[TopPop]

Quote:

Originally Posted by jaudio /img/forum/go_quote.gif The same with the 700's, much better with the felt ring off. What is the difference in the sound with acoustic lens off and on?. Does it look like you can adjust the offset?

I'm going to fiddle with this a bit tonight (or tomorrow), and report back. The felt ring is glued on, but I don't think that it would be difficult to make a new one and put it in if removing the ring ends up being detrimental to the sound.

The offset can't be adjusted on the acoustic lens, unless you want to find a way to set the ring (glue?) at a different angle than the screw holes allow.

I'm also curious about the three holes off to the side of the ring. Looks like they're covered with felt, too (but from the inside of the enclosure), and the center one has a small hole in the center. I haven't taken the whole thing apart yet, but these should be between the rear enclosure and your ear. I'm guessing that removing the felt might reduce some of the bass as well... or am I totally off on this? I don't remember how this works.

 

[TopPop]

Also, after thinking for awhile on this, I believe that some of the basic mods that markl has found to work well for the Denon d5000 would also benefit these uber-cheap headphones.

Specifically:
-Damping the backside of the cup with Dynamat
-Damping the inside of the cup with a thin layer of acoustic stuffing
-Damping the backside of the driver and basket with Dynamat

These mods should be easy and cheap(ish), and should help the overall bass response (the biggest flaw with these phones). In addition to removing the felt ring, I think that these mods will help realize the (presumed) potential lurking in these cans.

Thoughts? I'm not sure if many people are willing to start tearing these things apart yet, but I'm feeling unusually ambitious, so, unless someone else feels like taking the plunge first, I think I might go ahead and gather together the materials for these types of modification very soon, and post the results.

Some may think that this borders on the ridiculous, since these are relatively cheap headphones by comparison, and these mods probably won't make them any giant-killers... but mods are half the fun of this hobby, are they not?

 

[musicman59]

It's just me or these things sound on the dark/veiled side?
I did burn them in for over 200 hours with the IsoTeck CD but even after that I think the sound laks air and clarity.

I agree regarding the soundstage. it is big width wise but there is not much depth.

I think they are going to go to the market.....

 

[micmacmo]

Quote:

Originally Posted by musicman59 /img/forum/go_quote.gif I think they are going to go to the market.....

Before you do, could you comment on how the RX900 compare to the Denon D1001? They seem like popular alternatives in the sub-$100 category. And budget-fiers need to know!

 

[Alai]

Ok, so I tried to look it up, but I can't tell other than it is really popular for car audio... What the hell is Dynamat and how does it work?!

 

[Moontan13]

Quote:

Originally Posted by goober-george /img/forum/go_quote.gif Do you have any kind of MP3 player that you can use with your JVC HA-RX 900 to really appreciate the difference between amped and unamped?

Using an iPod 5.5 and 192k AAC files, there's a noticeable improvement with any amplification. Using them with an iPod without amplification still renders very good SQ. Not having an amp isn't a reason to put off getting these, IMO.

 

[kirimaru]

Quote:

Originally Posted by musicman59 /img/forum/go_quote.gif It's just me or these things sound on the dark/veiled side? I did burn them in for over 200 hours with the IsoTeck CD but even after that I think the sound laks air and clarity. I agree regarding the soundstage. it is big width wise but there is not much depth. I think they are going to go to the market.....

I think that the problem is that your system does not has synergy with rx900,you can try adjusting the trebel with equalizer.

 

[melmac]

Good review toppop!! Nice one!

 

[TopPop]

Quote:

Originally Posted by Alai /img/forum/go_quote.gif Ok, so I tried to look it up, but I can't tell other than it is really popular for car audio... What the hell is Dynamat and how does it work?!

Yeah, it's meant for car audio, but I've used it in just about anything you can think of for home audio!

It's a type of thin mat that's covered on one side with a very sticky tar-like substance. When heated or applied with enough pressure, it will adhere to the surface, and will damp mechanical resonances of whatever material it is placed on. Very handy for reducing mechanical resonance in CD players, amplifiers, DACs, speakers cabinets, drivers, headphones, etc.

The use for this mod is to reduce resonances in the headphone cup that may be either audible (i.e. a sort of dull ringing from the cup that muddies the sound), or may cause the driver to resonate at the same frequency (i.e. the driver produces a sound, which causes the headphone enclosure to vibrate, which, in turn, causes the driver to vibrate again at this resonance frequency). Both types of interference can, and do, affect the sound that ultimately reaches your ears.

 

[TopPop]

Quote:

Originally Posted by melmac /img/forum/go_quote.gif Good review toppop!! Nice one!

