kimdeug@kimdeug, you say this...
"I can see where these debates about graphs will go soon. And for majority of the people it is not important all this numbers and curves, because this hobby is for fun and pleasure. Only the personal ears will do the final judgment for each person individually."
...but I actually disagree. I'm actually giving a video seminar presentation at the upcoming HBK (Hottinger Brüel & Kjær) Electroacoustic Conference titled "Audio Measurements As Consumer Content" and will discuss this very topic.
Today, measurements have a huge effect on the reviews and impressions of audio gear. Huge. When a new thread is posted about a headphone, how many posts does it take before someone is requesting measurements? After measurements are posted, how impactful are those measurements on the perception of the products? I think it's quite clear in this discussion the measurements have had a very big effect.
Looking at crinacle's review, he recommends EQ settings derived from his comparison graphs, saying:
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It’s fairly easy to visualise the differences between the two on FR, considering that both headphones have the same housing and drivers just with tweaked tuning.And for those who already own a HD800S, here’s an EQ profile for you to “taste test” the HD8XX:Low shelf: 40Hz +5.0dB
Peak: 350Hz +3.0dB, 0.2Q
Peak: 700Hz +2.0dB, 1.0Q
Peak: 1,550Hz -7.3dB, 0.8Q
Peak: 5,800Hz -3.5dB, 10.0Q
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That more than suggests that if you EQ the HD800S using those settings, you'll hear a close approximation of the HD8XX. That's one of the reasons I'm asking if anyone knows how crinacle decides where to normalize the two, especially if EQ settings are going to be derived from them. Did he use the same voltage used to drive one to drive the other? Did he arbitrarily pick what looks like ≈900 Hz?
For the most recent measurement I made for the 8XX that Drop posted, we chose from several different normalization options I provided them with (which I'll get back to shortly). Also, they wanted the unit with final voicing to be measured on the 45CA (60318-4) so that it could be compared to the Harman Target, if they so chose -- but also to have measurements that were perhaps more comparable to the other measurements likely to come out, since maybe only a couple of reviewers out there have the Brüel & Kjær 5128 that has become our primary measurement fixture. That's why we went with the 45CA.
Getting back to normalizing the measurements (HD8XX and HD800S): Again, I gave Drop several different comparisons normalized at different frequencies, the idea being to choose something that sounded most like what we were hearing. We ended up mutually choosing the comparison normalized at 1.5 kHz -- that comparison also happened to compare somewhat closely with the internal development measurements from Sennheiser. But even I have some misgivings doing this (choosing which frequency to normalize at), as it's still a choice based on what we felt was the closest (of the options I provided) to what we were hearing.
Something we've been testing for a while is setting our voltage levels (into the headphone) using white noise, rather than just choosing a single frequency to do that with (as is customary). I've presented this to one of my friends at Audio Precision, as well as to Head Acoustics when they recently visited, to see what they thought of the idea. Head Acoustics even compared white-noise-set comparisons (the way we're now doing them) to music-material-set levels, and found they were comparable, which was nice to see. For more on normalizing, and what we're doing, please read this post I made on Head-Fi:
https://www.head-fi.org/threads/meze-audio-elite-the-new-isodynamic-hybrid-array-headphone-official-thread.959445/post-16548509
So, in the interest of this discussion, since I didn't have any noise-level-set measurements with the HD8XX, I did a comparison between the headphones that way, and here's what I got (keeping in mind this is just one seating, but it's close enough to our averaged non-noise seating that I'm comfortable with it):
Again, while this is just one seating, I'm comfortable with it as a representative seating (one I'd include in the eventual noise-set average for the HD8XX). When we post frequency response measurements (unless otherwise noted as above), we always use multi-seat averages.
How did our previous 1.5 kHz normalizing do compared to this? Well, as you can see, we were a bit off, but closer than any of the other measurement comparisons I've seen so far. As it turns out, the point at which they cross here is around 1.272 kHz -- so, again we were off a bit, but our 1.5 kHz comparison was still the closest of the normalized options I gave Drop, and, again, the closest of any of the measurement comparisons I've seen so far.
Now, if you take that noise-set measurement above -- which, to be clear, is completely unnormalized -- imagine dropping 7.3 dB at 1.555 kHz (where they're perhaps less than one decibel apart in the measurement above), or dropping 3.5 dB at 5.8 kHz (where they're essentially equal).
Again, @kimdeug, I respectfully (but vehemently) disagree with you. Measurements shape perception in the audio hobby perhaps more than ever before.