Low distortion headphone for use with EQ

[Lbstyling]

Hello all,

I have been getting into headphones thanks to this forum recently and am now looking into purchasing low distortion headphones.

Why distortion and not FR?
I like many have EQ available to tune a headphone to the Harman curve using either Amir or Oratory's settings, and would always use it. My own experience with DIY speakers lead me to the conclusion that low distortion at high SPL is the way to go there (I'm sure many will disagree, this is absolutely fine, but outside of the scope of this thread to start down)

So, I have spent some time with EQ and a set of Superlux HD681 phones with velour pads (thanks to Solderdude, and Oratory's EQ profile having a setting for velour pads!). The purpose was to get a grounding in what I like before spending significant money.
My preference is for more than Harman Curve bass levels, so I might be driving the chosen phones quite hard to get the bass up at high SPLs, other than that, the Harman 2018 curve is about right by my ear.
At the moment, I am also assuming somthing is lost when going over to closed headphones over open due to the reflections of the back-wave off the casing. Happy to be told I'm wrong, but as I have no specific need for closed headphones, I assume open would be better.

My ears are quite small, my hair is notably 'fine' and is cut short. Seal has not been an issue for me this far.

At the moment, top performing options I have found are the following:

Dan Clarke AEON RT: $500.00. Low distortion across the audio band (particularly low in the bass, extra points for doing this with above Harman target bass levels). Downside closed and not sure if they are angled drivers?
https://www.audiosciencereview.com/...-audio-aeon-rt-review-closed-headphone.19393/

Dan Clarke AEON open X. $500.00. not sure if they are angled drivers? I have not found any distortion data for these yet. I can only hope they are basically the AEON RT just with the back removed and hence possibly similar distortion levels..?
https://drop.com/buy/drop-dan-clark-audio-aeon-open-x

Audeze LCD-2F (Fazor): £749.00 0.2% in the mids and bass. 0.1% in the treble, Impressive. Considerable money. Not sure what this would offer over the Sundara unless it can handle more bass EQ without distorting.
https://diyaudioheaven.wordpress.com/headphones/measurements/audeze/lcd-2-fazor/

HIfiman Ananda: £504.32 Low distortion across the audio band (averaging 0.25%, peaking to 0.5%) and like the Dan Clarke Aeon RT, has low distortion in the bass range, but it appears that Dan Clarke has generally lower distortion levels over all. Some reports suggesting they distort when turned up loud compared to alternatives. Are they angled drivers?
https://diyaudioheaven.wordpress.com/headphones/measurements/hifiman/ananda/

Hifiman Sundara £300.00. In many respects, this should be the winner. The current version is reported to have outstanding tracking of the Harman curve (see link), however, it shows a significant peak in 2nd harmonic distortion at 11khz. Does this matter being that you hear it at 22khz, and I'm only good out to 16.5khz with my hearing? probably not. How loud do they get? Do they distort if you EQ the bass up? Angled drivers (pad revision)
(see post 4 here: https://www.audiosciencereview.com/forum/index.php?threads/hifiman-sundara-vs-ananda.16627/
https://diyaudioheaven.wordpress.com/headphones/measurements/hifiman/sundara/

Sennheiser HD650 £300.00. Very low distortion except for the bass which is probably to high for the headphone to be considered when the lower bass requires so much EQ to get to my preferred levels.. Do not have angled drivers. Bass distortion can be lowered a tad by dampening resonances in the headphone with Dynamat.
https://www.audiosciencereview.com/forum/index.php?threads/sennheiser-hd650-review-headphone.18774/
How to lower distortion for this headphone: https://www.superbestaudiofriends.o...d650-dynamat-mods-proof-that-its-not-bs.2098/


So the first questions are:
1) How well does the Sundara take to high SPL and the bass EQ'ed up to above the Harman target?
2) Is the Ananda significantly more capable of being driven from a phone to good SPLs than the Sundara?
3) Does anyone have any information on the Dan Clarke AEON open X distortion levels?
4) Unless the answer to 1 is 'not well as it cannot handle much EQ' I'm not sure what the real value of the Ananda is over the Sundara. Am I missing somthing?

Any other advice is welcome!

 

[SeaNNyT]

Any measurements for the Auteur out there?

 

[Maes Hughes]

I can address a few issues partly. In general, the closer the natural FR is to your preferred target for headphones the easier it will be to get a satisfactory result with eq(assuming distortion is within the non audible relm). Depending on your experience adding bass shelves and peak nulling are some of the easier techniques to perform with satisfactory results.

In regards to bass eq differences between sundara, ananda, and lcd-2 the difference was only in the lowest of bass frequencies. In my experience, the biggest issues were fitment and positional variation. Sundara reacted the most audibly with bad seal and I could only get a bad seal with my head size and shape. Ananda was performed better in the bass with seal loss and was closer to my ideal target(completely subjective on your preference), but I had much more issue with positional variation impacting my perception of the sound. The LCD-2 had the least amount of lowest fr bass shift with seal break almost to the point where it was inaudible. I also had little to no problems always getting a good fit. The Dan Clark items for me were unable to be evaluated properly due to fitment.

