Just listened to some Fostex T50RPs today... WOW!

[mrspeakers]

 
See post 2573 on this page.  Look at part #10: Dust cover.  Some have found removing this dust cover from the front of the driver provides more treble.  I removed it and held it up to light.  It is very thin and loosely woven.  Some have removed it and noticed improved treble.  I did not hear a difference, but I a deaf above 12k Hz.  People with intact hearing in the higher registers may hear a difference where I did not.
 
I'm not sure what you are referring to as bass ports covered with foam.  Where is the foam?  
 
The bass tuning port is at the bottom of the cups and covered with a slightly denser fabric  (part # 17: damper) compared to the thin dust cover.  I removed it and placed electrical tape over all 4 slits.  I slowly pulled the tape away exposing first only 1 slit, then 2, etc. until all 4 were open.  Some have found significant increase in bass as more slits are opened.  I did not notice a significant increase in bass when fully open; only a minimal change to my ears and I can hear down to 20 Hz.
 
FWIW:  There is a very small hole on the front/ear side of the baffle.  You can stick a paperclip through it and see where it comes out of the driver on the back side.  This, I assume, allows pressure equalization on either side of the baffle; in other words, the pressure is the same inside the cup chamber as outside.  You can experiment with fully open vs partially covered with tape vs fully covered with tape to see what effect, if any, is produced.
 
Let us know what you find as you continue your mods.
 
 

Vent tuning has the greatest effect when the white felt is removed. If that mod has not been made the ft dominates the damping of the bass. If the felt is off the port is the main damping mechanism.

 

[bluemonkeyflyer]

Quote:

Vent tuning has the greatest effect when the white felt is removed. If that mod has not been made the ft dominates the damping of the bass. If the felt is off the port is the main damping mechanism.

mrspeakers,
 
What is "ft"?  
 
You have convinced me to take off the white felt from the backs of the drivers.  After doing so, am I correct that you completely sealed ~ 3.75 of the 4 vent slots in the cups with electrical tape and covered the tape with Paxmate?  
 
For the backs of the drivers, what/how is "stiff felt" different from craft felt and wool felt; and where do you find it?
 
I already have the dust cover off the ear side of the drivers, plasticine in the baffles, Paxmate Plus on the bottoms (not the sides) of the cups, and a felt reflex dot on the center compartment/housing plate for the hanger assembly screw; I am assuming, by dead-reckoning, that the center of the driver will make contact when baffles and cups are re-attached.  
 
Maybe I should put tape or a rubber reflex dot directly on the center driver square and remove the felt reflex dot from the hanger screw compartment plate?
 

 

[geetarman49]

My offer on post #2502 still stands. so far i've given away 5 pieces, 1 piece left.  send me a pm if you're not in a terrible hurry ... typical delivery to conus is ~ 2 wks.
 
Quote:

... I don't have the acoustic foam yet (have to order it) but I do have the modeling clay and the felt so far...

 

 

[geetarman49]

answered in post #2503
 
Quote:

...
 
For the backs of the drivers, what/how is "stiff felt" different from craft felt and wool felt; and where do you find it?
 
...
 

 

 

[bluemonkeyflyer]

^ Thanks, geetarman49.  I keep up with this thread but obviously missed/forgot your answer in post 2503.  I will check for stiffened felt at Michaels tomorrow.
 
RE: Paxmate Plus, sounds like you and I have sent out a lot of free Paxmate to fellow modders over the past month or two.  

 

[geetarman49]

yeah... just happy to help fellow modders, but that postage keeps going up & up...

 

[mrspeakers]

Quote:

mrspeakers,
 
What is "ft"?  
 
You have convinced me to take off the white felt from the backs of the drivers.  After doing so, am I correct that you completely sealed ~ 3.75 of the 4 vent slots in the cups with electrical tape and covered the tape with Paxmate?  
 
For the backs of the drivers, what/how is "stiff felt" different from craft felt and wool felt; and where do you find it?
 
I already have the dust cover off the ear side of the drivers, plasticine in the baffles, Paxmate Plus on the bottoms (not the sides) of the cups, and a felt reflex dot on the center compartment/housing plate for the hanger assembly screw; I am assuming, by dead-reckoning, that the center of the driver will make contact when baffles and cups are re-attached.  
 
Maybe I should put tape or a rubber reflex dot directly on the center driver square and remove the felt reflex dot from the hanger screw compartment plate?
 

 
"ft" was felt before auto-correct on my iPhone.  
 
Stiff felt was craft felt from a craft store.  Some people swear by fancy Italian wool felt but I tried a few and didn't notice anything.  
 
I plan to experiment with some reflex dots.  Let me know if you try some various approaches and how they work.  If you put one on the driver the existing one will be out of the reflection path so it won't have an effect.  

