WTF Revisited: Sennheiser HD700 Stories, Review, and Measurements

I don't think with either the HD800 / HD700 comfort was the only goal, and I think the 6khz "spike" is deliberate and not just a product of the comfort. It seems this 6khz region is what helps in perceiving the huge soundstage. When I EQ it out, the soundstage sounds more ordinary, and the headphone starts to sound more mundane and I am no longer interested. I experienced the same thing between the HD800 and HD800S, the HD800 I seemed to perceive a bigger soundstage. Perhaps they went a bit too far with the spike in the HD800/HD700 and hence many people's preference for the HD800S, but I still like the HD700 better than the typical "neutral headphone"

Pre HD-7xx/HD-8xx I honestly never liked headphones in general that much because they sounded too closed in to me. Sure, I'd have a pair of 5xx or 6xx series around when I couldn't listen to speakers, but they weren't my primary mode of listening. The big soundstage of the HD700 and even moreso the HD800 converted me from listening to speakers to listening to headphones as preferred choice. I think they just sound very different than the typical headphone and their unique sound just appeals to me - they sound more like speakers than typical headphones.

I think the HD700 could be improved upon like the HD800 was , but I don't think that would involve drastic changes to its FR - just some tweaking like the HD800S had. For speakers fans like me, the acoustic nightmare seems to better emulate the room response, reflections, and soundstage of a speaker much moreso than the typical headphone.

 

Show me a set of speakers with a treble spike like that. I’m sure you dorks could, but its going to be a rare find.

 

You don't strap speakers to your ears. They reproduce sound at a point some distance away from you, which then reflects and diffuses off multiple surfaces while simultaneously reaching your ears which hear a combination of direct and reflected/diffused sound. In addition to hearing the drivers in the speakers themselves, you also essentially hear the room; so a simple speaker frequency response curve cannot capture all of these elements. From my listening though, that experience is best represented by the sound of the HD7xx-HD8xx series; the perception seems to be diminished if you EQ the 6khz bump to flat. The HD700 sounds worse/weird vs HD8xx because it also has the big 3khz dip that the HD8xx doesn't have, a likely limitation of the smaller driver and enclosure.

If you think about it, headphones are an extraordinarily unnatural way of listening to sound. There is no natural listening situation in normal life where you have sound beamed into your ear canals from 1" away with no opportunity to reflect or diffuse in the environment - whether its listening to speakers or simply someone talking to you. This is why I feel the science of audio in headphones is in its extreme infancy, I believe there is still a long ways to go to reproduce that natural sound experience. One field that is working on it a lot is virtual reality; immersive audio engineers found the typical headphone design was not adequate in providing natural, lifelike sound; they found the typical design seems too much "in your head," instead of "in the world". So in addition to developing sound processing systems VR sound engineers are also experimenting with new headphone designs, such as ones that rest off the ears [valve index] or above the ears [oculus quest] in order to attempt to capture that "real life" sound. Sennheiser HD7xx-HD8xx is the first "hifi" headphone I've heard that takes a step in this direction (there may be others, they are just the first I've heard), and I think there are a lot of factors that one can attribute to it - with the 6khz bump in the "presence/brilliance" range likely being one of them. Since there is no opportunity to place the headphone drivers 8ft away from your ears like speakers, the sound engineers need to play psychoacoustical tricks, essentially, to emulate that 8ft away experience from 1" away...

 

Complete nonsense. Measuring speakers measures the effect of the room as well. The microphone is literally in the f'ing room. The hd700/800 are just treble monsters. If you like that it’s fine you don’t need to make up BS excuses for it.

I heard a modded hd800 and thought it was still not my cup of tea but the change was miraculous. Soooo much better.

listen to what you like.

 

A simple microphone measuring frequency response does not capture the experience of direct+reflected+diffuse sound being heard by a human with stereo ear canals and a brain interpreting the incoming sound. It captures frequency response at a single point in space.

Since headphones cannot produce direct+reflected+diffuse sound as they are sitting 1" away from your ears, comparing them to the sound profile of something 8ft away which can produce that type of sound is not a valid comparison IMO. Again, this is why VR devs are changing the designs of headphones, because the standard good ol' headphone design is inadequate for producing natural, lifelike sound that might appear it is coming from the environment instead of within one's own head.

Regarding the HD700 and HD800 specifically, I do not think they are the "endgame" of this type of more expansive sounding "hifi" headphone but rather the starting point. The HD800 I also found too offensive in stock form, I think they went a bit overboard with the FR curve in trying to reproduce that sound. The HD700 I didn't find that offensive unless paired with harsh amps, in which case it could also be offensive like the HD800; but the HD700 tends to sound "weird" compared to HD8xx, likely because of the big 3khz dip - so it is not ideal either. However, I do think the HD800S & HD820 are both excellent in stock form - again, as long as you don't pair it with an amp that has very harsh high end as the boosted treble will exacerbate the harshness. As mentioned above, I think the elevated treble in 6khz region is just one of the psychoacoustical tricks that was employed in HD7xx/HD8xx to attempt to deliver a more expansive, "out of your head," more natural sounding soundstage.

It's worth keeping in mind my perspective as well. I am someone who traditionally does not like headphones because I feel they sound too "closed in" / "in your head" etc. Not lifelike sounding. I always owned headphones for when I couldn't use speakers, but considered them an inferior necessity rather than something I would prefer to listen to over speakers. There are only a select few headphones I actually listen to and think "this sounds as good as / better than speakers" - and those are primarily ones in the HD7xx-HD8xx series. So, someone else who does like the general headphone experience will likely have a much different perspective than me on HD7xx/HD8xx as they are very different than the typical headphone design.

