Sennheiser HD800 Certificate for Frequency Response Arrived - Page 3

I envy you! First in Europe*, smoothest frequency response so far!

It won't be too long till I get my pair, though!


I've heard that Switzerland will receive a select few dozens with particularly perfect frequency response. No definitive confirmation, though.


* Actually I know of a few German guys who received theirs three days ago, but who cares!
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I'm taking Sennheiser's measurements with a grain of salt. I remember their HD280 graph:

http://www.sennheiser.com/sennheiser/products.nsf/resources/8F67C484DF2CD44AC1257482003BEB49/$File/HD_280_Pro_GB.pdf

Yeah I just don't believe that curve in the least. At least that one extends farther than the HD800's...

One has to be aware that the «curve» has very low detail resolution: apparently it's made of ⅓-octave band-limited noise. But I think it's a valid measuring method. With headphone measurements higher resolution means more misleading detail which in the end doesn't necessarily correspond to the individual listening impression.

As to HRTF equalization, I think there's no universally valid method. Each is as good as the others. After all the diffuse-field equalization at hand is one of the most respected equalization methods and likely does the angled-driver design justice.
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Mine.

Just out of curiosity, is there a reason some of you have hidden your serial numbers? It actually would provide useful information to the community to know them.

Mine:



Hope you guys can read this....I'll try to get a better shot tomorrow...no scanner on hand and I didn't have the correct
lens on the SLR. I'll be following this thread closely. I feel like I have a custom hand built and tested headphone that
I truly love here. It's going to be interesting to see the differences in sets.

Personally, I think Sennheiser is out of their minds for giving out these graphs, but they did...

Fortunately for Sennheiser, as transducers go, the curves look fairly consistant. And it appears the DF-interpreted curves fall within pretty tight plus/minus 2db or better tolerance, quite good for a transducer.

Interpreting FR curves (especially for headphones) is fraught with difficulties. But it looks like the dominant feature in these plots is a 3Khz dip and a small peak at 6Khz.

I think that a reasonable way to assess the 6khz peak is to reference it to the dip nextdoor at 3khz. So far, the 6khz peak rises above the 3Khz dip (as near as I could read them) by:

SN#459 2.5 db
SN#349 2.5 db
SN#1230 2.5 db
SN#685 3.2 db
SN#517 3.5 db
vai 2.5 db

So the range is 1 db with SN 517 (kelvinz) being the "hottest". I kind of doubt that this would, by itself, account for the various listeners reported differences. But this is just 6 samples, so we shall see.

I suspect the reported differences are more due to honest differences in expectations and preferences. And remember, these curves look nice and flat, but if you believe that some other curve than the diffuse field correlates better to natural reproduction, all bets are off!

But it is impressive that, given the target response that Sennheiser decided upon, they have been able to achieve it pretty consistantly.

I got my FR "curve" today. My SN is 276. I don't have a scanner at my house (I do at work so I will scan it tomorrow) but my 6k peak seems to be at about 4 db.

These look like 1/3 octave curves which, while they can be informative, do tend to smooth out the worst appearing peaks and valleys.

You may be right that the differences are due to preference/expectation, since the treble "anomaly" is fairly consistent. However, I do believe that a rise from 3 to 6 kHz, which seems to be indicated in all these Senn measurements AND the very different Headroom measurements is likely real, and again correlates well with what I hear in the treble, which is a slight emphasis in that region. Some people may hear that and "prefer" it; however, it exists, and even a 2-4db rise in that area, where the human ear is VERY sensitive, is very likely to be audible.

In that case, the treble rise could be even more pronounced.

First, I recommed reading this for anyone who hasn't;

Stereophile: Between the Ears: the art and science of measuring headphones

The very different Headroom measurements are not so different as it may appear. If you apply the Diffuse Field EQ curve to the Headroom curves, one ends up with something like Sennheiser's curve. I do not know for sure exactly what curve Sennheiser applied to the "raw" measurements to derive their plots, I know there is an IEC standard but whether that's what Sennheiser used or some other "hybrid" curve, who knows. But there is disagreement as to what the optimal curve is (part of the referenced article above).

So the point is, there is no what to say for sure whether features of measured FR are right or wrong, without consensus it's just unknown. The treble "anomaly" you refer to may actually be optimal...

So we are forced to just listen.

I am a 15+ year Stereophile subscriber and am a BIG fan of Keith Howard's articles. I read that article the day I got that issue. I thoroughly understand the difficulties in measuring headphones. I worked for a major microphone manufacturer for 8 years, and I have taught a college class on audiology. I GET IT

I understand that one cannot rely on one set of measurements, especially without knowing all the details about how they were taken. But when multiple different sets of measurements seem to show some similar trends, AND the listening you recommended (which I obviously did as well) seem to also correlate, well...I have no issue calling that "evidence"

Your point about whether the peak is an "anomaly", or "optimal" is an interesting one, and of course, as you have also wisely pointed out before, that will only be in the ear of the listener, at the end of the day.