JVC HA-RX900 Open Mod + More.

[LaPierre]

I'm a proud owner of the budget cans, JVC HA-RX900 and I'd like to tell you the story of how I took the simply 'a little better than average' in it's price range headphone and made it (in my opinion) drastically better. At first I was reading this lovely thread by TopPop http://www.head-fi.org/t/381303/jvc-ha-rx900-modifications-a-picture-tutorial-56k-forget-about-it on how to modify these JVCs and seriously desired to improve my JVCs because their highs are lacking and they have a slightly unnatural vibe to their sound. I searched around my local stores for dynamat and acoustic stuffing, but to no avail could not find them at all. So like the immature, antsy teenage boy I am I bought other materials I thought might be good for modding, which ended me up with modeling clay, a bag of cotton balls and some think felt sheets.
 
I opened up the JVCs and packed the cup with red and blue clay after removing the felt ring covering the drivers (each side respectively) and topped it with a layer of similarly colored felt (cut into pieces to fit the depressions and places I was putting it in) until I had a decently covered internal cup surface. I tried a quick comparison (right to unmodded left) and noticed an up in clarity and a more smooth sound in the modded side, bass was unchanged. I decided to add a layer of cotton in a few different thicknesses and it sounded to me like it was unnaturally skewing the sound for the worst and made the highs sound similar to how poorly compressed mp3s sound, --- and for some reason didn't effect the bass too much. Knowing that without the proper materials I could never achieve the same results as TopPop so in my last efforts I decided to do something a lot more extreme. Remove the cups a.k.a. openify the JVC HA-RX900.  
 
The RX900s design didn't make removing the cup an easy job... in fact, I handled it in an extremely brutal and unprofessional way. I took a utility knife and pried the metal plates off each side and twisted the knife into the plastic to create a lot of holes and continued to do so around the surface of the cup, inefficiently and ruggedly opening them up. Of course, halfway I compared them to the partially modded side that was still closed and the now opened side. They were the same in sound signature but the open side improved drastically without any downfalls, miraculously. The frequency response seems to have lost most of it's irregularities and awkward dips and spikes, and the bass seems to have went up a notch in both quantity and naturalness, the extension and quality doesn't seem to have changed much (if at all) but I've noticed it's slightly more impactful and quicker in general. Of course, now that it's open it's lost what little isolation it provided (really, it didn't block much to begin with) and at the same time leaks a lot more sound (which it didn't leak too bad to begin with). The soundstage is fairly large, definitely more than it started with without a doubt and one of the only flaws in it's sound is it's weaker imaging ability, --- which mostly is noticeable with less-than-bright vocal tracks (the lower midrange likes to blend) and I can't say I remember if this was a problem or not with the stock sound (probably), but it doesn't matter because I really love their new sound. At 50$ and less than 10$ in supplies mixed with a bit of effort their sound easily rivals headphones twice that price. (around and under 150) I can't comment on how well it fairs against other open headphones under 200$, but it's definitely still affordable enough for those curious enough to test it out.
 
Here's some pics of my ugly yet beautiful and highly loved JVC HA-RX900 v2:
 
 
 
 
 
 
Feel free to question, comment and even throw some advice at me regarding my experiment. I'm all ears and this may be the first but won't be the last DIY job I do. (I just hope this isn't a consistant quality of work )
 
 

 

[KetchupNinja]

Great idea, I like it!  Borrow a dremel and clean those up, maybe add a wire mesh guard and you'd be set!
 

 

[LaPierre]

Thanks! I already put some mesh on the cups temporarily and I plan to completely clean these up. If all fails I'll start fresh on a new pair of RX900s but it's totally worth it.

 

[LaPierre]

--note: I'm buying a new set of RX-900s to re-attempt this modification with proper tools and will thoroughly record my modifications and how I did them with pictures, explanations and everything; and will even try to dampen them with a few different materials.

 

[kramer5150]

SOLID...  I read through most of the original mod thread and it seemed like most were adding mass and acoustic damping materials.
 
Curious, how is the plastic earcup piece fastened to the perforated mesh?
 
**EDIT**
Looks like the mesh + plastic earcup piece are tab in slot bent into the earcup. 

 
 
Being that they are naturally bass-heavy, with some odd midrange resonance-colorations I probably would have opted to open them up like you did.  You did the hard part, now just get a dremel and grind everything smooth.  It probably wouldn't be hard to fabricate a cosmetic trim-ring out of wood, stain it all up pretty and cut a mesh screen using perforated sheet metal stock.  I did that a long time ago to my HF1 and it turned out to be my nicest looking headphone.
 

