[avitron142]

 
Power drawn from iPhone 6 for everything except the HE-560 comparison which was done using an iPhone 6 > HiFiMan EF-100.  I do feel that the 6 is enough to power both the 400S and 400i, I hit about 7-8/16 volume on the 6 with the S and 8-9/16 with the i.  I didn't have much time to do any other hardware comparisons unfortunately.  

Volume != driven properly. I don't doubt the iPhone 6's capabilities, but I do think it may not be enough for any definitive listening tests. just my 2 cents...

 

[tinyman392]

  Volume != driven properly. I don't doubt the iPhone 6's capabilities, but I do think it may not be enough for any definitive listening tests. just my 2 cents...

Either way, the roll-off was there, regardless of whether or not it was driven properly...  Even when powering through the EF-100.  I stand by my statement...  

 

[avitron142]

 
Either way, the roll-off was there, regardless of whether or not it was driven properly...  Even when powering through the EF-100.  I stand by my statement...  

Go for it. And perhaps I'm wrong too... but where was the rolloff point? I'm just curious about that; I've heard ~35 hz very well on normal listening volumes , so I'm a bit confused.
 
Also, in the beginning of this thread, we talked about the amplifier bringing out the planar quality of these; specifically the deep end of the bass. So my guess is driving it properly is quite important for sub-bass tests. However, since you did use it with your EF-100... 

 

[Gino]

Same here. I hear as low as 27hz through my Asgard. I suspect the difference lies with the gears people use. But the reality is people will have different
gears and perhaps expectations. I will not insist on how good these are. For everyone else, it either is or is not. 

 

[tinyman392]

  Go for it. And perhaps I'm wrong too... but where was the rolloff point? I'm just curious about that; I've heard ~35 hz very well on normal listening volumes , so I'm a bit confused.
 
Also, in the beginning of this thread, we talked about the amplifier bringing out the planar quality of these; specifically the deep end of the bass. So my guess is driving it properly is quite important for sub-bass tests. However, since you did use it with your EF-100... 

EF-100 wasn't enough to pull it out unfortunately (it's not the warmest amp IMO though).  Under powering was a thought as well at first.  With that said, the last portion of this post does go into detail about how I feel about amplifiers and the sound impact they make and how they make it from a personal level.  Maybe I'm biased?  
 
Now, I'm not saying that it doesn't get that low, it can, heck, I didn't notice the rolloff until I compared with every headphone I have above the 250 dollar price point.  That said, giving you a number, I can't do subjectively.  By ear, I feel that it was around the same area, maybe slightly above (can't say for sure if it's actually above or the higher quantity of the P7 that is tricking my brain), where the P7 rolls off.  Remember, roll off doesn't depend on how far down you can hear, it is a representation of loudness in contrast to the rest of the bass spectrum.  These can get low, I'm not questioning that.  
 
Objectively...  You've seen the graph, and disagree with it.  I disagree with it to a point (I hear a roll off, but nothing that drastic), though time domain also plays a huge role here as well. I'm not the best at reading square sine waves, I prefer a waterfall personally.  Slower decay, which I feel the 400S does have (subjectively), can make the quantity feel larger at times (this goes for the bass as a whole, from sub to mid, for the 400S).  Though the 400S does have a measured roll-off, I feel that it was amply adjusted for (smart tuning choice here) with the thicker sound that the 400S employs.  
 
From the amps I've had been able to play with (Not a huge repository, but a good number: Vamp Versa, Silverstone EB03+EB01, Aune T1, EF-100), the amp itself will flavor the sound more than the power it gives (which is why some combinations will work a lot better than others).  The EF-100 is a cold (even colder than my iPhone) source that is unforgiving in many aspects (it's a love hate thing I have with it).  It helps out the 400S by pulling out some more details out of it, but not as much in the bass.  If you find an amp that can help the sub-bass (many do), I'm sure you can get a really nice euphoric sound out of the 400S.  
 
One final note though about normal listening volumes...  That varies from person to person.  I've a soft listener, some might say excessively so.  My volume rarely will hit 80 dB (this is done by ear of course).  
 
____
 
A few notes, I'm not saying that the 400S can't get low, it can, it most certainly can.  I do feel it can be overshadowed by the upper bass at times.  The 400S is a headphone I respect and enjoy listening at times; though it isn't my preferred signature, my preference does hang towards a dead neutral, almost analytical sound.  It's a great headphone, do not let anything I say stop you from enjoying it.  
 
EDIT 1: edited some statements above.
EDIT2: this really reminds me of the binary opinions about the P7 either having too much bass or being just a little bassy.  Though the mystery of that was found to be seal issues (Tyll showed this objectively as well).  There is a lot that goes into bass response.  Maybe we're both right?  

 

[gotak]

  Volume != driven properly. I don't doubt the iPhone 6's capabilities, but I do think it may not be enough for any definitive listening tests. just my 2 cents...

