Just listened to some Fostex T50RPs today... WOW!
Oct 31, 2011 at 11:44 PM Post #4,351 of 11,345


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Well I guess if your'e going to do that I might as well post the mods that are done to mine so its perfectly clear what I have right now.  I'm not sure if yours is 100% the same:
 
- SilverStone acoustic foam covering the inside of the cup, no foam on headband hanger stud
- No material on back of driver except for a square of electrical tape on the center square acting as a reflex dot
- Plasticine mass loading the interior side of the baffles and sealing the baffle (plasticine on the "rim")
- Two TRIPLE SIZED cotton balls, teased, inside the cups.  I used two because Mrspeakers and BMF found that something like 6 regular balls sounded best.  2 x 3 (triple) = 6
- Dynamat on ear side of baffle
- Shure 840 pads with cotton ball "bratwurst" underneath rear of the pad to angle the pads
 
- I also have a leather headband mod still because I find it super comfortable, but that doesn't affect sound so yeah.
 
 
Try it if you like, I don't take credit for most of it because its other peoples findings, but it sounds great.


That's exactly what I'm going to do. ; ) Right down to the pads. Does the dynamat make any difference? Did you isolate test that one?
 
 
Oct 31, 2011 at 11:45 PM Post #4,352 of 11,345


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This is also what I'll try before applying the improved Rastas on pages 270-80. My set arrives tomorrow. Rasta 2 vs ^ stated mod, vs Rasta 2i which measures better than LCD-2. If Luis obliges, I would love to own a pair of Paradox's as well. (As I believe they are the best T50 has to offer. Followed quite closely by the constantly evolving Rastas. Which measured phenomenal. Please observe, one of the most prolific Stax users opinions about the modded T50rp:
 



Henyo, what's Rasta 2i? I have never heard about it.
 
Oct 31, 2011 at 11:52 PM Post #4,354 of 11,345


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That's exactly what I'm going to do. ; ) Right down to the pads. Does the dynamat make any difference? Did you isolate test that one?
 



No idea.  I bought it and slapped it on eventually and figured it didn't hurt the sound so I didn't want to peel it off.  I didn't want to take off the acoustic foam from my cups because I ran out so I didn't put any in there, but I kind of think it does next to nothing because the amplitudes of the frequencies that the Dynamat is damping are so mall.  It would be more effective if the amplitude was higher (that sounds weird) by that I mean you would see more affect with higher amplitude.  Its hard to tell with the amplitudes we're dealing with.
 
Nov 1, 2011 at 12:38 AM Post #4,356 of 11,345


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Anyway, I do have the plasticine for the baffle filling, and I just found a huge bag of quilt filling...cotton-y stuff made from polyester.  Really thick and fluffy though, not sure how much good this would be for anything.


I had something very similar in my cups; recycled polyester, as I recall. I quite liked the sound. My one concern, though, was the crackling -- maybe static? -- I noticed when it was in place. I removed it and replaced it with 2 cotton balls/cup. Note that most pharmacies carry both cotton and rayon balls. I haven't tried the rayon, but was very satisfied with the cotton.   
 
 
Nov 1, 2011 at 1:09 AM Post #4,357 of 11,345
With further listening, I've found that no fabric on the back of the driver but the cups filled with cotton -- along with correct porting -- leads to better quality sub-bass with a deeper perceived extension.  I guess that's something to look forward to.  I'm just really surprised how well the cotton in the cups works.
 
Nov 1, 2011 at 1:17 AM Post #4,358 of 11,345


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wow cotton in cups makes a big difference... now my t50rp sounds like my sr325i, just smoother and with less bass. i think i like it actually.



I did some measurements on that (lost that data, so I can't plot it) but the stock cans had pretty poor frequency response, with bass rolling off around 100Hz, peaky mids, and very strong resonances.  Stuffing with cotton calmed the resonance down, but cotton + paxmate way more.  The frequency response with just cotton was also still pretty inferior to adding absorptive foam.  
 
I will do some comparative mods next, including with the stock felt for a new design, and also showing the effect of pads (note that pads change a given config, but no pad is "good" or "bad" in an absolute sense, they all need tuning...).  Some will work better with naked drivers, others with stock felt, others with other products, etc.
 
This will take a while, work is a priority right now...
 
Dan Clark Audio Make every day a fun day filled with music and friendship! Stay updated on Dan Clark Audio at their sponsor profile on Head-Fi.
 
@funCANS MrSpeakers https://danclarkaudio.com info@danclarkaudio.com
Nov 1, 2011 at 1:19 AM Post #4,359 of 11,345


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With further listening, I've found that no fabric on the back of the driver but the cups filled with cotton -- along with correct porting -- leads to better quality sub-bass with a deeper perceived extension.  I guess that's something to look forward to.  I'm just really surprised how well the cotton in the cups works.


LFF cooked up a great sounding system leaving the stock felt in place.  He got deeper and flatter bass than I have been able to with felts or a bare driver, though I'm now tuned to about -3db at 24Hz, his go lower still (btw, these are both exceptional numbers). 
 
I've only dabbled in stock felt with cotton to run a few "from stock" exercises to show specific affects of materials.  
 
Dan Clark Audio Make every day a fun day filled with music and friendship! Stay updated on Dan Clark Audio at their sponsor profile on Head-Fi.
 
@funCANS MrSpeakers https://danclarkaudio.com info@danclarkaudio.com
Nov 1, 2011 at 1:49 AM Post #4,360 of 11,345
^My next goal with the Silver Pawstex
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Nov 1, 2011 at 1:59 AM Post #4,361 of 11,345
i hear a noise now when no music is playing. i noticed it before when i listened to music but i thought its noise from the recording. i'm sure it's because of the cotton since it never happened before. you guys notice it too?
 
Nov 1, 2011 at 2:07 AM Post #4,362 of 11,345
The right side cup of my T50RPs makes a buzzing sound when I'm talking to somebody over skype, or during lyrics with hard consonant sounds.  I've taken it apart many times and fiddled with various things but can't find the source of the sound.  Any ideas?  Has anybody else had this problem?
 
Nov 1, 2011 at 2:32 AM Post #4,363 of 11,345
i think you should use Deoxit on the cable plug and on the cable socket.
 
Quote:
The right side cup of my T50RPs makes a buzzing sound when I'm talking to somebody over skype, or during lyrics with hard consonant sounds.  I've taken it apart many times and fiddled with various things but can't find the source of the sound.  Any ideas?  Has anybody else had this problem?



 
 
Nov 1, 2011 at 2:53 AM Post #4,364 of 11,345
Duct tape works instead of electrical tape if you're using that as a reflex dot. Just in case anyone had duct tape and not electrical tape like myself...
 
Still just wish I could get more sub-bass out of these...
 
Nov 1, 2011 at 3:08 AM Post #4,365 of 11,345
Anyone tried very fine wood wool or steel wool in place of the cotton balls? 
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Not really sure what it would do but I want to try these just for the sake of modding once I get my T50RPs, maybe not the steel wools since it is magnetic.
 

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