 
 

 
 

 

[LaPierre]

Your HF1s came out beautifully. I like the idea of a wood ring, something like that might just fit the RX-900s really well. I'm not sure why people think the RX-900s are bass heavy, they're really not. I'd say they have decent extension and a very small midrange bump, but aside from that they sound flat from the mid range down,--- and with that awful felt ring out of the way the highs aren't so recessed and they extend fairly well upwards. The cups work completely against the sound though, it's amazing how capable the drivers in such a cheap headphone are. JVC should seriously consider an open series of headphones. I bet an open version of the DX-1000s would sit very well with the audiophile crowd 

. But anyway, if you don't mind I'd like to know how exactly I'd go about making a wood ring and attaching it to the headphones in a non-shoddy/clean way? I'm thinking for the grille/mesh I can just glue it onto the cup from the inside. 

 

[kramer5150]

Quote:

Your HF1s came out beautifully. I like the idea of a wood ring, something like that might just fit the RX-900s really well. I'm not sure why people think the RX-900s are bass heavy, they're really not. I'd say they have decent extension and a very small midrange bump, but aside from that they sound flat from the mid range down,--- and with that awful felt ring out of the way the highs aren't so recessed and they extend fairly well upwards. The cups work completely against the sound though, it's amazing how capable the drivers in such a cheap headphone are. JVC should seriously consider an open series of headphones. I bet an open version of the DX-1000s would sit very well with the audiophile crowd 

. But anyway, if you don't mind I'd like to know how exactly I'd go about making a wood ring and attaching it to the headphones in a non-shoddy/clean way? I'm thinking for the grille/mesh I can just glue it onto the cup from the inside. 

Good sound starts with the driver.  If the driver is trash to begin with, then nothing else is going to save it.  A good driver in a "bad" earcup can be modded to surprisingly high standards too, as you have discovered.
 
In regards to wood fabrication... Wood selection and tool cutting stroke is key.  Some harder woods are hard/brittle with REALLY strong grain structures that are difficult and very labor intensive to work with.  Cutting/grinding against grain on these woods is difficult, but not impossible.  Rosewoods, mahogany come to mind immediately, and they are desired for their acoustic qualities.  At the extreme would be ebony, HARD, brittle and very $$$.  Korina is another timber prized for its acoustic tonal qualities.  Its also hard and difficult to work... and it contains carcenogenic chemicals, you do not want to breathe in its dust.
 
If you can find hardwood stock thats "sliced" cross grain, that would be ideal, since for the most part your cut strokes would be crossing the grain and not working against it. 
 
For the HF1 I modded, I used Bloodwood.  Not really noted as a "tone wood" (to borrow a term from guitar-fi).  I liked its red-ish color when oiled, so its purely a cosmetic thing.
 
For your case, being that the wood pieces would be more of a cosmetic trim ring.  I would stick with something thats easy to work with.  Poplar, basswood come to mind immediately.  They are actually good tone woods too, noted for their warm/bassy acoustic qualities in guitar making.  But they are easy to work with and they are porous and soak up stains very well.  A dark walnut stain on these woods with a tung oil on top is not a bad look at all.  Finding stock thats a "pure wood" color might be difficult.  I have seen a lot of basswood and poplar with green and dull-grey color tints.  A lot of kids toys are poplar... easy to work with.
 
Alder is another option, a bit harder and more pronounced grain structure than poplar / basswood.  But the reward is a nicely contrasting grain structure, and it shouldn't be hard finding alder stock thats not green or odd-colored.
 
With a headphone as BIG as the RX-900, you should be able to pull it off with a fine tooth jig-saw and hand tools.  A scroll saw would be ideal.
 
On that HF1 I used a drill press, hole cutters and a wood rasp bit.  God this was almost 10 years ago... fun walk down memory lane.
 

 
 

 
 

 
 

 
 

 

 

[LaPierre]

Thanks for the lengthy explanation, I really wouldn't have known where to start if you hadn't chimed in with your knowledge and past experiences. I'll take my time and hopefully my JVCs will come out half as good as your HF-1s. The JVCs are definitely big 

 all the better for amateur modding. If I'm successful I'm probably going to buy a pair of RX700s and open them up as well, I hear they have a more refined sound than the 900s yet they're in the same enclosure for the most part, sounds like they've got just as much potential.

 

[kramer5150]

Sure no prob.  Another material I think you should consider is Acetal (or Delrin).  its available in paintable white, black or gray.  Its a semi hard plastic like material thats easy to cut and grind.  It can be sanded smooth and painted too.  I used 3/8" stock to make the top cover LED light fixture for my fish tank... I'd go this route if you're not after the organic wood look.  I am not sure how well glues and epoxy adheres to it though.

 

[shimistauber]

hey did you ever add wood to you ha-rx900's? im looking to do the same and would love some tips.

 

[Murat]

Can I put another driver in these cups?