[micmacmo]

Hey, leeperry, in post 33 of this thread, I discussed some of the things I learned about sound deadeners like Dynamat Original and Dynamat Extreme and how they are intended to work.

 

[leeperry]

right, but for the back of the driver I really don't think that aluminium will do any good..

 

[notuagain]

Ok for those interested here's what I have completed:

1. Removed sticky felt completely from driver cover, including holes directly above driver. Very tedious and tricky...but worth it. Please take care as the driver is very close to plastic cover and contact is easily made.

2. Placed some circular felt pads on the back of the drivers that were approximately the same diameter. Easy, once open. As TopPop stipulated be very careful with the driver connecting wires, SO delicate looking.

3. As an experiment I decided to try some steel wool as a filling behind the driver, as I thought other types of fill would add to damping the top end. There is no direct contact with the driver as it is covered by the felt pad I placed. This is entirely an experiment as I'm not sure how a magnetic driver will react with a metal based fill, but for now all seems well. Might be worth considering a layer of tissue paper between driver and steel wool fill to add a layer of protective seal, to completely avoid contact.

4. Completely removed acoustic lens.

The result is almost everything I was looking for. The topend is now coming from a different headphone, so detailed and airy with a nice metallic edge to it.

Soundstage has narrowed slightly but that was huge to begin with, so still very nice.

Instrument and sound placement has become more defined and the mids are somewhat clearer.

Bass has mellowed alot (could be steel wool filling) so if your main use of these headphones is for bass, I would not recommend these type of mods/materials.

Echo and resonance has been tamed.

I had a close look at the cable and it looks like fine, non-isolated, copper covered steel.

Overall well worth the effort.

 

[jageur272]

Interesting... Instead of circular felt pads, most people use Dynamat in order to dampen the drivers themselves. This should clean up some of the residual buzz from the drivers vibrating over the wrong axis (X as opposed to Y, which would be normal to the driver face).

Any sort of filling behind the driver will decrease bass, thus creating a brighter sound. Steel wool will interfere terribly with the sound, you try to get the finest stuff possible (fiberloft imo) in order to maintain acoustic transparency. Also, distancing your ear from the driver should result in a better soundstage

 

[notuagain]

Quote:

Originally Posted by jageur272 /img/forum/go_quote.gif Interesting... Instead of circular felt pads, most people use Dynamat in order to dampen the drivers themselves. This should clean up some of the residual buzz from the drivers vibrating over the wrong axis (X as opposed to Y, which would be normal to the driver face).

I agree Dynamat is a better choice, but I couldn't obtain any and the felt pads I have used are very dense and solid.

Quote:

Originally Posted by jageur272 /img/forum/go_quote.gif Any sort of filling behind the driver will decrease bass, thus creating a brighter sound. Steel wool will interfere terribly with the sound, you try to get the finest stuff possible (fiberloft imo) in order to maintain acoustic transparency. Also, distancing your ear from the driver should result in a better soundstage

I agree with your theory steel wool (I used a very fine layer) would be a disaster in most scenarios, but the top end of the RX900 is so backward and lacking, I thought I would experiment and just test the result. From what I can initially hear it certainly benefits the sound compared to no fill and am actually impressed with the outcome. I will compare it with a more traditional fill in the future, but for the moment I'm content with the sound.

 

[leeperry]

if you look at the DynaXorb shape, the best solution seems to be something that absorbs sound and not flat...the more bumpy, the more reflections will be "broken"

like the usual acoustic dampening

wood is good coz it doesn't vibrate but it sends very "natural"/"organic" reflections...when markl adds dynamat extreme in his D5000 mod, it prolly renders the upper spectrum quite harsh(counterbalanced by the OFC cable?

