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Sennheiser HD650 Review (Headphone)

Feelas

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I hear that broad hill around 200 hz as fat/warm/bloat. I've got my eq set up to reduce the output in that area. I haven't attempted anyone else's eq, I'm happy with mine. I pull up the deep bass, but reduce the upper bass. Works for me with the Drop 6XX. Nothing I've done can really fix the HD 599, it sounds thick and veiled no matter what I do.
Do you feel that ~2dB hill (that is a broad one and I must say that it looks innocent, but 2dB is A LOT) the same way as HD599 thickness, or is the character different?
 

Robin L

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I think it might be the THD, since on K371 there's a massive bass shelf and yet there's no real bloat.
I see nothing in this measurement to suggest that any particular region of the bass is displacing any other. It's a very smooth and continuous lift from 3khz down to 30hz:

fr-stock.png
 
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Feelas

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I see nothing in this measurement to suggest that any particular region of the bass is displacing any other. It's a very smooth and continuous lift from 3khz down to 30hz: View attachment 107634
I think @solderdude uses bass compensation on graphs. Obviously, nothing to be afraid of - the 4dB bass increase is said to be needed for proper bass compensation over lack of physical bass feeling, I myself also agree with this.

Not to say that I feel K371's are dark in balance, just that they're not bright and yet not leaky or boomy at all. They're especially bassy when set in line with typical pairs having either a lack of sub-bass (closed cans) or a roll-off, the difference hits 15dB for some opens. I've been tweaking my (terrible) Mackies CR4X-BT (don't ask, I'm really budgeting) for two months and cannot feel any boxiness I had with misaligned upper bass/lower midrange.

Also, I don't feel QC35 II boomy nor veiled w/ bass, even when their tonal balance is clearly with roll-off. Both QC35 II and K371 have great THD in bass range.
 

Robin L

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Do you feel that ~2dB hill (that is a broad one and I must say that it looks innocent, but 2dB is A LOT) the same way as HD599 thickness, or is the character different?
I'm not sure of the cause. My subjective impression is very strong, but I am not in a position to make a technical judgement. The 6XX sounds detailed and open most everywhere save the high treble, where my impression is that it gets soft in the region where violins are supposed to have some 'rosin on the bow'. My impression is the the K371 isn't quite as open and clear overall, but has an advantage in that area where the sound of fiddles can get rough and are supposed to sound a little rough. The bass impact of the K371 is higher without eq than that of the 6XX/HD 650.
 

Feelas

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I'm not sure of the cause. My subjective impression is very strong, but I am not in a position to make a technical judgement. The 6XX sounds detailed and open most everywhere save the high treble, where my impression is that it gets soft in the region where violins are supposed to have some 'rosin on the bow'. My impression is the the K371 isn't quite as open and clear overall, but has an advantage in that area where the sound of fiddles can get rough and are supposed to sound a little rough. The bass impact of the K371 is higher without eq than that of the 6XX/HD 650.
Are 6XX/650s detailed on reverb tails and discriminant on recording spaces or not?
 

Robin L

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Are 6XX/650s detailed on reverb tails and discriminant on recording spaces or not?
Not in the same way as the AKG K371s. EQ makes the 6xxs sound more open [to these ears], but the character of the sound is different. When listening to the K371s, John Martyn's "Solid Air" come to mind, there is a sense of real texture to plate echo and such with the closed-back AKG 'phones, more of a sense of openness with the Sennheiser 'phones.
 

Feelas

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Not in the same way as the AKG K371s. EQ makes the 6xxs sound more open [to these ears], but the character of the sound is different. When listening to the K371s, John Martyn's "Solid Air" come to mind, there is a sense of real texture to plate echo and such with the closed-back AKG 'phones, more of a sense of openness with the Sennheiser 'phones.
And here I'm blatantly unable to cite any real scientific papers, so let's speculate. If I'm correct, it's recommended that recording and playback spaces have flat RT30/RT60 (reverb dropoff by -30 and -60 iirc).

Then, K371s, due to proper midrange & bass smoothness and lack of roll-off let the plate echo happen, low THD in bass & mids don't obscure the -30 thru -60 tails in that range. Yet, they somehow lack the proper treble (I'd say, 6-20k) HRTF fit and some smoothness.

The 6-20k are well-done on HD6xx range and thus the open sound is happening due to proper reverb structure & evenness (keep in mind that we're talking -30 to -60dB) of response. Does thay make sense? I'm just looking for the source; right now I feel that % THD is really useless, since we're always dealing with miniscule details and one-two dB difference might cause the reverb to be unnatural easily. That shows how flawed the whole measurement process is due to lack of ability to make real treble measurements. Happily, we can assess smoothness of lower ranges.

Simply, overall smoothness & THD highlight different parts of reverberance, thus ending up in different soundstaging.

The overall consistency of reverb & lack of spatial cues - mostly reverb - masking could paint the full soundstaging image in the FR domain, abstracted away from other factors. Layering must be gone when the reverberation in any range overthrows the harmonics of instruments that engineer wanted to show up close.
 
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Robbo99999

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You folks are discussing excess response in the 200Hz area - this will make it sound muddy. A lot of headphones have too much response in this area, the Headphone Harman Curve often addresses this by having a low Q (broad) negative gain peak filter at this point. I really hate too much response in the 200Hz area, sucks detail from the whole frequency spectrum.
 
