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Author Topic: HE400 vs. HE500 Non-Linear Distortion and Correlation with Bass Quality.  (Read 9554 times)

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Marvey

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Thanks to LFF for loaning me his HE500. I've long been curious to see these distortion measurements against each other. A few people have commented at how the HE500 bass is a little bit muddy or atonal. Not annoyingly so, but just a little bit. I know it didn't bother RD or me, but we also felt it was definitely there.

I actually own the HE400, and have always felt that the HE400, despite its much lower price, had better quality bass than the HE500. Having made a substantial effort to demonstrate to yet another one of those know-it-all-noobs on HF: (http://www.head-fi.org/t/595683/fostex-th900-impressions-discussion-thread/1350#post_8550368) the correlation between distortion and bass quality, it would indeed be embarrassing to me if the harmonic distortion measurements didn't pan out in this case. Whew! Good thing that they did. (I really wasn't that concerned as I've been taking similar types of measurements on speaker drivers years ago.)

The first set of two are the HE500 measurements (channels don't match well, but I ran the measurements twice to confirm they are legit). The second set are the HE400 measurements. In REGARDS TO THE BASS (< 70Hz): While 2nd order harmonic distortion remains the same, we see much more 3rd order distortion (orange line) on the HE500. 3rd order distortion actually hits 0.1% by 70Hz on the HE500. Whereas for the HE400, 3rd order distortion remains visibly lower and consistent between 0.02% to 0.06%.

The HE500 does seem to fare better throughout the rest of the spectrum however. The HE400 seems to choke in the lower mids.
« Last Edit: July 23, 2012, 06:13:45 AM by purrin »
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Sforza

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So I reckon we should take these measurements are further supportive evidence that higher distortion, even if it's 3rd order, would have a detrimental effect?

Hmm. I was previously working with the assumption that anything below .5 would be subjectively insignificant, so I guess I ought to consider revising my opinion on the topic :-Z It'd be nice to have more objective basis for the bass quality though. Thanks for taking the time to make these.
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frenchbat

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Purrin, do you see any noticeable difference between the grills of both units ? Some believe there was a change during production that yields lower resonance on the HE500. Maybe there's a link there.

Nice measurements by the way. I'm getting to know my headphones better and better thanks to you.
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Marvey

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I don't see a difference in the grills of these two units.

Whatever order the distortion, as long as it's high enough, is detrimental. Some feel that odd order distortion (3rd) sounds worse than even order (2nd). There's an old argument that SE tube amps which have artificially high 2nd order distortion are euphonic. Personally I think this is BS, and any kind of distortion at a high enough level sounds bad.

People think of distortion as crackling, fuzziness, etc. But that's gross distortion. Lower levels of distortion can still be audible and translate into more subtle effects such as lack of clarity or a dirtiness with the sound-floor (a grey instead of a black background so to speak.)

Bass distortion is easily heard as muddiness, thickness, indistinctness with tone, etc. or worse!
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frenchbat

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Thanks for checking the grills Purrin. Much appreciated.
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jerg

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Yeah, the HE400s grills are also made of steel, I thought they were plastic but after doing the grill mods (linked in the HE400 velour thread here), I realized that it's metallic underneath the black paint. The issue with mids/highs distortion with HE400 is entirely driver-related, as everything else is identical to the construction of the HE500s.
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Marvey

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I think it was discussed somewhere else on this site that the distortion was because of its very coarse trace pattern on the diaphragm. The fact that the HE400 even makes noise, much less sounds good, is a wonder.

I'm not sure that the mid distortion is even really that audible or more precisely objectionable. THD (not pictured but probably something close to the D2 line) is probably not that much higher than 1%. However during a direct comparison, the HE500 did sound more refined, crisper, and more detailed in the mids than the HE400.
« Last Edit: July 23, 2012, 07:52:20 PM by purrin »
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Aravind

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just for comparison, can u post the NLD graphs for lcd2/3...to see if they correlate with their famed low frequency reproduction...
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rhythmdevils

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The HE500 bass sounded kind of like underdamped ortho bass to me esp considering the driver size, which should put out ze crazy man bass.  And since it has no damping, and the pads aren't sealed, I'm guessing the driver is a bit out of control. 

The HE500 has a very weird bass effect I've never noticed in any other headphone.  When you take them off and they're a few inches from your ears (headphones removed with a few inches of space from ears) the bass volume actually increases significantly and looses all definition or detail, and you get this intense flabby sub effect.   I'm guessing this is a symptom of whatever is going on with the HE500 bass.  They break a lot of conventional ortho rules with the HE500 -no pad seal, no damping, not to mention what others have mentioned about the diaphragm and traces design.  FWIK, an "air damped" ortho like this is actually ideal but I'm skeptical the HE500 is making it work in an ideal way.  If that makes sense...
« Last Edit: July 23, 2012, 08:05:02 PM by rhythmdevils »
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Marvey

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If I have time, I will try the same measurement without a seal or placed a cm away from the coupler. Should be interesting.
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