 

Ahhh fooey. More nonsense. CSD measurements of speakers do capture reflections. My speakers are dead flat and super clean. To best reproduce that sound, I need a headphone that is also dead flat and super clean. Which doesn’t really exist because Sennheiser can get away with selling crap like the hd700 to you.

you’re just liking the boated treble and some sort of perceived soundstage increase. That’s all. No need to make excuses for preferences. Better to understand them and bow down to them.

 

I don't think we are necessarily disagreeing on all points, perhaps I am just saying it a bit differently.

The primary speakers I have listened to and enjoyed audio on for 20 years or so are the PSB Stratus Goldi - which are fairly neutral - and I amplified them with solid state (Rotel RB-1090 primarily) amplification which some may say in general tends to lean towards the bright side; so perhaps a neutral-bright signature. When not listening on those I am using solid-state amplified studio monitors, which again tend to be neutral-bright.

I have tried headphones that many have said were "neutral" such as the HD600 on various amps and found the sound to be unremarkable and typical headphone-like in-your-head soundstage. Also had plenty of headphones before that, from hd2xx-hd5xx and found all of them serviceable but unremarkable. It was not until the HD7xx/HD8xx that I found a headphone to have a soundstage that sounded more similar to the speaker sound I like. I did not engineer the HD7xx/HD8xx so I cannot claim to know exactly the full repertoire of psychoacoustical methods that create said larger perceived soundstage effect in designing the headphone, but I do know when I EQ out the 6khz bump with software like Sonarworks I no longer like the sound of the headphone - with the soundstage again starting to sound small. So I do attribute that 6khz bump to be at least part of the perceived soundstage increase.

I will say my own preference, if the headphone does not have large soundstage I generally do not care to listen to it no matter how good it otherwise sounds - lifelike soundstage is the most important quality to me as otherwise I perceive the audio as sounding artificial.

 

So there you said it. Perceived soundstage is the most important thing to you, above FR. And for you, the treble peak enhances perceived soundstage.

for me, soundstage is very low on my priority list because well, beggars can’t be choosers and in this market I’m definitely a beggar.

I think that sums it up. Cheers buddy.

 

@purr1n , how would you describe the Sony MA 900 headstage (and I guess overall sound) to the HD700/800.

 

I don't think the 6klhz boost is the only thing that increases perception, but I do think it is part of the equation. You mention point source drivers placed away and in front of ears help perceive expansive headstage. But why is that? Where does this show up in the measurements? That's the thing, the brain/ear perception phenomenon can't be measured by electronic tools.

When one is listening to speakers and perceiving direct+reflected+diffuse sound, the ear+brain combo doesn't perceive the location of frequency range in a consistent way.

For instance, if one were to play an 80hz tone away and in front of the ears, the brain perceives this frequency as largely omnidirectional and theoretically it wouldn't be perceived much differently than if it was directly in front of the ears. However, if one were to play a 6khz tone away and in front of the ears (which is in the "presence/brilliance" range), one would be able to better pinpoint that the sound is not coming directly from the sides. In fact, it might draw one's brain's attention to the fact that the sound is not coming from the side of the ears given that specific frequency's characteristics.

The same applies to loudspeakers. When playing sound, even if the sound is reflected off another surface the brain always can locate the original point source of high frequency sound as the original sound source. The reflected sound is heard and located also, but the original firing source of the tweeter is near always located first. This is one of the reasons upward firing Atmos speakers that bounce sound off the ceiling, for instance, aren't as convincing as speakers actually placed on/in the ceiling. So in truthfulness, you really can't compare something 8ft away to something 1in away, as the brain will always be able to locate the source 8ft away as being 8ft away if the frequency is high enough and vice versa.

So this being the case, it would be very difficult to position a driver in the traditional headphone driver position and use a traditional frequency response curve and having anything remotely approaching a speaker sound. The listener would always perceive the sound as coming from the sides/inside the head, and this is not how one positions loudspeakers in a room (or how one sees a live concert, etc).

As I did not design the headphone, I do not know all the psychoacoustical tricks they used, whether driver positioning, angling, cup resonance, FR tweaks, etc, but I do know the soundstage is very different than a traditional headphone due to its design. I don't think its only one single element, but the culmination of several.

It sounds like you are talking about the original Rift. That used a standard Koss Portapro driver in a custom enclosure and was bassy. It was the first VR device and most of the development was done on the software side, wasn't that much development put into the headphone hardware likely because they wanted to be first to market. (the Vive that came out at similar time had no headphones at all).

But 2nd gen VR devices they have put a lot of development into the actual headphone hardware design to rectify the deficiencies of standard headphone design for lifelike audio perception. The Oculus Quest has a driver built into the front side of the headset strap that sits away from the ear and fires sound in front of the ear (sounds a little like your description of the HD700/HD800 driver ) It actually is very bass-deficient [common criticism] with mostly mids and high frequencies but is extremely effective in presenting a lifelike sound environment. The Valve Index has a headphone but it floats in space off the ear - basically a close-range speaker floating out in space. There are different ways of tackling the same problem that is traditional headphone design (headphone sitting on axis, on ear) not working for making a convincing spatial audio experience, and thus different approaches will vary in their overall design and FR response.

 

Huh? What? That's what HRTF/PRTF are intended to describe. The only insurmountable problem for headphones alone is crossfeed.

I suggest writing less and lurking more.

 

You get a deeper headstage by reducing the area between 1kHz and 5kHz. HD800 is exemplary at this. Pretty flat between 100 and 1000hz, than a deep dip, than a raise.
Sennheiser has done this with HD660s to push the stage slightly out of the head and create some depth, too.