[fjrabon]

So, there was some talk about this in the HE400i thread, but I thought I'd give this its own thread so it doesn't get drowned out, and is a pretty major thing that didn't seem to be talked about at all.
 
Me and a couple of HE400i owners recently noticed that the insides of our headphones looked DRAMATICALLY different.  Like not "this is a different guage wire", like "missing an entire piece that seems pretty integral."
 
Here's the picture of mine:
 


I'd post some pictures of what the HE400i has looked like since its release, but I am not sure about the forum's rules about posting pictures I don't have rights to, so hopefully some other HE400i owner with the older (or correct?) design posts theirs, so you can see the dramatic difference.
 
The backplate is gone.  The big plate that covers the entirety of the magnet structure that has circular holes in it.  The backplate is the single most easily noticeable part of the structure and it's just gone.
 
No backplate isn't unprecedented, the HE400s doesn't have a backplate.  And this looks a LOT like a HE400s driver because of that.  I've never had this confirmed, but I believe the HE400s has the backplate removed because the HE400s's magnets aren't as strong, and thus don't need the backplate to keep them stable.  
 
The backplate on planar magnetic headphones has always been a necessary evil.  The magnets were so powerful that they required a piece of metal to hold them in place because they exert so much force on the diaphragm.  The backplate isn't actually a sound generating aspect of the headphone though, it's there for structural stability.  
 
Again, the backplate has always been a bit of a necessary evil.  It's the primary culprit for the "closed in" feeling that planars are notorious for.  On the more refined models, great lengths have been taken to have it take up as little of the "pass through" area as possible, while still being able to add the integrity that is needed to the structure, given the strength of the magnets.  The HE560, for example, has gone through great lengths and lots of structural design to open up their sound.
 
The HE400s hit the tradeoff point.  Its magnets aren't as strong, somewhat befitting it's lower rung on the HiFIMan totem pole, but this did allow the benefit of no backplate, which made them feel much more open than you might think.  The combination of no backplate and weaker magnets has lead many people to think of the HE400s as almost a hybrid of a dynamic and planar headphone.  You got some of the openness of a dymanic, but also some of the rolled off sub bass of a dynamic too (due to the weaker magnets).  It was also much easier to drive and much more efficient than other HiFiMan headphones due to its weaker magnets.  It's an interesting, and compelling compromise.
 
Now, previously (or maybe still currently), the HE400i used a backplate, because its magnets were much stronger than the HE400s.  In fact the HE400i's backplate looked exactly like the backplate on the old HE400(no letter).  
 
But a couple of people who bought the HE400i during the black friday sale recently noticed that their drivers looked like my picture above.  No backplate.  In my mind, there are a couple of possible answers to this interesting fact:
 
1) HiFiMan, in the rush of orders that the insane black friday $299 sale caused (seriously, that was such a crazy deal), accidentally put a few HE400s drivers into some HE400i units.
2) HiFIMan, as they are somewhat known for doing have made a revision to the HE400i, deciding that the magnets don't need a backplate, and used the HE400s driver mount to hold the HE400i driver, and gaining the sonic benefits of no backplate
3) it's some sort of hyrbid of the HE400s and HE400i driver.
 
I think I'm leaning towards  #2 because given the HE400s's efficiency ratings, and comparing the volume I get out of my HE400i to other my efficient headphones, there's no way my headphone is even as close to as efficient as HiFiMan's stated efficiency measurements for the HE400s.  The HE400s measures as slightly more efficient than my Fostex THX00, and the THX00 is very noticeably more efficient than my HE400i.  It's a pretty dramatic difference.  So, I can't imagine that this is the HE400s driver.  
 
It's interesting, because I've always felt that people overblew the "closed in" feeling of the HE400i.  This would make sense, since I am missing the backplate, which blocks and reflects way more sound than a grill mod ever could in a million years.  
 
Interested to get some other HE400i owners' input.  
 
I love HiFiMan as a company, I really do, but any of these possibilities are soooooo HiFiMan.  Wouldn't surprise me at all if this was a new driver they didn't announce, if they just mixed up HE400s drivers, or if they put the HE400i driver in the HE400s style driver mount and just didn't tell anybody about the change.  
 
Regardless of what it ends up being, I love the way it sounds, I just wanted to put as much info as I had out there on it, and see what others thought.

