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post #4186 of 10570



     Quote:

Originally Posted by mrspeakers View Post

Alas, even if I knew what he did, I wouldn't share without LFF's permission...  Sorry.  He has only said a) he uses the Fisher 003 pads, and b) all mods were reversible, and he shared his super comfy headband design, which is definitely worth trying.  It takes the pressure point off the top of the head, and it's very easy to make.  


Any chanceon a link to that famous LLF headband?
 

 

post #4187 of 10570
Quote:
Originally Posted by Twinster View Post

     Quote:

Any chanceon a link to that famous LLF headband? 

 


LFF has since updated it, but here's the gist:

http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/2895#post_7782196

post #4188 of 10570

Has any actually had a successful attempt at an open-mod of these yet?  Or has anyone just listened to them with the back ear up off?  I'd be really pumped to do a mesh grill open-back mod and make these super flat.

post #4189 of 10570

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.

 

RP2 O2 50% Freq.png

 

Here is the frequency response of the LCD 2:

 

AVG 10 LCD2.png

 

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.

 

 

 


Edited by mrspeakers - 10/24/11 at 6:06pm
post #4190 of 10570
Quote:
Originally Posted by wdahm519 View Post

Has any actually had a successful attempt at an open-mod of these yet?  Or has anyone just listened to them with the back ear up off?  I'd be really pumped to do a mesh grill open-back mod and make these super flat.


It was tried and reported to have pretty bad results, but that doesn't mean someone else shouldn't try.  I will say that as the performance varies hugely based on the venting on the cups, it's probably a foregone conclusion having the driver totally open on one sound will sound pretty bad.  The driver was designed to have a semi-closed/closed enclosure, probably to balance out the air-mass on both sides of the driver to maximize linearity.

post #4191 of 10570
Quote:
Originally Posted by CYoung234 View Post

Here is a link to a pdf that shows the specs for Original Dynamat. Yes, I mass loaded the baffles using actual Plasticine. No, I do not have the original white driver felt. So far, I am getting good results with the 3M Transpore. I think I just need to ad a couple more pieces, or maybe dynamat the ear side to tweak the high frequencies just a bit.

 

http://www.dynamat.com/technical_specs_dynamat_original.html 

 

Just an update. Switching to Shure 840 pads with the last mods I did really helped the high end to get where I needed it. I think I am done for now (except for making one more pair for my twin brother to try out! I will likely not use as much Dynamat in this pair, but may try a layer of it on the ear side.
 

 

post #4192 of 10570
Quote:
Originally Posted by mrspeakers View Post

It was tried and reported to have pretty bad results, but that doesn't mean someone else shouldn't try.  I will say that as the performance varies hugely based on the venting on the cups, it's probably a foregone conclusion having the driver totally open on one sound will sound pretty bad.  The driver was designed to have a semi-closed/closed enclosure, probably to balance out the air-mass on both sides of the driver to maximize linearity.



You're correct, I do remember now that I think back on it.  I'll have to try your cottonball idea.  Did you have nothing except for cotton balls and venting for those measurements?

post #4193 of 10570

@ mrspeakers - how do you fit 6-7 cotton balls in each cup?  If I had nothing in my cup to start with I could maybe squeeze 4 in there... how big are you balls? tongue_smile.gif

 

 

I agree with your "fun" sound analogy with the RP2. I am running a-lot of clay near the driver tapered out to just filling the baffle tray at the rim. paxmate in the back of the cup and up the short sides but not on the curved areas. Lastly 2 jumbo cotton balls in the cup covering the factory reflex dot/screw port area and leaving a hole open in the cotton for the bass vents which are 50% covered. This setup is the most articulate and detailed with treb extension, while still remaining fun in the bottom end with loads of tight hard hitting fast bass "that I have tried". I will enjoy this fun sound for a while as a rest stop along the journey to find the neutie can i'm searching, I hope I can find it!  ps: i'm using the o2 pads, they are sort of a round peg square hole deal though being that the t50 is oval and the o2 is round... hard to get a good seal imo.

