjective one (IMO used). But I agree with you about one point : out of the box, HE-4XX may be the best tuning of the three. Sundara are pretty good too, if you're not too much daring about some treble exposition. If not EQed, the lack of bass of the HE-400i is a no go. EQed, it's a completely different story.

The only one of the three I sometimes listen non EQed, is the Sundara for classical and acoustic DSD recordings.

 

[bobbooo]

I was talking about EQed comparisons

Then there's even less justification for your claims, if you're talking about them all EQed to the same target using Oratory's settings (I presume +7dB in the sub-bass for the Sundara to match the target). When the objective evidence does not support a sighted, uncontrolled, non-level matched subjective judgement, the most likely explanation is psychological, and there's no such evidence in the measurements to support your (amorphous) impressions of the Sundara and HE400i's being 'cleaner' than the HE4XX with 'dryer' and 'tenser' bass (whatever exactly that means).

I have no prejudice about Drop whatsoever.

Subconscious cognitive bias means exactly that. Any conscious perceived (lack) of biases have no bearing on the former, and in fact they can be in diametric opposition to each other.

 

[binka]

I made my own EQ which is a mix of Oratory and Amir's, Amir's in the upper mids and treble, Oratory in the lower mids and bass. I found Oratory's has too much energy in the treble and makes them sound harsh. It's very apparent in metal music with a lot of symbol and snare hits.

I often have this issue. What I did:

I just did -1dB on the 2250Hz shoutiness band. This keeps it perfectly in line with my preference version of harman at this location. Interestingly, it also brings it in closely in line with Amirs adjustment at this frequency. Then I just moved the -1 dB 10000Hz high shelf to 3500Hz. Solved. Just the right amount of treble energy for me, as most harman defaults (for me) need a little less at the 2-3kHz boost which he usually has a toggle at, but the other big issue is @ 4kHz, which can also really hurt, which he usually doesn't have a toggle at. The 3kHz high shelf tames it all just right, and results in the 6-7kHz reductions a little closer in line with Amir's reasoned adjustment, while keeping the overall treble shape really nice.

Alternatively, just move the -1dB high shelf to 2000Hz and leave the 2250Hz band. This all ends up looking like a more surgical version of Amir's treble, which I think is pretty solid effort given 2 bands.

 

[binka]

I have a couple technical questions that people may be able to answer.

The voltage requirement for 94dB, am I right in assuming that +-6dB requires a x2 or -x2 voltage? I use a Q5K, and can track my voltage, so I can therefore essentially figure out my peak listening volume accordingly? Is this the voltage needed for only what was measured at the FR peak, so probably around the 6-7kHz mark or so? Or is it averaged?

And if I listen with my peak volume at 94dB as determined via voltage (but EQed in such a way as this is only what the bass region is experiencing, tapering quickly through the rest), would I be getting something akin to, at worst, the 94dB distortion line? Or am I completely missing something here.

 

[solderdude]

I believe @amirm measures efficiency at 400Hz. Some manufacturers measure it at 500Hz or 1kHz and yet others may use (shaped) noise.

So at 400Hz the efficiency is 104dB/V but at 6kHz it is 109dB/V and at 2kHz = 101.5dB/V
At 10kHz Amir measures efficiency as 92dB/V where I measure 10kHz at 109dB/V.
This 17dB discrepancy is due to measurement errors caused by the pinna/ear canal and is the reason why efficiency is measured at frequencies where the pinna has little to no influence so around 400Hz to 500Hz.
At 1kHz there is a few dB influence already so can be used provided a correction is used.

And yes +6dB requires double the voltage.

 

[AdamG]

I have a couple technical questions that people may be able to answer.

The voltage requirement for 94dB, am I right in assuming that +-6dB requires a x2 or -x2 voltage? I use a Q5K, and can track my voltage, so I can therefore essentially figure out my peak listening volume accordingly? Is this the voltage needed for only what was measured at the FR peak, so probably around the 6-7kHz mark or so? Or is it averaged?

