Fostex T50RP Incremental Mods and Measurements
Dec 14, 2015 at 5:19 PM Post #1,996 of 2,870
  Just got a pair of these about a week ago and have started modding them. So far, I am very impressed. However, I still have a feeling that they can be improved with some of the slight grain/distortion and sibilant sound. They already sound better than most of my headphones that cost 3-4 times as much. Not sure how realistic it is to expect to improve them even more, but I have a couple questions to see what some of you guys that have more experience with them think.
 
What I have done so far:
* loaded the baffles with modeling clay
* put dynamat in the cups
* put adhesive felt over the dynamat (used what I had on hand)
* sealed the cup vents
* experimented with cotton and foam filling the cups, decided I like them better with none
* Felt with 4 holes in the corners punched out over the rear of the driver
* dynamat and felt over the ear side of the baffle
* 2 pieces of felt over the ear side of the driver to reduce sibilant sound
* I'm using SRH840 pads
 
Do you think that using the silverstone acoustic foam in the ladder shape instead of adhesive felt over the dynamat in the cups will help with the small amount of grain/distortion? Any other ideas that might help with the sibilance? The felt on the driver side helped a lot so far.
 
Thanks in advance for any help or suggestions.

 
 
Dynamat, Silverstone foam, and other sound proofing things, all they do is stop reflections coming off the inside of the cup back to the ear.

Some argue that the ladder shape will help break up echoes. Something like why studio foam boards are egg carton or triangles.


I'm not sure about distortion, but to my understanding 99% of these mods done, only enable the driver to sound as best it can. Ie: stopping echoes, damping the air so it doesn't go out of control. But a t50rp driver sounds like a t50rp driver. I'm guessing things like distortion are flaws with a cheap orthro. There isn't really a magic peice of felt you can stick on to reduce distortion

Again I'm guessing at this point, I'm don't know enough to say that is correct or not. BMF might be the guy to ask with all his experience with measurements.

 
 
I think we are limited only by the inherent constraints of the T50RP drivers' sound quality potential X the creativity of our modification configurations. The rest is up to experimentation and psychoacoustics.
 
beerchug.gif

 
Dec 15, 2015 at 5:23 AM Post #1,997 of 2,870
   
 
Tell me about it. A few days ago I went to a small woodworking company in my town that offers CNC wood machining services. I gave them a CAD file of a design for a wooden earcup, really simple design actually, could probably make it by hand if I took some time, but can't be arsed, and all they needed was a small 10x10x3 cm size block of wood.  They said that cutting one piece out of walnut will cost roughly 150 euros PLUS taxes. I turned and left without saying bye.  It's not like you're doing any work, all you do is plug a freaking USB stick into the machine, run the program and stand next to it for 10 minutes while it cuts it. I mean, 150 euros for a piece of wood that costs 3-4 euros if you buy it raw in any wood shop is overkill even if they would carve it by hand and it took 2-3 hours to do. I think some of these companies that do these services are abusing the fact that people don't have CNC machines in their favor, and are charging as much as they possibly can, I guess it's better to have high profit margins and do small amounts of work instead of doing a lot of work with small profit margins...keeps the machines in shape for longer and expenses lower. 
 
And this is the biggest problem. I have a folder with loads of designs and ideas that I'd like to build, earcups, headbands, entire finished headphone designs, down to the final screw. But it's just way, way, way too expensive until I buy my own 3D printer and CNC router. Once I have that I'll probably be able to make parts for and build 3-4 headphones a day. For now, it's pretty much impossible, or as you said, it's better to just buy a high end headphone than to waste money on projects.  Good thing I at least found a local 3D print guy who is reasonable with prices.
 
 
 
I also thought about rotating the driver upwards, as I noticed that I usually get an effect of sound coming from slightly above with most headphones, but the problem is if I twist the baffle too much, I might end up with a design that's hard to 3D print, even some simpler baffle designs that I had 3D printed so far were slightly twisted around the thinner parts, that's why I try to keep the designs for printing simple.
 