 

Have fun with your new test setup and we're with you here through your triumphs and failures smile.gif

 

M

post #4194 of 10570
Quote:
Originally Posted by mmayer167 View Post

@ mrspeakers - how do you fit 6-7 cotton balls in each cup?  If I had nothing in my cup to start with I could maybe squeeze 4 in there... how big are you balls? tongue_smile.gif

 

 

I agree with your "fun" sound analogy with the RP2. I am running a-lot of clay near the driver tapered out to just filling the baffle tray at the rim. paxmate in the back of the cup and up the short sides but not on the curved areas. Lastly 2 jumbo cotton balls in the cup covering the factory reflex dot/screw port area and leaving a hole open in the cotton for the bass vents which are 50% covered. This setup is the most articulate and detailed with treb extension, while still remaining fun in the bottom end with loads of tight hard hitting fast bass "that I have tried". I will enjoy this fun sound for a while as a rest stop along the journey to find the neutie can i'm searching, I hope I can find it!  ps: i'm using the o2 pads, they are sort of a round peg square hole deal though being that the t50 is oval and the o2 is round... hard to get a good seal imo.

 

Have fun with your new test setup and we're with you here through your triumphs and failures smile.gif

 

M


I used "regular" balls.  My balls clearly aren't as big as yours.

 

beerchug.gif

post #4195 of 10570
Quote:
Originally Posted by wdahm519 View Post

You're correct, I do remember now that I think back on it.  I'll have to try your cottonball idea.  Did you have nothing except for cotton balls and venting for those measurements?


The configuration was a full Rastapants 2 with O2 pads, and the two mods I mentioned.  

post #4196 of 10570

I guess so, I think regular balls might be easier to play with...  

 

 

 

Too far, my bad.

 

 

back to the grind.

 

M

 


edit: i hope my girlfriend never finds this post! 


Edited by mmayer167 - 10/24/11 at 7:48pm
post #4197 of 10570

Wow, really great looking plots. Acutally looks kind of like hd 650. (The fr that is, only it's Mach (2) faster and again, 'SUPER' shiny fast above that 1.5kish).

 

Any chance Purrin's going to post the fr's to the paradox and rp2? Dying to see them. ; ) Thanks for the hard work, and we're enjoying observing your experience with these cans. Bmf and all others, you too.

 

post #4198 of 10570

Quote:

Originally Posted by mrspeakers View Post

It was tried and reported to have pretty bad results, but that doesn't mean someone else shouldn't try.  I will say that as the performance varies hugely based on the venting on the cups, it's probably a foregone conclusion having the driver totally open on one sound will sound pretty bad.  The driver was designed to have a semi-closed/closed enclosure, probably to balance out the air-mass on both sides of the driver to maximize linearity.


When I modded my D2000s into open-backed headphones, I found that I had to raise the earpads off the frame of the headphone to get them to sound good. For those of you that aren't familiar with the D2000/5000/7000, the earpads have 4 plastic pegs on the bottom of them that are used to lock the earpads onto the frame of the headphone. Instead of locking them in, I instead rest those plastic pegs on the frame itself. In that aspect, they offset the earpads from the frame and provide airflow underneath the pads. If you didn't do that, they sounded pretty awful as open headphones.

 

Now, that said, I am NOT saying this will necessarily work for the T50RPs...but it might be something worth playing around with?

post #4199 of 10570
Quote:
Originally Posted by Hennyo View Post

Wow, really great looking plots. Acutally looks kind of like hd 650. (The fr that is, only it's Mach (2) faster and again, 'SUPER' shiny fast above that 1.5kish).

 

Any chance Purrin's going to post the fr's to the paradox and rp2? Dying to see them. ; ) Thanks for the hard work, and we're enjoying observing your experience with these cans. Bmf and all others, you too.

 


Purrin had a plot of a version I thought might be 2.1 but his tests showed me a couple of pretty poor areas, so I decided I needed to get equipped...  His plot wouldn't look anything like the RP2 or this version...

post #4200 of 10570
Quote:
Originally Posted by mrspeakers View Post

Thanks to Tyll and Purrin for some inspiration, ideas and direct input on testing. 

 


Nicely done, mate. Those measurements look pretty good.  

 

:thumbsup

 

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