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

Oct 25, 2011 at 2:29 AM Post #4,201 of 11,346
I've been playing with waterfalls tonight, and am pretty comfortable with the way the tests and software are working.  
 
The following is a waterfall of a good measurement of my LCD2:
 

 
This is the Rastapants 2 PLUS 6-7 regular cotton balls, 3.5 vent slots closed, and the center inside driver square with a reflex dot (just added, it took a bite out of but didn't totally eliminate the 3-5KHz dip):
 

 
From these charts, which reproduce consistently with variations expected based on exact microphone position, you can see the T50 Rastapants 2 has a cleaner and faster decay and except for the 3-5K region has more mid and treble output with a smoother response.  
 
Before anyone makes too much of the comparative charts, it is extremely probable that some of the spectrum from 500-1000Hz on the LCD and at a lower level on the RP2 is ambient noise from disk drives and other junk in the house, so focus more on the highs. I am pretty certain that the LCD2 performs better than the waterfall indicates, given that it's a fully open design high frequency ambient noise is almost certainly polluting the response (not so the resonance at 9K, that was in Purrin's tests, too, and the resonance is clearly part of the system, not my lab noise).  Until I build an anechoic test box a la Tyll, open air cans will likely test at a disadvantage.  
 
Here is the frequency response (the sound is freaking ROCKING tonight):
 

 
I'm also very pleased by the THD:
 

 
It's pretty much less than 1% below 100Hz, and between .05 and .15% through the rest of the range.  I suspect the spike at 600Hz correlates to the notch in the frequency response, where there is a bit of ringing.  Same thing at about 42Hz. A good rule of thumb is a notch in the response will indicate some kind of resonance/standing wave, at 42Hz though, I am wondering if this is a panel resonance.
 
Since I see Tyll is watching the thread, I think I can pretty safely say these are pretty good results.  Running results without moving the head has generated plats that have been within a 1-2 DB variance, and if I put the phones back in the same spot are highly repeatable....  Tyll, any comments on the performance you see here?  I haven't calibrated the round trip DAC->ADC to calibrate the electronics, so they may be contributing a bit of distortion here that's not accounted for...
 
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Oct 25, 2011 at 2:32 AM Post #4,202 of 11,346


Quote:
tyll hertsens said:
Nicely done, mate. Those measurements look pretty good.  
 
:thumbsup
 
Click to expand...


Thanks! Now I just need a big box to sit in while I run the tests...  
L3000.gif

 
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
Oct 25, 2011 at 2:47 AM Post #4,203 of 11,346
hmmmm.  I'm inspired to pull my modded T50s out for a play around, I am gonna go with the flow and will christen my T50RPs errr....Supermodelpanties. 
biggrin.gif

 
Oct 25, 2011 at 3:10 AM Post #4,204 of 11,346
Quote:
mrspeakers said:
 
This is the Rastapants 2 PLUS 6-7 regular cotton balls, 3.5 vent slots closed, and the center inside driver square with a reflex dot (just added, it took a bite out of but didn't totally eliminate the 3-5KHz dip):
Click to expand...


Great job, that's extremely impressive looking!
 
I've been playing around with reflex dots too, of various sizes and materials, and they seem to mostly boost >6k, that midrange dip is hard to get rid of.
 
My T20v2 which uses a completely different driver in the same enclosure has it too, so I'm not sure if that's just how Fostex tunes their drivers or if it's the enclosure that's doing it somehow.
 
 
Oct 25, 2011 at 11:51 AM Post #4,206 of 11,346
I had to post this...  I just literally ripped my t50's off my head when this song started playing in my random playlist today. I wont say why just play it and make sure the volume isnt too high, but turn it up as the first few seconds roll on. I've never had a headphone respond to this song the way the t50 does!!!
eek.gif

 
http://www.youtube.com/watch?v=nublH0a7yrw&hd=1
 
M
 
Oct 25, 2011 at 12:15 PM Post #4,207 of 11,346


Quote:
mrspeakers said:
I've been building a test capability so I can quantify my designs.  
 