Tldr; a general recommendation to take pad measurements(actual physical dimensions in relation to your head/ear size) and fit into consideration along with distortion as no amount of eq can compensate for complete frequency loss due to seal performance.

 

[outerspace]

There is two 50 Hz tones in attached file. One clean, another with 5% THD. It's pure tones, worst case scenario, in music it's even less audible (also you can test yourself with different THD levels here). So I doubt low frequency distortions of HD650 would be a problem on normal sound levels on real music.

 

[Lbstyling]

There is two 50 Hz tones in attached file. One clean, another with 5% THD. It's pure tones, worst case scenario, in music it's even less audible (also you can test yourself with different THD levels here). So I doubt low frequency distortions of HD650 would be a problem on normal sound levels on real music.

I appreciate the link, and I don't think it's flawed, but rather limited in scope when dealing with sub bass soecifically. The test simulates a level of THD, but not the cause, or dynamic conditions. Coil rub (for instance) can show up as 0.05% yet is audible under blind test conditions. IMD is a better indicator of audibility, but is not an available measurement. Also, the choice of 50hz means 3rd harmonic is at 150hz, whereas if we tested 150hz, the ear is much more sensitive to the 3rd harmonic of 450hz. Also, we must remember that when using a single full range driver, we are playing 20hz and 20khz at the same time from the same driver, so the LE X becomes very important when bass is nearing Xmax of the driver, along with what the Xmax VS xmech are.

I'm not certain what the limiting factors are when using planar drivers, but assume the distance between the mylar and magnets touching would be one. At least they are not electrostatic like my old Quad ESL63s! You would get a little hole every time the mylar touches the stator!

Of course having low THD does not guarantee zero problems either, but if it does not have significantly raising distortion at 20hz, we are at least less likely to be loosing control of the diaphragm at somewhat higher levels unless we hit somthing. In dynamic drivers, 5% THD from a driver is often only 3db gain increase away from 50%+ or even 100% as the coil is leaving the gap.

 

[outerspace]

The test simulates a level of THD, but not the cause, or dynamic conditions. Coil rub (for instance) can show up as 0.05% yet is audible under blind test conditions.

I doubt there is a coil rub at safe volume levels. You need about +5..+7 dB on 40 Hz to get adequate level of bass. No need to go deep to 20 Hz to get good result. AFAIR Sean Olive said good bass response up to only 50 Hz is correlate with sound quality. I have tested this and I don't need go deeper than 40 Hz even with bassiest examples of my music (one of the attached files have sharp 40Hz low-shelf filter, check difference yourself)

IMD is a better indicator of audibility, but is not an available measurement.

Researches shows that IM distortions are very poor benchmark in case of headphones.

Also, the choice of 50hz means 3rd harmonic is at 150hz, whereas if we tested 150hz, the ear is much more sensitive to the 3rd harmonic of 450hz.

HD650 have -60 dB of 3rd harmonic for 50 Hz (at 150 Hz). I very doubt it's audible, especially on real music signal.

You can experiment with distortions by this app.

 

[Lbstyling]

]
[QUOTE="outerspace, post: 678554, member: 190 I doubt there is a coil rub at safe volume levels. You need about +5..+7 dB on 40 Hz to get adequate level of bass. No need to go deep to 20 Hz to get good result. AFAIR Sean Olive said good bass response up to only 50 Hz is correlate with sound quality. I have tested this and I don't need go deeper than 40 Hz even with bassiest examples of my music (one of the attached files have sharp 40Hz low-shelf filter, check difference yourself)


Researches shows that IM distortions are very poor benchmark in case of headphones.


HD650 have -60 dB of 3rd harmonic for 50 Hz (at 150 Hz). I very doubt it's audible, especially on real music signal.

You can experiment with distortions by this app.[/QUOTE]

Thanks for this.
The difference in our positions is just reasonable case Vs worst case IMO. I appreciate your points, but I wish to cover a worst case scenario.

For instance, if I prefer +7db or more of bass over the Harman curve, and will play back at occasional 115db+ peaks for a song or so, your example of -60db 3rd harmonic is not likely to represent the situation for me (for instance), especially if looking for 3db headroom.

 

[outerspace]

For instance, if I prefer +7db or more of bass over the Harman curve, and will play back at occasional 115db+ peaks for a song or so

Be very careful about this. Most of tracks have about -10 dB of average loudness below the peaks. So 115 dB SPL at peaks mean at least 100 dB SPL of average loudness. You can damage your hearing after only 15 min of such exposure. It's not what you became suddenly deaf, you may not even notice it until made hearing test.