 

[rawrster]

I've done mostly minor mods since I don't have the acoustic foam (yet..) but I shall wait until I have done all the mods to my liking. I've removed the thin black felt by the bass ports and the white felt on the driver. I've also added some modeling clay in the baffle. I bought some felt at Michael's and replaced the white felt with the one I bought at Michael's so unless I'm mistaken all I have left is the acoustic foam and then adjusting the bass with electrical tape which I have somewhere.. I may also get some better pads so I'll start with the SRH840. I just did a search and it looks like B&H sell these. I wish I knew that earlier since I was close by today and yesterday but I'll stop by sometime next week and pick up a pair of the pads and go from there.
 
I kinda like how you can tune this headphone to suit your tastes with the mods. It gives it your own personal touch on it compared to most headphones where modding usually just means upgraded pads or cables.

 

[Questhate]

So today I finally got a chance to open these bad boys up. I pretty much followed the Rastapants template exactly because it seems to address the resonance issues in the chassis (mass loading baffles, and acoustic foam) and then leaves room to adjust for preference (bass port tuning, dampening material choice). What I thought would be a quick 20 - 30 minute process ended up taking closer to 2 hours. I took pictures along the way, so I thought I'd share: 
 
Virgin drivers:

 
The only non-drying modeling clay at my local crafts store, Michael's, was this Crayola one. I was very soft, which made it a bit messy to work with, but it did the job. I want to find something in between the density of this and dynamat eventually.

 
Baffle is mass loaded. I followed the Rastapants color scheme to pay homage to mrspeakers. I used a screwdriver to poke holes to break the smooth surface. 

 
Added a couple of strips of dynamat to the inside of the cup to mass load them. I don't think this is part of the official Rastapants configuration, but I have tons of Dynamat sitting around so I figured it couldn't hurt. I think MacedonianHero mass loads the inside of his cups with Dynamat. If anyone needs Dynamat, shoot me a PM. 

 
I lined the acoustic foam (Silverstone brand bought off Amazon) on the inside surface of the cup on top of the Dynamat. 

 
Only used 1/10th of one sheet of acoustic foam, out of the two sheets that came in the package. So, I probably have enough leftover to do 19 more headphones. If anyone needs acoustic foam, shoot me a PM and I'll gladly send you some. 

 
Peeling off the white felt on the driver. While technically this is an irreversible mod, that doesn't make it unchangeable. So, if I don't like the sound, I can always find similar material to put back on to bring it close to stock. But with it off, I could choose any material under the sun so taking it off was a no-brainer to me. 

 
Back of the driver in the nude. There is no dust cover on the back of the driver, so if you peel off the white felt, I'd recommend putting on another material for a bit of protection. 

 
Stiff felt from Michael's that I'm using for the back of the driver. 

 
I used rubber cement to apply the stiff felt Here is a picture of the finished driver with the white vent cloth removed. 

 
I'm using electrical tape on the outside of the cup for now, so that I can easily try different amounts to see which one I'll settle on. With the entire vent open. Right now I'm settling on blocking all except one vent. 

 
My SRH840 pads don't arrive until next Wednesday, so I'll likely wait until then to take the front driver cloth off. I did take a couple of strips of double-stacked acoustic foam and stuffed them underneath the earpad. Here's a picture of one inside the earcup, next to the other strip. 

 
So, how does it sound? In one word... wow. 
 
I only listened to this in stock form for about half an hour, but these are a clear improvement in every aspect, imo. Both ends are much more extended. Previously the bass did not extend very deep, and didn't have much impact. Listening to hip-hop songs, it was missing the lower registers which made music annoyingly thin. Well now the sound is much fuller, as the lower frequencies fill up much more space -- similar to switching over from laptop speakers to desktop speakers.
 
The treble has brightened up for the better. While the treble was rolled off and stuffed behind the midrange before, the details now pop out at you to give your brain a steady stream of stimulus. It's still not a bright headphone by any means, but it's detailed and exciting (with the right recordings) without being harsh.
 
The clarity in the midrange has gone up two or three notches. All of the elements in the music is much more defined and give a greater sense of transparency. In stock form, things were much too syrupy with all the cup resonances bouncing around. It made it almost seem like you're listening underwater.
 
Soundstage is very 3D and seems to have widened -- although it may just be perceived that way because the treble has brightened up. 
 
These have that very distinctive orthos flavor, that you either love or hate. They give a great sense of weight to vocals and instruments that are much more realistic than traditional dynamic drivers after you wrap your head around the orthos sound. 
 
Right now, I'm very pleased with how far $74 can get me. There are still a few things I want to play around with -- specifically bringing the upper mids a bit out more. The tonality of alto sax is a tad off on mine, and it's not quite airy enough for acoustic guitar pieces just yet. I'm hoping removing the earside driver felt will air things out. But as of right now, after running these through my test tracks for the past three hours, I can say that I'd be perfectly happy with these being my only set of headphones. They're not better than the LCDs (I'd have to wait until mine get back so I can really A/B them to get more indepth), but they do so many things right and don't have any gaping flaws. 
 
