[Sigmaaa]

https://soundnews.ro/2017/12/25/sennheiser-hd660-s-the-legend-continues/

 

[DarKu]

https://soundnews.ro/2017/12/25/sennheiser-hd660-s-the-legend-continues/

Hey guys, hope you like it.
It took a little bit more than expected due to my cold, but my hearing is now again at full potential so I finished it.
I posted it on head-fi as well: https://www.head-fi.org/showcase/sennheiser-hd660s.22727/reviews

 

[sabocat]

Hey guys, hope you like it.
It took a little bit more than expected due to my cold, but my hearing is now again at full potential so I finished it.
I posted it on head-fi as well: https://www.head-fi.org/showcase/sennheiser-hd660s.22727/reviews

Thanks for taking the time to write this review. Is it just me or is anyone else left scratching their head after reading the inner fidelity review which purports to hear grain in the 660s?

 

[Rob80b]

Well as I sit here patiently waiting (the boat must be half way across the Atlantic) on my 660s the somewhat opposing reviews make its forth-coming arrival all the more entertaining.
Unlike with the 700s….I do not see the reviews so much as polarizing as the positive reviews do see the 660s as a definite technical advancement on the long in tooth and aging 600/650s…. but the less than open or negative reviews all seem to be “grasping for straws” as Sennheiser has indeed slightly changed the signature sound of their much beloved choice in headphones and it may actually be put on the chopping block. (eventually) This is not to say the 600/650s are now redundant (there are thousands of them out there), any headphone that can maintain a current status after 20 years observably needs to be given credit for sustainability and they do continue to offer a more palatable, less challenging pedestrian serving. (for many not a bad thing)
Just an educated guess but from what I’ve picked up on so far I’d say I fall into the 660s camp as they appear to offer that little bit extra I always found lacking in all the previous offerings…but I’ve yet to actually hear them so any of my comments are actually moot. : (

Oh...and A Merry Christmas to all. : )

 

[Rob80b]

It seems we may not be getting back on topic just yet then.
Have you looked at the THD measurements I posted on the previous page? (LINK) Off the top of my head I can’t think of too many electrodynamic open-back headphones (not made by Focal) that have the combination of low bass extension and low bass THD that these Sennheisers have. ................

Again, I'm not sure how this theory started in the first place, let alone how it has gotten repeat play enough to be accepted as fact.

Not to point fingers....but the song goes like this....
"There's a little trick you can do to increase perceived bass response in low frequency limited devices: Add second harmonic distortion to the low notes to "bloom" them up a bit. This is often done in the Bluetooth portable speakers, which, due to their small drivers and overall small size, have problems reaching way down into the bass. By selectively adding 2nd harmonic overtones to the low notes, overall bass energy is increased—albeit at a higher frequency than the original tone—and your perception will be a euphonic warming of the bass. It's euphonic because the second harmonic is exactly an octave above the primary tone, so it remains in harmony with the original music. On the other hand, it is a distortion, and those with well trained ears will hear the bass as slightly less precise and authoritative."

 

[greggf]

Yes, jude and Rob, that's how the rumor got started.

 

[jude]

...But the THD of the HD 800 S was intentional as Sennheiser is not capable offering a linear bass extension on their open back dynamics, so they tried to artificially boost the bass region by adding harmonic distortion to the headphone. It is not the ideal solution but it works as I did notice some added thickness in the lower bass regions before measurements were available...

I've seen this suggested before, but I'm not sure what the origins of this explanation are.

Look at the measurements I posted. Any increase in harmonic distortion is minor (HD800S versus HD800), and I haven't seen anything in our distortion product ratio plots that support this theory. Further, when I brought up this topic with Axel Grell in London (at CanJam) after having measured both headphones on the GRAS 45BB-12 (with similar results), he was not surprised. There was no deliberate distortion added. When I asked him how they achieved the difference in sound signatures, he smiled (and that's as far as I'll comment on that).

Again, I'm not sure how this theory started in the first place, let alone how it has gotten repeat play enough to be accepted as fact.

Not to point fingers....but the song goes like this....
"There's a little trick you can do to increase perceived bass response in low frequency limited devices: Add second harmonic distortion to the low notes to "bloom" them up a bit. This is often done in the Bluetooth portable speakers, which, due to their small drivers and overall small size, have problems reaching way down into the bass. By selectively adding 2nd harmonic overtones to the low notes, overall bass energy is increased—albeit at a higher frequency than the original tone—and your perception will be a euphonic warming of the bass. It's euphonic because the second harmonic is exactly an octave above the primary tone, so it remains in harmony with the original music. On the other hand, it is a distortion, and those with well trained ears will hear the bass as slightly less precise and authoritative."

Yes, jude and Rob, that's how the rumor got started.

I decided to examine this further here, with the one HD800 and the one HD800S we have. Here's what I did:

---

• First I did a quick FFT plot of the HD800 (16,000 points, no averages), playing a 40 Hz sine wave. I ended up with a plot that looked somewhat like this:
  
  CORRECTION 2017-12-28 03:16 EST: In the first graph (below), where it reads "Averages (Power): 0" it should instead read "Averages (Power): 1". Similarly, in the third graph, where it reads "Averages (Power) = 0" it should instead read "Averages (Power) = 1".
  