Oh yea and I know that HD800 driver DIY thread, that's actually a nice job too, but a bit expensive IMHO, I'd rather just get the HD800's instead of spending the same money for the DIY one that definitely won't end up sounding as good, because the HD800 is just too well engineered. But it reminds me of my old idea.... this is back from the time when I got my Beyerdynamic T1's and wanted the HD800's too but couldn't afford both, so I had this vision of a Beyerheiser T800 of whatever you wanna call it,  which would basically be similar to a HD800, fully opened, using either the HD800 drivers or T1 drivers, and it would be the right size for T1 earpads and headband.
Should have been made out of a 3D printed baffle and a anodized aluminium red decorative/strengthening part around it.
 

 
I think it looks cool but it would probably cost more to make than buying the new Orpheus. :p

Hi, I'm the guy who created the 3D printed headphones with HD800 driver, and I think I had more fun modding the headphones than just buying the HD800. The thing with DIY headphones is that you are trying to be Frankenstein, you want your phone to have the image and soundstage like the HD800, with closed design and lush  and emotional sounding and closed like the R10. That's the idea, but the result can be totally different, and you end up with a special product anyway, sounds nothing the same as the headphones on sale. Regarding the cost, the HD800 driver cost more than $350, my printer cost $600. add in connector, cables, printing filament, you end up around $200 more expensive than the HD800 as new. But with the 3D printer, you have much more projects to play with. You can always buy cheaper driver on aliexpress, the silk driver is pretty good. Also they have titanium plated, gold plated, carbon fiber driver for you to try. All are possible with 3d printing projects
Frank
Frank
 
Dec 17, 2015 at 7:37 PM Post #2,000 of 2,870

 
Be prepared for loose, boomy bass and midrange bloat.
 
I've come close (with a lot of modding trials) but I've never been able to approach the modded sound quality of drivers with the white material intact after going "naked."  ...and it's irreversible.
 
I hope you succeed where I've failed.
 
Dec 18, 2015 at 11:57 AM Post #2,001 of 2,870
I've had my T50rp's for about two years now and love them to death. They are based on BMF mods with a few tweaks. I've always wanted to had bamboo or wooden earcups but the lack of tools (lathe, etc, etc) has prevent the dream. Recently I saw these and wonder what you guys think about possibly retrofitting them (or something like them) to be T50rp ear cups??
 
http://www.amazon.com/Ironwood-Gourmet-Acacia-4-inch-2-5-inch/dp/B000EVIWS2/ref=sr_1_18?ie=UTF8&qid=1450456790&sr=8-18&keywords=salt+box
 
I know the lid would need to be trimmed and routed to fit the drivers flush. I would probably sand the bottom part to make it a bit more rounded as well. Seems like they may be large enough diameter to work but would be cutting it close. It seems like they could maybe be modded with just a few tools.
 
Dec 18, 2015 at 12:45 PM Post #2,002 of 2,870
  I've had my T50rp's for about two years now and love them to death. They are based on BMF mods with a few tweaks. I've always wanted to had bamboo or wooden earcups but the lack of tools (lathe, etc, etc) has prevent the dream. Recently I saw these and wonder what you guys think about possibly retrofitting them (or something like them) to be T50rp ear cups??
 
http://www.amazon.com/Ironwood-Gourmet-Acacia-4-inch-2-5-inch/dp/B000EVIWS2/ref=sr_1_18?ie=UTF8&qid=1450456790&sr=8-18&keywords=salt+box
 
I know the lid would need to be trimmed and routed to fit the drivers flush. I would probably sand the bottom part to make it a bit more rounded as well. Seems like they may be large enough diameter to work but would be cutting it close. It seems like they could maybe be modded with just a few tools.

Thats slick. But a little further down, these might be a better acoustic profile.
 
http://www.amazon.com/Naturally-Med-Olive-Sugar-Keeper/dp/B004IOS65K/ref=pd_sim_79_3?ie=UTF8&dpID=417MjVWLIPL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=04TKZQQ14KXX3ZD07Z1A
 
Dec 18, 2015 at 1:26 PM Post #2,004 of 2,870
  Yeah I saw those as well but was worried about the 3" diameter. I don't have the measurements of the drivers handy but I was worried that may be cutting it close.