 

[mysticstryk]

Will have to check mine later. I'd say that a quiet revision is probably the likely scenario.

Hifiman has some QC issues from time to time, but actually doing something as crazy as putting the wrong driver in a handfull of headphones seems like a stretch.

(At least, I hope so...)

 

[bavinck]

I'll get a pic of mine up too later today. This is kinda funny

 

[fjrabon]

Will have to check mine later. I'd say that a quiet revision is probably the likely scenario.

Hifiman has some QC issues from time to time, but actually doing something as crazy as putting the wrong driver in a handfull of headphones seems like a stretch.

(At least, I hope so...)

right, it's something HiFiMan has done before.  It would also maybe make the black friday sale make sense, as perhaps they were trying to clear out the old versions.  Then perhaps they sold more than anticipated, and had to release some of the newer versions during the sale.  I got mine direct from HiFiMan, and they sent me an email to notify me that mine would take a bit longer, because they had sold out of all their back stock, and it would be fresh off the line.
 
And yeah, I wish I knew somebody in the Atlanta area who owned a 400s, but, again, this isn't even in the ballpark of being as efficient as the the 400s's claimed efficiency, so I think that rules out using a 400s driver.  Different pads and different cups don't effect efficiency THAT much, I don't think.

 

[mysticstryk]

right, it's something HiFiMan has done before.  It would also maybe make the black friday sale make sense, as perhaps they were trying to clear out the old versions.  Then perhaps they sold more than anticipated, and had to release some of the newer versions during the sale.  I got mine direct from HiFiMan, and they sent me an email to notify me that mine would take a bit longer, because they had sold out of all their back stock, and it would be fresh off the line.

And yeah, I wish I knew somebody in the Atlanta area who owned a 400s, but, again, this isn't even in the ballpark of being as efficient as the the 400s's claimed efficiency, so I think that rules out using a 400s driver.  Different pads and different cups don't effect efficiency THAT much, I don't think.

Could they have made the change when they moved to the standard 2.5 connectors instead of the smc? Do we have any pics of 2.5 connector versions that still have the backplate?

 

[fjrabon]

Could they have made the change when they moved to the standard 2.5 connectors instead of the smc? Do we have any pics of 2.5 connector versions that still have the backplate?

this is my thought as well, but have only seen a couple of pictures.  Part of why I started this thread.  Weird that they made a big deal of the connectors, but, you know, didn't even mention probably the single largest sonic change you can make on a planar  other than the actual driver.  This is like the grill mod X100000 in sonic impact, haha.

 

[ChesterYonany]

i have the old connector (SMC) and mine looks like this:
 
 

 
 
took the picture from google.

 

[fjrabon]

  i have the old connector (SMC) and mine looks like this:
 
 

 
 
took the picture from google.

yeah, so looks like the exact same 7 magnet array (magnets are underneath the back plate between the rows of circular cutouts), even the same plastic mount.  Mine just doesn't have the backplate.  Also in the process of researching this I realized the HE560 has a 9 magnet array.  The HE400s and HE400i both have 7 magnet arrays.  
 
All I can think is that when they started making the 400i, they decided to play it safe and use a backing plate, but as they had more time to test it, they realized the 7 magnet array, even on the stronger magnet HE400i, didn't need a backplate.  My headphone is also about 8-10 grams lighter than the stated weight of the HE400i as well.  

 

[allsumnull]

I got mine in the cyber monday sale and they have the 2.5mm connectors and no backing plate on the driver. I don't find the soundstage that open but I have come from akg q-701's and my stereo rig is SET amp and horns so I'm used to *big* soundstage. I'd say it's a revision. It may also be connected to the static buzzing problems some posters have noted. The extra two magnets in the 560 is an interesting issue - I would have thought it would lead to greater sensitivity and a more closed in sound, but it seems the opposite is true (I haven't heard the 560's) - are the 560's magnets more narrow?

 

[fjrabon]

  I got mine in the cyber monday sale and they have the 2.5mm connectors and no backing plate on the driver. I don't find the soundstage that open but I have come from akg q-701's and my stereo rig is SET amp and horns so I'm used to *big* soundstage. I'd say it's a revision. It may also be connected to the static buzzing problems some posters have noted. The extra two magnets in the 560 is an interesting issue - I would have thought it would lead to greater sensitivity and a more closed in sound, but it seems the opposite is true (I haven't heard the 560's) - are the 560's magnets more narrow?