)

I'll show you what I used to dampen my 770, it's irregular and "sounds" great to me...I was thinking about changing it for acoustic cork(the thinner, the more it kills trebles from some scientific tests I found on google), maybe maybe not...like recabling w/ SPC, not quite made up my mind yet

 

[leeperry]

some ppl crave for harsh/metallic trebles apparently : http://www.head-fi.org/forums/f4/jvc...00-mod-391515/

and this is what I used to dampen the cups, now I let you guess what it is

 

[notuagain]

Wow a quarter behind a $1000 headphone! The irony

Seeing that thread makes me feel the steel wool is a good solution for the 900's top end issues and if you are skeptical, try it, you might be as pleasantly surprised as I am. It really has altered these phones into a very well balanced pair cans.

Next up is the recable.

As for you damping material leeperry, are all the pictures of the same product?

Looks like hessian in one picture and some kind of hemp in others? Dunno.

 

[leeperry]

there's plenty of room in that JVC DX1k, some rubber(dynamat original?) dampening would do wonders I think.

yes, they're all the same material

I hardly have a few millimeters behind the drivers, there's no chance I could stuff it w/ steel wool(which shouldn't sound much different from acoustic stuffing I think)

anyone else able to guess what my dampening is? it took me a while to think about using this, and it sounds perfect to my ears in the 770!

in the meantime, I've added foam at the back of the ear pads to angle the drivers(a la R10/cd3k)...it's very impressive now! the sound comes from the front, fantastic soundstage

 

[1Time]

Steel wool... is this the 0000 variety?

 

[notuagain]

Quote:

Originally Posted by 1Time /img/forum/go_quote.gif Steel wool... is this the 0000 variety?

Hi,

I didn't know there were different types or grades of steel wool, but after looking at some pictures I think the type I used is coarser than 0000.

Finer steel wool could be an even better solution than I use.

 

[Evshrug]

Hello, sorry to dig a dead thread, but Just Wanted People to Know... I bought TopPop's RX900 from him, and this "historic" modded RX900 has been given to a music major as a graduation present. It's his first entry into Hi-Fi. We'll be doing a joint review as soon as we both have time!

 

[Ericular]

I am not good at discerning tiny differences between headphones. I liked the sound of my new rx700s, but since finding the highly regarded DT770s sibilant, I was a little worried that this mod would give me harsh highs. Curious, I removed the felt ring and got the pads all snug back in place.

OK, let's plug them back in. Cue up the last song I was listening to... hit play... WOW... These sound unbelievable now. Before they were darn good headphones for the price, and now they're amazing headphones for the price. Crisper, more present highs with no sibilance anywhere in sight. I've got a pair of rx900s arriving this week, so I look forward to modding those as well.

Thanks for the great photo tutorial. The rx700 not having an acoustic lens had me puzzled for a few seconds, but made it even easier to get at the felt ring. I didn't try any cup stuffing, but perhaps I will later on. Will the Dynamat / stuffing take away from the bass? Coming from Senn HD 212's, everything sounds like it's lacking in bass -- but my brain should adjust soon enough... I just wouldn't want these rx700s to lose much bass.

 

[notuagain]

If you've got a pair of RX900s arriving next week, don't worry, your 'bass-ship' will be arriving soon.

Well worth completing TopPop's mods.

 

[Ericular]

My RX900s arrived today. After experiencing the felt mod improvements on the RX700s, I was eager to try it out with these. First side went fine -- on the other side, the acoustic lens seemed slightly stuck to the felt, and in that small spot both the layers of felt started to come off, leaving the bare plastic. I carefully separated the two layers and all was well.

I figured as long as I had them open, and an old stuffed animal laying around, I'd try a little cup filling. On my first try, I put in what I thought was a small amount, but that really killed the bass. I tried again, leaving a very thin layer. It's easy to see the cup through the fibers. It's little enough that it doesn't seem like it will do much of anything... but to my ears it sounded perfect. I enjoy the 900s stronger bass, and the slightest amount of fiber seems to have taken the boomy edge off.

This is all with < 1 hour of burn in time, so hopefully the sound will mature even more.

For those who believe in burn-in (which most seem to with the 900s), how did the sound evolve for you over the first 100 hours?