Here is the frequency response of the Rastapants with the O2 pads (IMPORTANT NOTE:  The RP2 tested here has two mods from what I published: about 6-7 cotton balls/wool in each cup and the vent 50% closed.  These mods make a nice and easy upgrade, and work for the 840 pads, as well.  The 840 testing with the same RP2 setup indicates that 75-85% closed works pretty well, though I'm not done).   I validated the above results through multiple tests, which were actually quite consistent, and averaged 10 plots to generate these charts.
 

 
Here is the frequency response of the LCD 2:
 

 
A few notes:
 
1) These tests are on a flat baffle, which is not going to give the same curves as a "ear" or "head" measurement system.  In other words, they will look different from the test Tyll publishes, and they'll also be different what Purrin measures because his rig is somewhat different, as is his software.  The key thing to understand with headphone testing is that one testers charts can really only meaningfully be compared to more charts BY THAT TESTER.  And they should be seen as RELATIVE but not ABSOLUTE, as there are so many variables that affect results.  Tyll has written a ton of great stuff on why that is (and knows more than I do on this) so I won't repeat it...
 
2) The bass measurement is more accurate than mids/highs due to wavelengths so take high frequency results as a general indicator of response curve SHAPE, but not exactly what you'll hear (again, see Tylls blogs).  For example, my suspicion is that the deep notch at 4.5K on the LCD2 is probably a standing wave rather than a real hole in their frequency response, so don't go dissin' those cans because of it.
 
Results:  
 
The LCD2 has deeper extension below 30Hz.  The bump of the RP2 gives it a bit more bass slam and weight, sort of like the JH16 sound, which actually really is fun to listen to, and does not sound "boomy," but not as "absolutely accurate" as I'd like. I'd like to flatten the bass out a bit more and get a few more Hz out at the bottom.  It's not "too much of a good thing."  The sound, as you'd probably expect from the spectral tilt, is a bit warmer than the LCD2, though and the highs feel brighter.  I'd characterize the RP2 as sounding "bigger" than the LCD2, with a better defined top-end, but a bit less extension and linearity at the bottom.  
 
The RP2 has a notch from 3-5KHz that pulls the upper mids back a bit.  It's not objectionably obvious like a big spike in frequency response, but it will liven up the sound even further to address this, so I'll be giving it my best shot.  
 
I did do some waterfall plots but won't publish until I'm more confident in my testing skills.  I will say they validated one area that made me prefer the Rastapants 2; it has SUPER fast decay above 1.5K and less ringing than the LCD2 I tested.  And the LCD2 decay is excellent. 
 
Again, I wouldn't say this is absolute, I'm still learning my test rig setup, but it did validate one of the things I really like about the RP2.  It's possible the difference is how I tested vs. what I tested, if you follow, so for this reason, I don't want to publish the waterfalls until I am more confident I'm testing accurately. 
 
Thanks to Tyll and Purrin for some inspiration, ideas and direct input on testing.  My next post on mods will either be doing a fully reversible design or further optimizations on the Rastapants 2 to smooth those to areas of interest out.
Click to expand...

 
Awesome! Great work.
 
 
Oct 25, 2011 at 12:42 PM Post #4,209 of 11,346
OT, but just fyi and to take a slight respite from all this modding.
according to fostex jpn rep at rmaf & my own impressions:
1. th900 u.s. price will be $2k
2. th900 earcushions are incredible, better than lcd-2 on my ears
3. th900 earcups look & feel like colored plastic ... although very nice colored plastic
4. if it follows current trend of pricing for t50, look at street price of ~$800 for th900
5. soundwise for me, he500 > lcd-2 > th900
6. a higher end planar is still under consideration at fostex hq
7. supplies of t50rp's should reach retailers soon ... it's an ebb and flow response
 
Quote:
hdman said:
at 100,000 Yen ($1300 USD), I think I will be sticking to the T50RP's.
 
and
 
THERE NOT EVEN ORTHO'S
eek.gif

 
October 2011
Fostex will be launching the new TH900 Dynamic Headphones at CanJam @ RMAF which is to be held at the Denver Marriott Tech Center on October 14, 15, and 16, 2011.
TH900 Dynamic HeadphonesModel TH900 is a pair of flagship dynamic headphones from Fostex featuring newly developed drivers with 1.5 tesla magnetic flux density and housings beautifully finished by Japanese lacquer.
  1. Newly developed 50mm dia dynamic type driver units with 1.5 tesla magnetic flux density
  2. Beautiful housing finished by “Urushi”, Japanese lacquer, made by traditional craftsmanship
  3. Headphone cable made of high purity OFC of 7N grade (99.9999%)
 
 
The D7000 T1 hybrid monster has arrived!!! Muhuhahahaa
Click to expand...



