[inertianinja]

I'm developing a mod for the HE-500 that would allow easy, non-destructive conversion to closed-back using 3D printing.
If this works out, I believe it would fit Hifiman's other cans as well.
 
Pictured below is the current version (black) and several prior iterations (white). Finish is a little rough right now, but they're fresh off the printer. 
 
Some Details:
- They are held in by friction alone, no need to glue or screw. At first I attempted to emulate the design of the stock retainer clip, but I found that I could get them to print accurately enough to be held by friction. They're easy enough to swap that you can do it while you're wearing the headphones.
- They're light and rigid - 27g @ 15% density; I could go up to 100%/49g, but I don't think it's necessary.
- For the inside of the cup, I started with a flat cup 15mm deep. This evolved to the current design (pictured in black), which has a spherical/concave cup 20mm deep and a nice heavily chamfered outside edge.
 
I'm hitting some challenges with respect to sound, though, which makes me feel like it's a good time to stop and see if anyone has any feedback. 
I assume the HE500 is tuned to be open, so I'll have some learning/experimenting to do if I want to make them sound good. 
 
 
Two problems:
(1) Bass - I had to add ports, or bass disappeared. Started by just punching a hole with a screwdriver; the current version has 3 smaller ports that could be plugged for customization of the sound. 
(2) Treble - very harsh. Not sibilant, just very forward. So far I have experimented a bit with adding cotton on the interior, but it's still way harsher than that of the open-back HE500.
 
 
So, what do you think?
 
Any suggestions for tweaks? 
 
Wishlist for features?
 

 

[wooo headphones]

Curious about what your goals are. Like what are you trying to achieve? Do you want to try and keep the same sound but with increased sound isolation / reduced leakage? Or are you attempting to increase bass? Etc.

 

[inertianinja]

  Curious about what your goals are. Like what are you trying to achieve? Do you want to try and keep the same sound but with increased sound isolation / reduced leakage? Or are you attempting to increase bass? Etc.

 
Either, or both. Just the ability to customize.
 
So often you see people searching for headphones like "I like X, but I'm looking for a little more bass" or "better isolation". If I can get these sounding right, maybe they could be tuned for different preferences. Semi-open, etc.
 
Or, for example, I saw a review of the ZMF Vibro that was titled "Closed-back for fans of the HE-500." Well, what if i could make the HE-500 closed-back and achieve the same result?

 

[RenZixx]

Huh I'm interested, thinking of closing up a hf580. How about adding some foam in the front or at the back (against the cups)

 

[bagwell359]

You might want to try the fuzzor mod. It will cut IM in the mids & treble which will help some of your problem.

You'll need a lot of batting and felt in there including front facing since its got two sided output. Something like a HE-400 would be easier.

The only high endish closed headphone I don't dislike is the MrSpeakers Ether 1.1, maybe if you get your hands on that you can learn a few things to help your effort.

I'd like to hear yours, I'm an unabashed fan of the 500 and a devotee of a very open version, if you can get me to like the, you'd have something!

Good luck.