And if I listen with my peak volume at 94dB as determined via voltage (but EQed in such a way as this is only what the bass region is experiencing, tapering quickly through the rest), would I be getting something akin to, at worst, the 94dB distortion line? Or am I completely missing something here.

Welcome Aboard @binka.

 

[binka]

I believe @amirm measures efficiency at 400Hz. Some manufacturers measure it at 500Hz or 1kHz and yet others may use (shaped) noise.

So at 400Hz the efficiency is 104dB/V but at 6kHz it is 109dB/V and at 2kHz = 101.5dB/V
At 10kHz Amir measures efficiency as 92dB/V where I measure 10kHz at 109dB/V.
This 17dB discrepancy is due to measurement errors caused by the pinna/ear canal and is the reason why efficiency is measured at frequencies where the pinna has little to no influence so around 400Hz to 500Hz.
At 1kHz there is a few dB influence already so can be used provided a correction is used.

And yes +6dB requires double the voltage.

Appreciate this. Having read this I can now make sense of the audible distortion graph, and how to relate my voltage and EQ adjustments to approximate my listening levels.
@AdamG247 thank you kindly

 

[fluufy]

oratory1990 just updated his EQ for Sundara, previous is no longer available : https://www.dropbox.com/s/o3fza1a4kmmy4vr/Hifiman Sundara (2020 revised earpads).pdf?dl=0

Thank you for this - I did not know this had been updated. I have been using the previous eq (nearly), so I shall now experiment with the two.

 

[AntoniusRoses]

Anyone who's tried Amir's EQ on Roon and have terrible LF resonance/distortion? When I listened to Paula Cole's Tiger, her vocal in sync with the deep synthetic bass on 0:45 sounds broken with EQ on. I swapped to akg k371 with another set of EQ on(also Amir's), no issue, not as thunderous as Sundara but her vocals were super clean. I reduced the Q(not gain) value to 0.5 and the issue improved quite a bit, reducing gain also works but the LF tradeoff is significant.
Not sure what's going on. The graph shows well-controlled bass distortion but that's not what I hear after EQ.

 

[Jimbob54]

Anyone who's tried Amir's EQ on Roon and have terrible LF resonance/distortion? When I listened to Paula Cole's Tiger, her vocal in sync with the deep synthetic bass on 0:45 sounds broken with EQ on. I swapped to akg k371 with another set of EQ on(also Amir's), no issue, not as thunderous as Sundara but her vocals were super clean. I reduced the Q(not gain) value to 0.5 and the issue improved quite a bit, reducing gain also works but the LF tradeoff is significant.
Not sure what's going on. The graph shows well-controlled bass distortion but that's not what I hear after EQ.

Amp struggling maybe- Sundara far more challenging than the AKG?

 

[AntoniusRoses]

Amp struggling maybe- Sundara far more challenging than the AKG?

I'm using a30pro so amp shouldn't be an issue

 

[aldarrin]

Anyone who's tried Amir's EQ on Roon and have terrible LF resonance/distortion? When I listened to Paula Cole's Tiger, her vocal in sync with the deep synthetic bass on 0:45 sounds broken with EQ on. I swapped to akg k371 with another set of EQ on(also Amir's), no issue, not as thunderous as Sundara but her vocals were super clean. I reduced the Q(not gain) value to 0.5 and the issue improved quite a bit, reducing gain also works but the LF tradeoff is significant.
Not sure what's going on. The graph shows well-controlled bass distortion but that's not what I hear after EQ.

There's also the silent revision to the Sundara sometime in 2020; models produced before that had a different FR and will need a different EQ.

 

[AntoniusRoses]

There's also the silent revision to the Sundara sometime in 2020; models produced before that had a different FR and will need a different EQ.

I have the 2nd revision with improved pad, it may be individual unit difference or Amir didn't go through tracks with high amount of synthetic bass that bottoms out the driver.

 

[Ezees]

This is a review and detailed measurements of the Hifiman Sundara planar magnetic open back headphone. It was kindly sent to me by one of their retailers, Apos Audio and costs US $349.