 
 
Oct 25, 2011 at 1:03 PM Post #4,210 of 11,346
840 pads fit. It's tight. Make sure you have cleaned up and covered the Dynamat goo with felt or tape. You don't want your pads sticking to the Dynamat and possibly tearing when you later remove them.
 
Someone here suggested this approach. It's easy:  Roll the part of the pad that secures it to the cup back over the ear pad; sort of inside out. Place the pad in postion on the baffle and roll back the other way onto the cup.
 
Quote:
proid said:
@BMF: Did you try BMF #6 with shure 840 pad or it only work with stock pad?
Click to expand...



 
 
Oct 25, 2011 at 1:08 PM Post #4,211 of 11,346

Originally Posted by geetarman49 /img/forum/go_quote.gif
 
a higher end planar is still under consideration at fostex hq
Click to expand...

 
You spoke to the CEO of Fostex or sumthing?
tongue.gif


If that ever happens, we can thank smeggy because he's the one who started the T50RP frenziness that makes every new batch out of stock everywhere. Hopefully, that'll make Fostex realize that there very much is a market for a higher end ortho and I rest my case that they've been in the ortho business for decades and they have done their R&D homework...they're not just another stellar markup startup company that didn't exist 2 years ago trying to cash in big time on orthos while they still can.
 
 
Oct 25, 2011 at 2:16 PM Post #4,212 of 11,346
Apparently they are out of stock everywhere less because of demand and more because a lot of Fostex's facilities were damaged in the Tsunami.  I was told they not only lost equipment and infrastructure but also employees.  :-(
 
Oct 25, 2011 at 2:46 PM Post #4,213 of 11,346

fostex had a nice display at rmaf with amps, dacs and phones for trial.  i spoke on two separate days with the lead representative of fostex (jpn) at the show.  he seemed to be mildly surprised that there was a current lack of stock of the t50 & checked with another fostex rep on the u.s. stock situation before replying back to me that the local stock(s) will be replenished soon, if not already (put your orders in now, folks).
 
the current interest in hi-end planars was not lost on them ... neither was the modding trend on the t50 ... which was why the carefully worded response back to me that such a phone is still under consideration ... i tried to gauge not only his strict verbal reply but his expression as well ... i took that to mean that it is more of a marketing issue rather than anything technical (it would not surprise me if they already have such a working mule in their lab).  ofc, you are right - fostex is no newcomer & they react very carefully to market situations.  the fact that the 900 is already on the books for early 2012 release along with the 32-bit dac/hpa deems it unlikely that they would entertain such a prospect (hi-end planar) in the early new year ... but after??  
Quote:
leeperry said:
 
You spoke to the CEO of Fostex or sumthing?
tongue.gif


If that ever happens, we can thank smeggy because he's the one who started the T50RP frenziness that makes every new batch out of stock everywhere. Hopefully, that'll make Fostex realize that there very much is a market for a higher end ortho and I rest my case that they've been in the ortho business for decades and they have done their R&D homework...they're not just another stellar markup startup company that didn't exist 2 years ago trying to cash in big time on orthos while they still can.
 
Click to expand...



 
 
Oct 25, 2011 at 3:37 PM Post #4,215 of 11,346

rhythmdevils said:
Apparently they are out of stock everywhere less because of demand and more because a lot of Fostex's facilities were damaged in the Tsunami.
Click to expand...


It was already the case way before the Tsunami disaster, the T50RP supply has never reached the demand steadily ever since I've had interest in orthos.

geetarman49 said:
fostex is no newcomer & they react very carefully to market situations.  the fact that the 900 is already on the books for early 2012 release along with the 32-bit dac/hpa deems it unlikely that they would entertain such a prospect (hi-end planar) in the early new year ... but after??  
Click to expand...


Well, they're our only hope anyway for an affordable world class ortho, and it's not like I would really mind waiting another year or two either ^^
 
 
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