I think they have a couple of different sizes of that one.
 
Dec 18, 2015 at 7:12 PM Post #2,006 of 2,870
I think BMF put them on page one if you need completely detailed measurements. Or I think I have them somewhere from days past

 
Here are the Thunderpants specs from Smeggy:
 
Quote Smeggy:
 
Ok, to follow up with some real, actual measurements...These are what I would call the ideal but it can vary in depth and complexity as many so called 1" boards are actually more like 7/8" so adjust to suit what you have available. 
 
The cups and baffles are 4" in diameter.

Cup inside diameter is  3 1/4"

Cup cutout depth is 3/4" deep. [...BMF: I think 3/4" is too shallow. There is not enough room for damping materials and for "breathing." I think 1.25 inch to 1.5 inch inside depth works better.]

Cup overall depth is 1" [...BMF: 1.5 inch to 1.75 inch]

Baffle depth is 1/2"

Inner recess is 3/8" with a 1/16" ridge, this forms the inner surface with a raised lip to seat the cups.

Outer lip is 1/2" deep (where the pads sit)

Dish is 5/16" deep for ear room.

Driver hole is 1 1/2" diameter

I normally trim the driver baffle pretty close to make is as small overall as I can as you can see in the pics to follow and an explanatory diagram. I'll post them shortly.
 
 
Just to go over the basics of a successful TP,
 
The cup needs to have a little space behind the driver. If you have to squeeze it closed, you don't have enough.
 
The driver needs to be sealed to the baffle.
 
The cable hole needs to be sealed to fill air gaps.
 
The pads need to seat well to the baffle face... flush screws and a flat 2mm 'craft foam**' type donut ring under the pads will help. The foam comes in sheets and you cut it with scissors.
http://www.craftsuppliesforless.com/kidscraftsupplies_foamsheets.html
 
The cup needs a small bass port of about 3/16 -1/8"
 
The baffle needs sealing to the cup to control the bass properly with the port. Again, a donut of craft foam will do nicely as a gasket.
 
Any damping on the rear of the driver should still allow easy airflow.
 
**You can replace craft foam with thin drought excluder or blutac from a home depot/lowes type place.
 
All of the above together will give you a nice dose of thunder! :)
 

 
 

 

 
 
 
(All photos by Smeggy)
 
End Quote Smeggy
 
 
 
 

 
Dec 20, 2015 at 1:36 PM Post #2,007 of 2,870
   
Be prepared for loose, boomy bass and midrange bloat.
 
I've come close (with a lot of modding trials) but I've never been able to approach seldom achieved the modded sound quality of drivers with the white material intact, after going "naked."  ...and it's irreversible.
 

 
RE: "Naked Driver" Mods
 
I almost forgot about this, but it was 3 years ago....Post 244 
It took me a lot of experimentation but I got pretty close to my best, after all. 
 
There are likely others who've done just as well and better.
 
Dec 20, 2015 at 1:55 PM Post #2,008 of 2,870
   
Be prepared for loose, boomy bass and midrange bloat.
 
I've come close (with a lot of modding trials) but I've never been able to approach the modded sound quality of drivers with the white material intact after going "naked."  ...and it's irreversible.
 
I hope you succeed where I've failed.

 
Yeah, that's why I edited my post, probably not going to do it, heh. In my mind I imagine the white paper just being another dampening layer, so it makes me think that it could be easily duplicated. However it's really solidly on there, would be hard to get that seal without glue or tape. So yeah, probably not going to do it - maybe I'll purchase another one if they go on sale one of these days.
 
Dec 20, 2015 at 5:25 PM Post #2,010 of 2,870
Has anyone heard and started modifying T50RP mk3?



I've been helping some people on the mk3 thread with what I know from the mk2s.
Looks like they've adopted the hype thread for modding too

Seems like the mk3s are mostly mk2s with the rear of the driver dampened. Essentially putting felt on the mk2s. I might be ordering some mk3s if I can't get my drivers sorted. Might be a bad solder job on my part

http://www.head-fi.org/t/763009/fostex-new-rp-headphones-t50rpmk3-t40rpmk3-and-t20rpmk3/525#post_12177809
 

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