The Sundara looks elegant and no less so than higher up in the line from Hifiman:

View attachment 124233

The cups don't swivel. That, and being new made for slightly uncomfortable feeling around my ears. The weight is inline with other headphones in this class at 390 grams. The cup is round and has inside diameter of 59 mm and depth of 18 mm.

The included cord is short and comes with right angle connector. It has a nice (silicon?) insulator. It did not seem microphonic to me.

Note: The measurements you are about to see are preformed using standardized GRAS 45CA headphone measurement fixture. Headphone measurements require more interpretation than speaker tests and have more of a requirement for subjective testing as a result. In addition, comparison of measurements between different people performing it using different configurations requires fair bit of skill. So don't look for matching results. Focus on high level picture. Listening tests are performed using RME ADI-2 DAC and its headphone output.

Mounting the headphone on the test fixture was super easy requiring no manipulation to get left and right to match at dual frequencies.

Hifiman Sundara Measurements
As usual, we start with our stereo frequency response measurements:
View attachment 124234

I like the near compliance with preference curve form upper bass to lower treble. The former though as you can see, droops as many headphones do. The peaks above 5 kHz also exceed our target which you can better see in a relative graph:

View attachment 124235

There is a bit of shortfall around 2 kHz as well which I tend to like! No, it is not good that way but it means that once I compensate for it, it should open the sound more.

Distortion shows little unexpected other than something going on between 6 and 7 kHz:

View attachment 124236

View attachment 124237

This is much better than Hifiman Ananda:

Group delay shows the typical messiness we see in mid-frequencies which seems to have a role in (good) spatial effects:

View attachment 124238

Impedance is flat at 40 ohm meaning you need current more than voltage to drive the Sundara:
View attachment 124241

Efficiency is slightly below average:

View attachment 124242

Hifiman Sundara Listening Tests
I had been listening to my AKG K371 for a few hours before swapping it with Sundara. The difference was startling in how open and expansive the sound became with Sundara. Alas, I quickly realized there is no sub-bass being produced. And sound signature was a bit bright and over exaggerated at the top. So out came the EQ tool:

View attachment 124244

Oh wow! The transformation was dramatic. Sub-bass came into play like nobody's business. Even at lower volumes I could feel the nice vibrations in my head! The notch filter took care of the highs being exaggerated and a bit harsh. And the fine but broad filter around 2.1 kHz helped the spatial qualities improve even more. Overall tonality now was warm with tons of detail especially in string instruments. Very lovely.

As a verification, I asked my son to come over and without looking at the measurements and EQ, listen to the headphone plain and then with EQ I had built above. After about half hour of listening he said there was no sub-bass and the there was something missing in the sound. With EQ he found the sound to be much improved causing him to say he likes it. So good correlation with my findings.

Conclusions
We have had a checkered history with Hifiman so far with HE-6 performing very well and the Ananda, not so much. It is nice to discover that Sundara, despite its much lower price than either two, brings a competent implementation to the table. Objectively we miss the bass by a mile but otherwise, compliance to our target is very good. Distortion while not best in class, is kept much more under control than Ananda. Likely the smaller driver is able to be much more optimized here.

Without EQ, I would not be a buyer as I love my deep bass response and highs that are a bit more sedated. With EQ, the Sundara transforms beautifully providing excellent spatial effect with respect to instrument and channel separation while providing the deep bass response that I crave.

I am happy to give a strong recommendation to Hifiman Sundara with equalization.

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

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I read your review of the Sundara. Glad you gave them a recommendation, they're good cans. However, most of Hifiman's headphones (and planars, generally) need time to burn in and loosen up from fresh out of the box. They recommend 150hrs (Ananda & Arya, can't remember about Sundara) but results can be heard after about ~20-50hrs. Pink noise and brown noise over a few nights works well. It's been my experience that the bass deepens, bass texture increases, treble sharpness and peaks smooth out, and soundstage widens and vocals/instruments becomes more layered. I currently own Ananda, Arya, 400i 2020, t50rp mk3. I used to own Sundara. Burn in has benefitted all of them, t50rp not as much. Would be glad to hear from those who've owned Sundara and Ananda for a few months.