  
  
  
  
  As you can see, that's not particularly detailed, so I took advantage of our audio analyzer's ability to do extremely detailed FFT's, opting for 1.2 million points, and doing three averages. Setting it to 1.2 million points provides a much more detailed plot, and the averages help remove random noise (better revealing the actual noise floor, too). Without having moved the HD800 from the above plot, here's the FFT re-run with 1.2 million points with three averages:
  
  
  
  
  
  And here are the two overlaid:
  
  
  
  
  
  NOTE: The examples above are actual measures of the Sennheiser HD800, but these were just quick preliminary measurements done without turning off the building's heating / ventilation systems. Even though we do employ a lab-grade acoustic and vibration isolation enclosure, the measurement gear is obviously very sensitive, so we still turn off the HVAC systems when we're doing audio measurements to lower the noise floor. As a result, the example measurements above may have a higher noise floor than the measurements that follow (which were done with the building's HVAC systems turned off).

• Again, the above measurements were just done as examples of two different FFT resolutions. Now let's get to the actual comparisons. Following are FFT spectrum measurements from the first seatings of the Sennheiser HD800 and Sennheiser HD800S, set to 1.2 million points and three averages, and playing a 40 Hz sine wave. I made the plot lines a bit thicker (and different colors) to try to make the two plots easier to distinguish from one another:
  
  
  
  
  
  Here (below) is the same plot with cursor lines showing the difference at 80 Hz (80 Hz being the second harmonic of the 40 Hz sine wave fundamental tone, since we're examining the theory that the Sennheiser HD800S's richer sound is due to (as quoted above) deliberately added 2nd harmonic overtones/distortion):
  
  
  
  
  
  The difference between the Sennheiser HD800 and Sennheiser HD800S at 80 Hz (H2) is only 2.783 dBSPL. Keep in mind that the center of this 2.783 dBSPL difference is occurring around 45 dBSPL lower than the fundamental tone. While the Sennheiser HD800S unit we have here does (to my ears) sound like other HD800S's I've heard (richer than the Sennheiser HD800), I do not believe this measured difference at 80 Hz suggests deliberately added 2nd harmonic overtones/distortion (to the HD800S versus the HD800).
  
  
• I decided to do a second seating of both headphones, also increasing the size of the headband for both headphones by one click on each side. Here (below) are the FFT spectrum plots from the second seating:
  
  
  
  
  
  Again, this time (below) with cursor lines showing the difference between the two in this seating at 80 Hz (the second harmonic of the 40 Hz fundamental test tone):
  
  
  
  
  
  The difference in this plot at 80 Hz is lower than the previous one, measuring only 1.673 dBSPL. As above, the center of this difference is about 45 dBSPL below the 40 Hz fundamental tone.

---

Again, keep in mind we only have one Sennheiser HD800 and one Sennheiser HD800S here at this time. I may measure more.

Based on discussions with Sennheiser and the above measurements of the Sennheiser HD800 and HD800S we have on hand, it does not appear there was any deliberate addition of 2nd order harmonic overtones/distortion to the HD800S as has been the common theory for the past couple of years.

If you have any other suggested tests you'd like to see performed on these two units here that you think might generate different results, let me know. That said, based on the THD measurements I posted in this thread earlier, and other measurements we've performed on these two headphones (also on the GRAS 45BB-12), I'm not surprised by the above results.

The measurements in this post were made using:

• GRAS 45CA Headphone Test Fixture with:
  • GRAS RA0401 High Resolution Ear Simulators
  • GRAS KB5010/KB5011 Anthropometric Pinnae for 45CA
• Audio Precision APx555 Audio Analyzer
• Audio Precision APx1701 Transducer Test Interface
• Herzan custom acoustic enclosure

 

[pietcux]

Wow, your test equipment is very good and you know how to use it properly, thanks Jude.

 

[greggf]

Good equipment, good ears, & good explanations. It separates facts from conjecture.

 

[amartignano]

Thanks Jude for the measurements and clear explanation!

I think this: if an increase of 2nd harmonic distortion exists, it was not deliberately added, but it probably was a side effect of the presence of the resonator used to tame the mid-highs.

 

[Rob80b]

I decided to examine this further here, with the one HD800 and the one HD800S we have. Here's what I did:

Thanks Jude for taking the time to do this.... clears up a few things...guess this should be moved over to the 800S thread and/or to show a similar reading of the 660s vs 650/600s. : )

 

[daltonlanny]

Not trying to disagree with, or question Jude or anything, and definitely not trying to defend Tyll Hertsens, or anyone else, but several other people, including several publications, besides Tyll at Innerfidelity, have measured significantly higher bass harmonic distortion in the Sennheiser HD800S compared to the regular HD800 below 80 hz.
This was with both headphones available to measure at the same time too, just like with Jude.
Can this be explained?
I love both the HD800 and the HD800S, but, the 800S to my ears, does sound very slightly muddier in the bass, and isn't quite as distinct or clear in the bass, compared to my regular HD800, and the 800S definitely does not take to boosting the low bass with an equalizer as well as the regular HD800.

 

[pietcux]

Not trying to disagree with, or question Jude or anything, and definitely not trying to defend Tyll Hertsens, or anyone else, but several other people, including several publications, besides Tyll at Innerfidelity, have measured significantly higher bass harmonic distortion in the Sennheiser HD800S compared to the regular HD800 below 80 hz.
This was with both headphones available to measure at the same time too, just like with Jude.
Can this be explained?
I love both the HD800 and the HD800S, but, the 800S to my ears, does sound very slightly muddier in the bass, and isn't quite as distinct or clear in the bass, compared to my regular HD800, and the 800S definitely does not take to boosting the low bass with an equalizer as well as the regular HD800.

I sometimes get so much lost in the music, that I am in the end surprised which headphone I have on. I mean all cans that I own right now are inside a certain range and the music completely takes over. Does this happen to you too at times or are you always listening to find the specific flaws that each headphone has to you?

 

[L8MDL]

I thought this was a HD660 thread

 

[amartignano]

I thought this was a HD660 thread

It became a sort of analysis of last important Sennheiser headphones different evaluations.
A bit OT, but quite interesting.