 
Some folks are too enamoured of amps and the "magic" it can do.
 
I tried a test and LG G3 direct to HE-400S sound exactly the same as LG G3 to amp then HE-400S. So what does that tell us? Maybe it isn't the ability to drive that's the limiting factor.
 
As for roll off of this or that, well the measurement is what it is. Different folks will say different things no matter the measurement or alignment of the planets. You can find people who think the old school Beats are great if you look hard enough...
 
What I am saying is I don't think anyone can for 100% sure decide if they'd like this set without listening to it themselves. Personally, I trusted Tyll's hints about it from the trade show since everything he recommended has worked well for me. And this time is no exception. My initial objection to the treble has now dissipated after breaking in my ears a bit.

 

[Cotnijoe]

Hey yalls. Ill be getting a review unit of the 400S from HIFIMAN in a few days. Ill prolly chime in on this discussion bout the bass if its still going on

 

[jerg]

Lol, anyone wanna try swapping on focus pads and see if the subbass rolloff is gone? I'm curious if it is a pad-related symptom.

 

[Tamirci]

   
Some folks are too enamoured of amps and the "magic" it can do.
 
I tried a test and LG G3 direct to HE-400S sound exactly the same as LG G3 to amp then HE-400S. So what does that tell us? Maybe it isn't the ability to drive that's the limiting factor.
 
As for roll off of this or that, well the measurement is what it is. Different folks will say different things no matter the measurement or alignment of the planets. You can find people who think the old school Beats are great if you look hard enough...
 
What I am saying is I don't think anyone can for 100% sure decide if they'd like this set without listening to it themselves. Personally, I trusted Tyll's hints about it from the trade show since everything he recommended has worked well for me. And this time is no exception. My initial objection to the treble has now dissipated after breaking in my ears a bit.

My answer is solely based upon idea on amping:
 
When connecting a device to an amp; it HAS to have a line out as the first rule. This out will bypass the mp3 player's inner (and meager in this case) amp. Otherwise the amp and the device's amp will try to strenghten the signal at the same time but fail.
But if you connect a device that has line out function, you can enjoy an amp's %100 potential. But remember the rule: A system will function according to it's worst component. Thus a powerful dap is a MUST for an amp to perform at best. 

 

[gotak]

My answer is solely based upon idea on amping:

When connecting a device to an amp; it HAS to have a line out as the first rule. This out will bypass the mp3 player's inner (and meager in this case) amp. Otherwise the amp and the device's amp will try to strenghten the signal at the same time but fail.
But if you connect a device that has line out function, you can enjoy an amp's %100 potential. But remember the rule: A system will function according to it's worst component. Thus a powerful dap is a MUST for an amp to perform at best. 

I really don't think you understand amplification....

 

[obsidyen]

Lol, anyone wanna try swapping on focus pads and see if the subbass rolloff is gone? I'm curious if it is a pad-related symptom.

I'm using them with Focus pads, I think the bass is better compared to regular pads. There's no way anyone could call these bass-shy. It hits really nicely and the impact is superb. Not HE560 level perhaps, but much better than the likes of HD650. Maybe it's the Focus pads that makes the bass better, someone should measure them with Focus pads. I wish Tyll did that as well.

 

[money4me247]

Lol, anyone wanna try swapping on focus pads and see if the subbass rolloff is gone? I'm curious if it is a pad-related symptom.

@jerg, I will be able to do this as I have the HE-560 with the production focus pads & a measurement rig. will update you guys with the findings.

 

[Tamirci]

I really don't think you understand amplification....

Then please explain me this:
 
I connect an ordinary mp3 player to an amp through its headphone output via mini to mini cable and I get a result.
Then I connect a line outted mp3 player (let's say qa360) to the same amp via the same cable but through it's line out and listen the same headphone.
 
Results had varied greatly. Qa showed both its power and amps power.
Ordinary one performed weak.
 
Amping is basically rising the vloltage you give to headphone. Any resistances in the path will reduce the result. 
What else in amping you think I don't undertand?

 

[obsidyen]

I really don't think you understand amplification....

He's saying that double amping will affect the sound negatively and that's true. Why do you think so many dacs and DAPs have line out? So that you can use any amp you like without double amping. You have no chance of doing that when you connect a phone's headphone jack to another amp. That's also why people prefer using digital (usb) connection to connect the phone/tablet to amp/dac rather than using the headphone jack. A line out or a digital connection is a must for pure signal transmission. This is audio class 101.

 

[Tamirci]

  He's saying that double amping will affect the sound negatively and that's true. Why do you think so many dacs and DAPs have line out? So that you can use any amp you like without double amping. You have no chance of doing that when you connect a phone's headphone jack to another amp. That's also why people prefer using digital (usb) connection to connect the phone/tablet to amp/dac rather than using the headphone jack. A line out or a digital connection is a must for pure signal transmission. This is audio class 101.

Yay!