This is a review, listening tests, EQ and detailed measurements of the HIFIMAN Susvara Planar Magnetic Headphone. It was kindly drop shipped by a member and costs US $6,000.
Owner was advised that the Benchmark AHB2 power amplifier would be the right device to power it so I tested it with that as well as my normal Topping A90 headphone amplifier.
Hifiman aces the design of the Susvara coming in a modern and elegant looking package. It is rather lightweight for its size as well, making it comfortable to wear. The only minor issue there was feeling the strap on my head but otherwise, it was excellent and I almost forgot I was wearing it. You can't see it but the metal strap is rectangular which I am not fond of in general but it kind works here. Whether you are getting $6,000 worth of luxury here I don't know but a good effort has been made to make you feel you are getting a flagship headphone.
If you are new to my headphone measurements, I highly recommend that you watch my video tutorial on headphone measurements which ironically uses Hifiman HE-6 as an example.
Hifiman Susvara Headphone Measurements
Let's start with frequency response of the Susvara and compare it against our desired target:
I was very surprised by the highly variable nature of the measurements. It is beyond noisy. Other measurements that use high level of smoothing don't show this as much and with it, hide potential issues there. That aside, we lack bass which is typical of a number of other headphones. Response is also insufficient in the 1 to 3 kHz which likely is there to keep the headphone form sounding too bright (given the lack of bass). Developing eq to correct the high frequency response is going to be a bit challenging but we will try using the deviation for our target response:
I was disappointed to see high levels of distortion where our hearing is most sensitive:
Narrow spikes usually indicate resonances so they are audible beyond their distortion characteristics and point to design issues. We can also see how fast they escalate. 94 to 104 dBSPL causes a 3 3X or so increase but go to 114 dBSPL and they shoot through the roof. What's more, if you go just 1 dB beyond, the drivers bottom out and just buzz! Wanting to rule out Topping A90's own distortion I switched to Benchmark AHB2. Alas, I was not able to get above 113 dBSPL as AHB2 ran out of voltage drive. Taking this into account, we see that the problem is the headphone and not the amps:
To make a more level matched comparison, I tested again but at 104 dBSPL:
Ignoring minor deviations, we see that the response is identical so there is really no need for the Benchmark AHB2 in this application. The Topping A90 is actually more capable of driving the Susvara. As noted, this is due to AHB2 not having enough voltage drive due to rather "high" impedance so SUSVARA (as compared to a speaker):
The Susvara is very insensitive so you definitely need a very capable amplifier to drive it:
Back to our distortion, here it is in absolute levels:
Even at 94 dBSPL we are exceeding our target between 4 and 5 kHz. I searched and there is at least one other measurement on the web that shows a similar issue so please don't say this sample must be broken. There is clearly a design issue here. The super messy Group Delay points to multiple sound sources (i.e. resonances):
I don't think I have ever seen such broad messiness across almost the entire audible band above bass.
Let's agree that objectively we are not doing well here. But "how does it sound?"
Hifiman Susvara Listening Tests and Equalization
I was listening to music on my everyday headphone and decided to just switch to Susvara without going back to my reference test clips. First thing I noticed -- which was odd -- was the high frequencies being distorted. When I went back to my standard tracks, this did not stand out. There, the tonality was "OK" but nothing exciting for me. So out came the EQ tools to correct the frequency response errors:
Ignore Band 5 for now. Addition of the two filters at 1900 and 4500 Hz filled in the treble area but now the headphone was bright. So I added a pair of filters to boost the bass region with similar slop to the inverse of Susvara frequency response. Once there, overall response was far better with good bit of bass and much improved spatial qualities. Alas, I was still sensing brightness. I pulled down the response at 4500 Hz and that helped but it was still bright. So I broke my usual rule of not messing with > 8 kHz and dialed in a negative notch filter at 12.7 kHz. That tailored the tonality to what I liked.
I sat back and started to enjoy the fidelity which was at times quite excellent. That was at low and medium levels. With my dynamic tracks I crank up the volume and I was quite surprised when I started to hear static when I did not even have it super loud. Suspecting EQ being the problem, I defeatured the whole thing and problem remained (although required a bit more volume to get there). This is a showstopper in my book as the problem is not even the elevated bass with EQ where the problem usually occurs. I think the issue is the high frequency issues we have found.
I know some will claim to not hear this or complain that the above level is too loud. I have my standards of how much power a headphone needs to be able to handle and the Susvara falls way short of that. I want perfection at this price point yet even if this was a $400 headphone, I would complain about this problem.
Conclusions
Hifiman nails the look and overall industrial design of the Susvara delivering a headphone that puts a smile on my face every time I look at it. It is also very comfortable to wear. Alas, objective measurements show issues across the board. Response is quite variable beyond typical noise. Has deficiencies against our target. And importantly, appears to have serious resonance issues that manifest themselves in distortion graphs. Listening tests confirm those distortion finding with the headphone creating static at levels that should not remotely be possible with a flagship headphone.
If you don't exceed medium loud levels distortion would not impact you. And maybe you are OK with this type of tuning. Neither is my cup of tea, leaving me with the sadness that such a great looking headphone is saddled with serious technical problems.
I can't recommend the Hifiman Susvara headphone. I also don't recommend pairing it with Benchmark AHB2. Even though it can almost drive it, it costs a lot more than a capable headphone amplifier.