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I hear that broad hill around 200 hz as fat/warm/bloat. I've got my eq set up to reduce the output in that area. I haven't attempted anyone else's eq, I'm happy with mine. I pull up the deep bass, but reduce the upper bass. Works for me with the Drop 6XX. Nothing I've done can really fix the HD 599, it sounds thick and veiled no matter what I do.
I got pretty much the same results when matching the 650 to the harman target. Not that there was a bloat to begin with, but that elevated area from 200 to 500, I think it contributes to the infamous sennheiser veil along with the slightly reduced highs. After eq, that "veil" disappeared from my ears regardless the elevated bass and tipped the scale towards the 650 instead the 600.
 

infinitesymphony

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Other things to keep in mind when discussing this mid-bass range of the HD650s that Amir mentioned back in the review. In addition to a relative bump centered around 200 Hz, we also have...

A group delay issue at around 250 Hz:



A resonance at around 290 Hz:



Both could affect the perception of distortion and decrease subjective quality / "solidity" in that range.
 

Pmelb

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EQ'ing HD650/6XX headphones (and other brands/models) to a Harman target using say Equalizer APO can be a bit hit and miss, as others have noted the measurement rig setup, condition of pads, placement of headphones on the test rigs etc. all contribute to minor differences in frequency response, and hence when using these 'auto EQ' options you are not getting the best outcome for your particular headphones.

It is both an art and science to do EQ, use the settings provided by others as a base and tweak to suit your preference. Nothing is set in stone when it comes to EQ.

For my Senns my EQ settings are very similar to Amir's and this for me also improves then nicely for my taste. These headphones really are a gateway drug into the audiophile world!
 

greyscale

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EQ'ing HD650/6XX headphones (and other brands/models) to a Harman target using say Equalizer APO can be a bit hit and miss, as others have noted the measurement rig setup, condition of pads, placement of headphones on the test rigs etc. all contribute to minor differences in frequency response, and hence when using these 'auto EQ' options you are not getting the best outcome for your particular headphones.

It is both an art and science to do EQ, use the settings provided by others as a base and tweak to suit your preference. Nothing is set in stone when it comes to EQ.

For my Senns my EQ settings are very similar to Amir's and this for me also improves then nicely for my taste. These headphones really are a gateway drug into the audiophile world!
Pmelb, Are you running Roon?
 

Pmelb

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Pmelb, Are you running Roon?
I don't use Roon. I typically use Tidal with Equalizer APO / Peace.

For each of my headphones I get its measured frequency response png image from the AutoEQ GitHub repo, then referencing their image which shows the raw measured against the target I then manually adjust to my taste. This way I'm not just blindly accepting EQ settings, but instead am tweaking to my particular headphones and achieve / retain the sound character of the headphones that I prefer.
 
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Solderdude measured the 660s and compared to 600 & 650:
HD660S | DIY-Audio-Heaven (wordpress.com)
Thank you for the link. It seems that this measurement confirms that HD600 has the most neutral response as many people has reported. HD600 has the lowest distortion below 100Hz except 2nd harmonics which we hardly hear even at 10%. 3rd+ harmonics make the bass sound muddy. 660S would be the best choice for who does not listen to bass heavy music due to lower distortion above 100Hz.

It's interesting to see that Sennheiser still can't design a headphone which obviously better than HD600.
 
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Robbo99999

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Thank you for the link. It seems that this measurement confirms that HD600 has the most neutral response as many people has reported. HD600 has the lowest distortion below 100Hz except 2nd harmonics which we hardly hear even at 10%. 3rd+ harmonics make the bass sound muddy. 660S would be the best choice for who does not listen to bass heavy music due to lower distortion above 100Hz.

It's interesting to see that Sennheiser still can't design a headphone which obviously better than HD600.
You mean HD600 has the lowest distortion above 100Hz, because the HD600 is very clean everywhere except in the bass in terms of distortion - last time I checked solderdude's measurements & compared HD600 & HD650. HD650 is a bit cleaner in the bass than HD600, but less clean everywhere else in comparison to HD600.
 
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You mean HD600 has the lowest distortion above 100Hz, because the HD600 is very clean everywhere except in the bass in terms of distortion - last time I checked solderdude's measurements & compared HD600 & HD650. HD650 is a bit cleaner in the bass than HD600, but less clean everywhere else in comparison to HD600.
No. I'm talking about third and higher harmonics. We can ignore 2nd harmonics, which is octave up, and we can't hear it.
 

Robbo99999

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No. I'm talking about third and higher harmonics. We can ignore 2nd harmonics, which is octave up, and we can't hear it.
I see, I can't comment on the specifics of that, don't know enough about the significance of the different harmonics.
 
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I see, I can't comment on the specifics of that, don't know enough about the significance of the different harmonics.
There are many researches about audibility of harmonics, and many studies concluded that human can't hear 10% of 2nd harmonics. 3rd and higher harmonics are audible even at very low level. Worst harmonics are 5th and higher, which should be eliminated as much as possible.
 

Robbo99999

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There are many researches about audibility of harmonics, and many studies concluded that human can't hear 10% of 2nd harmonics. 3rd and higher harmonics are audible even at very low level. Worst harmonics are 5th and higher, which should be eliminated as much as possible.
Fair enough, it's one of my knowledge gaps, I'll have to read up on it if I want to fill it.
 
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