[retskrad]

I compared the hd650 and the he-400 (or any planar magnetic headphone) and holy moly I was shocked. The planar headphone sounded like it puts out the entire bass frequency range without a problem at all.  At the same time you can hear sub bass, mid bass and lower mid range frequencies at the same time, you can dissect it and it sounds so clean and effortless. They sound like a speaker from far away.
 
The hd650 (and other dynamic headphones for the matter) was only able to put out mid bass and the rest was quite as hell, or you barely heard it. I need to lower the mid bass to hear the sub bass. They struggled  when putting on a lot of bass layers.
 
So guys, how is the difference in bass so big?

 

[jcx]

is it? - how did you compare? what SPL? (matched to be the same with each headphone, right?)
 
you could read Tyll's InnerFidelity posts on how he measures, the article on headphone graph reproducibility - basically frequency response graphs are pretty good, reproducible below a few kHz
 
so if your impressions vary from what the graphs indicate then you need to figure out the issues - perceptual (Fletcher-Munson, "perceptual anchor" frequency band), physical (sealing, positioning on the head)
 
unfortunately Blinding is going to be hard with the differing weight, pads clamping pressure so you probably need to train extensively on identifying EQ by band, dB of cut/boost

 

[castleofargh]

  I compared the hd650 and the he-400 (or any planar magnetic headphone) and holy moly I was shocked. The planar headphone sounded like it puts out the entire bass frequency range without a problem at all.  At the same time you can hear sub bass, mid bass and lower mid range frequencies at the same time, you can dissect it and it sounds so clean and effortless. They sound like a speaker from far away.
 
The hd650 (and other dynamic headphones for the matter) was only able to put out mid bass and the rest was quite as hell, or you barely heard it. I need to lower the mid bass to hear the sub bass. They struggled  when putting on a lot of bass layers.
 
So guys, how is the difference in bass so big?

were you expecting the hd650 to have flat bass and sub bass? I would suggest to try and get about the same signature first(by EQ or with another headphone), at least in the area you're talking about.  then maybe you'll be able to check bass differences from the type of driver.

 

[Pirakaphile]

Cause the driver is so much larger, I would expect. Since it's so massive, it can reproduce the lowest sounds more easily due to the amount of air it's moving. Most headphone drivers can move at really slow speeds, just they can't move as much air at that low speed so you can't hear it as well I guess. All speculative, but subwoofers tend to be much larger than just woofers, and it's because they need more air movement to get the lower bass notes, since they're larger waves. If you put a six inch woofer cone right up to your ear, you could probably hear a lot lower into the bass notes just cause it's right in your face instead of on the other side of a room. It can hit those notes, just can't push the air with the superiority of a twelve inch subwoofer.

 

[retskrad]

So the fact that planar magnetic headphones are so flat in the bass to lower mids because the driver is so big, and that creates "a wall of sound" which doesnt have a cone-like sound wave, while the dynamic driver sound waves are more cone like, thats why the mid bass are so apparant?

 

[SilverEars]

  Cause the driver is so much larger, I would expect. Since it's so massive, it can reproduce the lowest sounds more easily due to the amount of air it's moving. Most headphone drivers can move at really slow speeds, just they can't move as much air at that low speed so you can't hear it as well I guess. All speculative, but subwoofers tend to be much larger than just woofers, and it's because they need more air movement to get the lower bass notes, since they're larger waves. If you put a six inch woofer cone right up to your ear, you could probably hear a lot lower into the bass notes just cause it's right in your face instead of on the other side of a room. It can hit those notes, just can't push the air with the superiority of a twelve inch subwoofer.

You should check out FR of iems.  Flatter in the bass region than the rounded roll-off on dynamics.  Full sized dynamics and planars have roll-off at the very low frequency to some degree.
 
I thought the SE846's filter was quite interesting.  The FR inclines upward as you go low with good sub bass.
 
"Without the ability to add active circuitry, Shure had to resort to the most mechanical of filters. By welding 10 stainless steel plates together, Shure is able to carve out a four-inch long tunnel attached to the output of the low frequency driver. This essentially traps the shorter wavelengths of the unwanted mid-range frequencies and starts to rolloff the low end response above 75Hz, giving you plenty of bass and clear mid range."
 

 

[Pirakaphile]

  You should check out FR of iems.  Flatter in the bass region than the rounded roll-off on dynamics.  Full sized dynamics and planars have roll-off at the very low frequency to some degree.
 
I thought the SE846's filter was quite interesting.  The FR inclines upward as you go low with good sub bass.
 
"Without the ability to add active circuitry, Shure had to resort to the most mechanical of filters. By welding 10 stainless steel plates together, Shure is able to carve out a four-inch long tunnel attached to the output of the low frequency driver. This essentially traps the shorter wavelengths of the unwanted mid-range frequencies and starts to rolloff the low end response above 75Hz, giving you plenty of bass and clear mid range."
 

The drivers are so small, and only need to move a tiny amount of air when they're inside your ear canal, so it's just common sense to me that well built IEMs can have a very solid bass response. However, I tend to like full size headphones over IEMs, unless I'm on the go.  

 

[castleofargh]

  So the fact that planar magnetic headphones are so flat in the bass to lower mids because the driver is so big, and that creates "a wall of sound" which doesnt have a cone-like sound wave, while the dynamic driver sound waves are more cone like, thats why the mid bass are so apparant?

not really. obviously having bigger driver makes the job easier for bass, but that has nothing to do with the kind of driver, it's just a physical reality.
  now as far as techs are involved, planar actually struggles more than dynamic to go loud in the sub bass region. they need big ass power to do so.