Big thanks to mrspeakers, joelpearce, leeperry, MacedonianHero, Kneeljung, bluemonkeyflyer and all the contributors in this thread

 

[LFF]

Quote:

So, how does it sound? In one word... wow.   
I only listened to this in stock form for about half an hour, but these are a clear improvement in every aspect, imo. Both ends are much more extended. Previously the bass did not extend very deep, and didn't have much impact. Listening to hip-hop songs, it was missing the lower registers which made music annoyingly thin. Well now the sound is much fuller, as the lower frequencies fill up much more space -- similar to switching over from laptop speakers to desktop speakers.
 
Soundstage is very 3D and seems to have widened -- although it may just be perceived that way because the treble has brightened up. 

Those were the biggest differences for me. The bass slam I got after the mod was truly night and day. The soundstage also went from being barely present to being very three dimensional with absolute accuracy.
 
Do report back when you get your new pads.

 

[Hennyo]

Ha! Great work Qh! I just modded mine today! Same materials. ; ) However, I'm a bit short on Paxmate / accoustic foam atm... That'll have to wait till Monday. I think before I peel the white cloth off I'm going to demo > White cloth > White cloth + the still felt on top. ( which is B0wl1ng's mod). Then I'll Make the choice from there. ;D Hmm, ygpm.

 

[bluemonkeyflyer]

Great job, Questhate. The pix really help.

I'm going to go full Rastapants tomorrow and also tweak my fake AT-ESW9 foster phones with 32 Ohm SFI transplanted tweeters. I'll post pix here and in the Orthodynamic Roundup thread.

 

[mrspeakers]

Quote:

 
 

 
 
I only listened to this in stock form for about half an hour, but these are a clear improvement in every aspect, imo. Both ends are much more extended. 
 
The treble has brightened up for the better. While the treble was rolled off and stuffed behind the midrange before, the details now pop out at you to give your brain a steady stream of stimulus. It's still not a bright headphone by any means, but it's detailed and exciting (with the right recordings) without being harsh.
 
The clarity in the midrange has gone up two or three notches. All of the elements in the music is much more defined and give a greater sense of transparency. In stock form, things were much too syrupy with all the cup resonances bouncing around. It made it almost seem like you're listening underwater.
 
Soundstage is very 3D and seems to have widened -- although it may just be perceived that way because the treble has brightened up. 
 

Nice job removing the felt!  I never got one of in one piece.  This man knows how to use an exact-o knife!
 
You summed up the major changes very well, but there's one more that to me is crucially important; I can hear way deeper into the midrange.  It's particularly emphasized when you listening to really complex multi-tracked vocals or choral works.  While the mids are brought to a more neutral stance than stock, they are also simultaneously way, way, way more revealing.
 
With the T50 mod I hear really deep into the music.  I can hear discrete voices that once were blended into a more diffuse and blended vocal "sound." For example listening to Born on Punches or Houses in Motion on the fabulous 24/96 remaster of Remain in Light from HDTracks.  Every detail of Brian Eno's and David Byrne's stunning backing vocals stands out in bass-relief.  Localization is precise, and the interplay of the harmonies, which often sound like just 1-2 voices, creates a richly textured interplay that creates a radically different experience to the music.  
 
I'm a huge Eno fan, and am finding even more to enjoy in this artist because I hear to darn deep into the music with these cans.  
 
 
 
 
 
 

 

[LFF]

 
Quote:

With the T50 mod I hear really deep into the music.  I can hear discrete voices that once were blended into a more diffuse and blended vocal "sound."
 

X2! I can hear such minor nuances now that I have never heard in my music collection before. On one recording, I could hear people walking around...never heard that before but thanks to the bass extension and detail, I do now. In a lot of classical works, I can now distinguish individual instruments from the overall blend of the sound. In many a vocal recording, I can hear their lips open just before they begin to sing. These headphones, once modded, go extremely deep into the music...so detailed and clear that it's not even looking through glass...it's being there. This is like having a headphone that is of Olympic status while most other headphones are still stuck in a todler/kids pool.
 

 

[Hennyo]

I have GOT to recable these... I think they'll improve to very close to LCD levels - recabled or not.. How about Silver dragon v3?? $365 recable!!
 
! I think I'm goona do it. Or blue dragon v3. Trololol!
 
Stock lcd-2 cable is like quad braid 28 or 26 awg copper. And braided... with dielectrics and such... and shielding.. Whereas this cable is lacking imo. I think we could crank a lot more cleanliness and overall perception of wideness / crisp slam with a better copper cable and we could create something entirely new with a silver recable.. It would be way, way beyond stock... I think we can give the LCD-2 a real curbstomp for its price. While a great headphone, it's time we became disenchanted with it. (Hopefully I didn't come off as too harsh. =d Sorry