Thanks!

I'll order the modding materials soon, so I'll be back on this thread later with more impressions.

 

[melmac]

Well I have just got mine today and have never had such a good pair of headphones. Will be interested to hear how you get on with the modding and does it make much difference. Will have to make a lot of difference for me to rip apart the best headphones I ever owned lol.

 

[dclancy]

Quote:

Originally Posted by Alai /img/forum/go_quote.gif Ok, so I tried to look it up, but I can't tell other than it is really popular for car audio... What the hell is Dynamat and how does it work?!

Check out this Markl mod page, to see what he's referring to.
I'm not a huge fan of removing the felt ring, it actually came off cleanly if you peeled it slowly. I liked the hard hitting bass aspect of the 700's, of course if I wanted sweet mids, I'd slip into my AKG's.

 

[dclancy]

Quote:

Originally Posted by melmac /img/forum/go_quote.gif Will have to make a lot of difference for me to rip apart the best headphones I ever owned lol.

My own 2 cents. Enjoy them stock, then mod when you get bored and ready to upgrade anyway. You don't want to feel like a goof cause you got careless and pierced the diaphram trying to get more air between the driver and your ears.
If the 900's are as close to the 700's as I think they are, they're definitely is a peak performance point you'll hit here. You may be able to ripen a tomato but you'll never make it a kumquat.
By all means I'm looking forward to see what I here the Markl mods effect would have on these cans, but if they're your only set of nice phones, it may not be worth it. Have fun if you do!

 

[TopPop]

Well, I (and anyone reading this who actually cares!

) will have to wait a bit for my findings, since I'm cheap when it comes to stupid things like paying for shipping. I bought some Dynamat on Amazon, but since I was also preordering Wall-e for a Christmas gift, I was able to get the Super Saver free shipping... which means that the Dynamat won't get here until Wall-e is released and shipped.

Patience.

 

[TopPop]

Holy...

Impatience got the best of me, and I decided to do some quick mods that would at least give me an impression of what I should expect from the final mods.

As expected, the whole spectrum evened right out! Bass is no longer overpowering, but still deep. Midrange takes a jump forward. Treble is much extended (though still not extremely "airy"). Soundstage remains wide, and imaging seems to tighten even a bit more than before (perhaps due to the increase in midrange and treble information). Spatial cues are enhanced, which allows for a sense of a "blacker" background, if you will (that term seems to be thrown around a lot, unfortunately. I know what I mean by it, though; hopefully you will, too!), as well as enhancing soundstage placement.

These mods can be done fairly quickly, and with few tools/materials. The first step is to remove the ear pads. This can be done easily by pulling gently at the material that is inside the side of the headphones, all the way around, until you have the whole thing off. You will see the "acoustic lens" right away. Two screws, and it's off. Here's where the first mod comes in: if you gently scratch at the felt ring that's glued underneath the lens, the top layer will start to peel off. If you peel this layer off the whole surface, you are still left with a thin layer that covers the holes; I'd recommend leaving this on to help keep hairs and dust out, but do as you please. Screw the acoustic lens back on.

Next, there are three screws that are deep-set into the plastic around acoustic lens, nearer the edges. You'll need a fairly small philips screwdriver to get in there; not too small (like the kind made for eye glasses), but smaller than standard philips. Separate the two halves of the cup, being careful to not put strain on the tiny wire. All I did at this point was to put a couple of strips of foam tape on the inside of the cup, to help damp vibration. The foam tape won't do nearly as good of job as the Dynamat will (whenever it gets here), but it's better than nothing. The last tweak was to add a bit of acoustic stuffing in the cup before sealing it back together. The key words here are A BIT. Like markl mention in his original D5000 post, too much stuffing will kill the bass. I think that I may have put just a bit too much in, so be sure that you just put a very thin (~1/8" - 1/4") layer of stuffing inside.

That's it. Simple. If you can get some Dynamat, as I'm planning, it would be best to use that instead of foam tape. Also, the plastic housing is very flimsy, and I don't imagine that it would hurt to damp as much of it as possible on the inside. Plus, a small circle to cover the back of the driver magnet would be a must.

I'm going to redo these quick mods when the Dynamat comes, obviously, and will post pictures at that time.

Seriously, though, these headphones have a lot of potential, and I can imagine them competing very well with my more expensive phones for time on my noggin. If you're skeptical, give them a chance. Do these simple mods, and I assure you that these will be some of the finest headphones you can buy at this low price point. If you don't like them, you won't have any trouble selling them here!!

Enjoy!