I was hoping the 400S would be the "400i-with-the-bass-i-want", but it doesn't seem to be the case. 
 
Thanks for the honest review!

One thing I have noticed is these headphones are very source focused. I used a LG G4, and got good bass, I tried an iPhone Mid bass was push forward, I tried a couple of portable amps and the sound changed again. Good write up as well, I like the table for the ranking of frequencies.

@bjamn  I feel that if you put the Focus Pads or Focus Pad As on the 400S, they definitely get closer to what you're looking for.  They still are smoother than the 400i, but does get the better bass extension and quantity.  

Hey Grizzly, how do you feel these compared to something like the closed ZMF x Vibros? I was wondering. Because I currently sold a good portion of my gear, had too due to health issues that were everlasting. So I was eventually hoping to grab a mid level phone that Could be driven from my DX90 paired with my iBasso PB2/Meier 2Move. I am between this and phillips x2, which from what i have read is a fantastic headphone with many of the nitpicks of the original x1 corrected. Would you say that this is close to the sound quality of the Vibros? I know it would sound difference due to the difference of housing, and open versus closed.

Vibro has my vote for sure. It has bass extension slam and good mids, better all arounder. But it may be harder to drive. I would prob pick the x1 even over this because I like bass but this has a better midrange and a less grainy sound. I think the x2 is my next hp though and I haven't heard it yet but it is most def credible.

Bass speed? Bass texture? overly wolly? That's some good audiophile jargon nonsense. I'm wearing the HE400S and listening to hip-hop, and the bass is fine. You can EQ it up a few dB at 40 Hz if you want, but there is nothing below that in hip-hop music anyway, only pipe organs go down to 20 Hz (load Notorious BIG in Audacity if you don't believe me). The majority of people are accustomed to listening to bass boosted systems and don't recognize proper frequency response when they hear it.

@rubley Instead of calling (parts) of a person's review "audiophile jargon nonsense, why don't you ask him what he meant by those statements.  Audio is entirely personified when we try to describe it with our own words.  It's highly subjective in nature, and definitions may vary slightly from person to person.  
 
Texture tends to deal with the fluidity of the bass, it tends to be a very subtle area.  The easiest place to hear it would in light vibrations (best words I have to describe areas where bass texture tends to really be strong) due to something like a bass guitar, cello, or even a double bass.  (distant) Explosions also contain texturing if they are done in that fashion.  It may also not be entirely a function of frequency, it may have to deal with how the bass frequencies play with each other.  As stated, a few dB around 40 Hz may help this area (actually, it does, quite a bit!).  
 
Bass speed is a perceived speed and has much to do with decay.  A quicker decay can create a feeling of faster bass.  It generally tends to go together with a tighter mid bass, though doesn't always.  
 
Just FYI, the HE-400S does have a bit of a bass boost on it, especially when you swap to the Focus Pads that come with the HE-400i and HE-560 as they seal better due to the pleather outer walls (there may be more to it).  

"fluidity of the bass" is also meaningless jargon. Decay is a word that is appropriate for discussing the characteristics of a driver (provided there are measurements to back it up), "bass speed" is not. There are appropriate technical terms to describe the behavior of a driver, there is no need for vague terms with no technical meaning. A person's opinion is ENTIRELY subjective, making it all but worthless. If definitions vary from person to person how can two people communicate?? That's not how language works, without common definitions, information cannot be conveyed. Which is way many of the descriptions in this review are nonsense.

@rubley , I present to you the "Describing sound - a glossary of terms": http://www.head-fi.org/a/describing-sound-a-glossary
 
Varying from person to person is a perturbation from the original meaning (whatever the original is), the idea still stems from the same idea/description.  People may have differences in terms of what actually is bright, what actually is dark, etc.  Actually, this happens quite a bit with just about every literary work, people debate about what an author meant when they said X.  

Great, so let look for the terms in the original review:
 
Bass speed: Not found
Bass texture: Not found
Bass extension: Not found
Bass control: Not found
Bass impact: Not found
Overly wolly: Not found
Sound separation: Not found
....
 
I'm not going to bother going any farther. Get my point about meaningless jargon now?

These words are actually in the dictionary.
Texture - A perceptible pattern or structure in reproduced sound.
Speed - A fast system with good pace gives the impression of being right on the money in its timing.

These words aren't defined in the dictionary since they either have obtained their meaning through other words in the dictionary or are being used in the literal sense.
Extension physically means extending into either the lower lows or higher highs. It's a literally definition. Since the word is describing bass, it's extension into the lower bass.
Control is actually synonymous with "grip" and is used in the definition for "weighty".
Impact is used in the definition for "fun" and "punchy". On Head-Fi, it's gained its meaning being synonymous to a stronger punch. Typically a punch that is felt a little more. Would be synonymous to a fuller punch.
Separation is synonymous to saying it has good imaging. More specifically, instrumentals are clear from one another. A sense of depth (once again, in terms of imaging) is typically associated with it.

These words aren't in the dictionary, and I'm actually not sure what they mean.
Wolly, I personally never understood the term wolly, nor have I used it. You'll have to ask the writer for this one.