They seem narrower in the HE560.  I think the idea is that the magnets are more powerful as an array, though each individual magnet is slightly less powerful, and the magnetic force is more evenly spread out across the whole of the diaphragm, giving them a touch more refined sound.  The HE560 backing plate is also better engineered, so that there's more "pass through" space than the "old" HE400i backplate.  
 
I *think* that the more powerful the magnets are in a planar design, the harder they are to drive.  I suppose the more powerful magnets take more energy to activate, but am talking out my behind in that regard.
 
Also, yes, the HE400i won't compete with the openness of the Q701.  They aren't as open as my AD700, or even my HD650 was.  But they don't sound nearly as closed to my ears as some of the early reviews of the HE400i, which said they sounded almost like a closed headphone.

 

[fjrabon]

so I was reading over the headphonics review of the HE400s, and this quote about the soundstage caught my attention:
 
"
Wow, Hifiman has really upgraded the sound stage experience. There is no doubt this is the most spacious Hifiman to date (excluding the HE1000). I’ve owned every Hifiman over ear except the 400i and I can safely say it is not only the most mid forward, but also the vastest sounding. It has a great center image presentation, which was always a problem for Hifiman in the past. In my opinion, at least, all past models had issues with imaging and required a crossfeed EQ to be enabled to obtain a more complete imaging experience, Hifiman was always kind of “stereo left, stereo right” to me, maybe I am in the minority on that?
 
The experience doesn’t extend far left and right, but what is now offered is an improved, more well formed imaging experience as a whole. To me, the original HE-series weren’t passable with stereo width factor, but now and on the HE400S I can consider it acceptable and enjoyable as well. Depth of field is noticeably improved over the HE400 and there is certainly a darker feel to the backdrop as well.
I actually thought the HE400S soundstage was well above average and not what I was expecting at all. It has got a great sense of airy spaciousness particularly in the midrange. Imaging, whilst not a huge strength, is certainly more three dimensional than the PM-3 from Oppo. Mike is correct this is not a left and right experience but there is, however, good width. Height and depth for me though are a bit more curtailed. The roll off on the sub bass limited any sense of real depth in the sound stage compared to the HE400i. The treble height, though much better, didn’t quite have that airy articulation you would find in say the HD600. That full sounding mid-bass response though keeps things rumbling along at an acceptable pace."
 
That's more or less exactly how I would describe my HE400i's soundstage, except with better depth (because of less sub bass roll-off).  So, perhaps this was a move to address the one sound quality complaint people had about the HE400i, the lack of soundstage.  If it was the back plate that was killing the soundstage size all along, then maybe this "fixed" that? This doesn't have quite the soundstage that my HD650 did, or my AD700 does, but the soundstage on it beats a LOT of open headphones I've heard over the years, and every closed headphone I've ever heard. Based on auditory memory it beats the DT990, which has a pretty average large soundstage for a dynamic open headphone.  
 
I'd be very interested if anybody has bought any of these from HiFiMan since the black friday sale ended, and whether or not this is a permanent change.
 

 

[TMRaven]

Makes sense.  With only a single ended magnetic array, there isn't as much force pushing against them.  Epoxy alone is strong enough to hold them in place.  Not only should it improve spaciousness, but reduce weight a little bit as well.

 

[fjrabon]

  Makes sense.  With only a single ended magnetic array, there isn't as much force pushing against them.  Epoxy alone is strong enough to hold them in place.  Not only should it improve spaciousness, but reduce weight a little bit as well.

yeah, mine are about 10 grams less than the stated weight of the HE400i, but about 10 grams more than the HE400s.  Guessing that means that 10g of the weight difference between the two went to the HE400s using cheaper plastic and a plastic grill instead of the 400i's metal grill, while 10g were in the back plate of the 400i.

 

[ChesterYonany]

im looking for people in my area with the new 400i to see if we can do some A-B testing and find out if there is any difference.
but i doubt i will find one.
 
you people should try the same so we can know for sure

 

[Peapod]

Here's the picture of mine:
 

 
Mine -- with the 2.5mm connectors bought on the Black Friday deal -- looks like yours. Not sure how you get the plate off to show it like you did though.