P.S. I know some are going to be upset with the findings in this review. I highly recommend you watch my video tutorial on headphone testing before commenting.
------------
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/
Owner was advised that the Benchmark AHB2 power amplifier would be the right device to power it so I tested it with that as well as my normal Topping A90 headphone amplifier.
Hifiman aces the design of the Susvara coming in a modern and elegant looking package. It is rather lightweight for its size as well, making it comfortable to wear. The only minor issue there was feeling the strap on my head but otherwise, it was excellent and I almost forgot I was wearing it. You can't see it but the metal strap is rectangular which I am not fond of in general but it kind works here. Whether you are getting $6,000 worth of luxury here I don't know but a good effort has been made to make you feel you are getting a flagship headphone.
If you are new to my headphone measurements, I highly recommend that you watch my video tutorial on headphone measurements which ironically uses Hifiman HE-6 as an example.
Hifiman Susvara Headphone Measurements
Let's start with frequency response of the Susvara and compare it against our desired target:
I was very surprised by the highly variable nature of the measurements. It is beyond noisy. Other measurements that use high level of smoothing don't show this as much and with it, hide potential issues there. That aside, we lack bass which is typical of a number of other headphones. Response is also insufficient in the 1 to 3 kHz which likely is there to keep the headphone form sounding too bright (given the lack of bass). Developing eq to correct the high frequency response is going to be a bit challenging but we will try using the deviation for our target response:
I was disappointed to see high levels of distortion where our hearing is most sensitive:
Narrow spikes usually indicate resonances so they are audible beyond their distortion characteristics and point to design issues. We can also see how fast they escalate. 94 to 104 dBSPL causes a 3 3X or so increase but go to 114 dBSPL and they shoot through the roof. What's more, if you go just 1 dB beyond, the drivers bottom out and just buzz! Wanting to rule out Topping A90's own distortion I switched to Benchmark AHB2. Alas, I was not able to get above 113 dBSPL as AHB2 ran out of voltage drive. Taking this into account, we see that the problem is the headphone and not the amps:
To make a more level matched comparison, I tested again but at 104 dBSPL:
Ignoring minor deviations, we see that the response is identical so there is really no need for the Benchmark AHB2 in this application. The Topping A90 is actually more capable of driving the Susvara. As noted, this is due to AHB2 not having enough voltage drive due to rather "high" impedance so SUSVARA (as compared to a speaker):
The Susvara is very insensitive so you definitely need a very capable amplifier to drive it:
Back to our distortion, here it is in absolute levels:
Even at 94 dBSPL we are exceeding our target between 4 and 5 kHz. I searched and there is at least one other measurement on the web that shows a similar issue so please don't say this sample must be broken. There is clearly a design issue here. The super messy Group Delay points to multiple sound sources (i.e. resonances):
I don't think I have ever seen such broad messiness across almost the entire audible band above bass.
Let's agree that objectively we are not doing well here. But "how does it sound?"
Hifiman Susvara Listening Tests and Equalization
I was listening to music on my everyday headphone and decided to just switch to Susvara without going back to my reference test clips. First thing I noticed -- which was odd -- was the high frequencies being distorted. When I went back to my standard tracks, this did not stand out. There, the tonality was "OK" but nothing exciting for me. So out came the EQ tools to correct the frequency response errors:
Ignore Band 5 for now. Addition of the two filters at 1900 and 4500 Hz filled in the treble area but now the headphone was bright. So I added a pair of filters to boost the bass region with similar slop to the inverse of Susvara frequency response. Once there, overall response was far better with good bit of bass and much improved spatial qualities. Alas, I was still sensing brightness. I pulled down the response at 4500 Hz and that helped but it was still bright. So I broke my usual rule of not messing with > 8 kHz and dialed in a negative notch filter at 12.7 kHz. That tailored the tonality to what I liked.
I sat back and started to enjoy the fidelity which was at times quite excellent. That was at low and medium levels. With my dynamic tracks I crank up the volume and I was quite surprised when I started to hear static when I did not even have it super loud. Suspecting EQ being the problem, I defeatured the whole thing and problem remained (although required a bit more volume to get there). This is a showstopper in my book as the problem is not even the elevated bass with EQ where the problem usually occurs. I think the issue is the high frequency issues we have found.
I know some will claim to not hear this or complain that the above level is too loud. I have my standards of how much power a headphone needs to be able to handle and the Susvara falls way short of that. I want perfection at this price point yet even if this was a $400 headphone, I would complain about this problem.
Conclusions
Hifiman nails the look and overall industrial design of the Susvara delivering a headphone that puts a smile on my face every time I look at it. It is also very comfortable to wear. Alas, objective measurements show issues across the board. Response is quite variable beyond typical noise. Has deficiencies against our target. And importantly, appears to have serious resonance issues that manifest themselves in distortion graphs. Listening tests confirm those distortion finding with the headphone creating static at levels that should not remotely be possible with a flagship headphone.
If you don't exceed medium loud levels distortion would not impact you. And maybe you are OK with this type of tuning. Neither is my cup of tea, leaving me with the sadness that such a great looking headphone is saddled with serious technical problems.
I can't recommend the Hifiman Susvara headphone. I also don't recommend pairing it with Benchmark AHB2. Even though it can almost drive it, it costs a lot more than a capable headphone amplifier.
P.S. I know some are going to be upset with the findings in this review. I highly recommend you watch my video tutorial on headphone testing before commenting.
------------
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/
