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Fostex T50RP Incremental Mods and Measurements - Page 57

post #841 of 1146

I changed my Alpha pad configuration a bit since the last time I posted on here. Ultimately, there are two big problems with the Alpha's when going straight from 840's using DBV#3: piercing highs, and hollow mids (from the mid-bass hump that BMF describes). My final mod (below) is comparable to the HE-500's with the jergpads: A dark, downward sloping, and intimate signature. The hollowness was fixed from the Paxmate on the earside (IIRC) as well as my somewhat odd usage of cotton balls inside. Microfiber cloth in front of the driver helps with piercing highs.

 

Inside:

-clay filled baffle and filled around edges for seal

-craft stiffened felt behind driver with 4 bass boost holes (2 mm x 4)

-acoustipack foam in cup floors with paxmate ladder rungs

-adhesive felt in center column

-2 teased apart cotton balls around the center where I have 1 unteased cotton ball directly behind the driver (help hold on stiffened felt and also to help the treble up)

 

Earside:

-remove felt in front of driver (not necessary, I was just messing around)

-paxmate to cover all areas with remaining felt on earside (square hole cut out for driver)

-microfiber cloth square cut out and placed in cavity made by paxmate

-soft felt square cut out and placed in cavity above microfiber

post #842 of 1146

BMF,

How did the russian driver mod affect the sound?  Worth it in your opinion for experienced modders to do?

 

 

Cheers,

~OFS

post #843 of 1146
Quote:
Originally Posted by onefatsurfer View Post
 

BMF,

How did the russian driver mod affect the sound?  Worth it in your opinion for experienced modders to do?

 

 

Cheers,

~OFS

 I have wondered this myself, still going to buy a t50 at some point for tinkering. And that russian mod always intrigued me. I never really was able to find any straight forward reviews on it either.

post #844 of 1146
Quote:
Originally Posted by Thujone View Post
 

I changed my Alpha pad configuration a bit since the last time I posted on here. Ultimately, there are two big problems with the Alpha's when going straight from 840's using DBV#3: piercing highs, and hollow mids (from the mid-bass hump that BMF describes). My final mod (below) is comparable to the HE-500's with the jergpads: A dark, downward sloping, and intimate signature. The hollowness was fixed from the Paxmate on the earside (IIRC) as well as my somewhat odd usage of cotton balls inside. Microfiber cloth in front of the driver helps with piercing highs.

 

Inside:

-clay filled baffle and filled around edges for seal

-craft stiffened felt behind driver with 4 bass boost holes (2 mm x 4)

-acoustipack foam in cup floors with paxmate ladder rungs

-adhesive felt in center column

-2 teased apart cotton balls around the center where I have 1 unteased cotton ball directly behind the driver (help hold on stiffened felt and also to help the treble up)

 

Earside:

-remove felt in front of driver (not necessary, I was just messing around)

-paxmate to cover all areas with remaining felt on earside (square hole cut out for driver)

-microfiber cloth square cut out and placed in cavity made by paxmate

-soft felt square cut out and placed in cavity above microfiber


Thank you Thujone and BMF once again. I appreciate your tolerance and help with DIY noobs like me :)

So far, I did everything you did. Except, there's more treble coming out of my right earcup than my left.. I'm going to see what the cause is. I can only assume it's the cotton because I had to apply a little pressure to squeeze the cup and cover together. ALTHOUGH, I do say I love the solid sub bass and punchy mid bass I'm getting. The bass doesn't bleed into the mids which is a huge plus! =D

post #845 of 1146
Quote:
Originally Posted by Nec3 View Post


Thank you Thujone and BMF once again. I appreciate your tolerance and help with DIY noobs like me smily_headphones1.gif


So far, I did everything you did. Except, there's more treble coming out of my right earcup than my left.. I'm going to see what the cause is. I can only assume it's the cotton because I had to apply a little pressure to squeeze the cup and cover together. ALTHOUGH, I do say I love the solid sub bass and punchy mid bass I'm getting. The bass doesn't bleed into the mids which is a huge plus! =D

I'm glad it's at least halfway working out! tongue.gif If the treble can't be fixed with stuffing, try adding more layers of felt or microfiber in front of the driver.
post #846 of 1146
Quote:
Originally Posted by Thujone View Post


I'm glad it's at least halfway working out! tongue.gif If the treble can't be fixed with stuffing, try adding more layers of felt or microfiber in front of the driver.


I'm a bit skeptical about adding microfiber in front of the driver, wouldn't this muffle the mids in the process?

post #847 of 1146
Quote:
Originally Posted by Nec3 View Post

skeptical
hesitant.
post #848 of 1146
Quote:
Originally Posted by c61746961 View Post


hesitant.


hahaha, fair enough, I guess it's all about experimentation. I'll give it a go then :)

post #849 of 1146
Quote:
Originally Posted by Nec3 View Post


I'm a bit skeptical about adding microfiber in front of the driver, wouldn't this muffle the mids in the process?

Not at all. I can't remember the exact post in the T50RP mega thread but I got the idea from a different user who had treble issues. He measured the headphones before and after and it was found that it reduces treble around 8kHz (sibilance) and everything else remains untouched, a life saver for me and my sensitive ears.
post #850 of 1146
Quote:
Originally Posted by Thujone View Post


Not at all. I can't remember the exact post in the T50RP mega thread but I got the idea from a different user who had treble issues. He measured the headphones before and after and it was found that it reduces treble around 8kHz (sibilance) and everything else remains untouched, a life saver for me and my sensitive ears.


Nice. I'll give that a try as well....not a big fan of sparkly treble either.

post #851 of 1146
Thread Starter 
Quote:
Originally Posted by Nec3 View Post


I'm a bit skeptical about adding microfiber in front of the driver, wouldn't this muffle the mids in the process?

Read "Tuning Rules of Thumb" near bottom of Post 1 in this thread.
post #852 of 1146
Thread Starter 
Quote:
Originally Posted by onefatsurfer View Post
 

BMF,

How did the russian driver mod affect the sound?  Worth it in your opinion for experienced modders to do?

 

 

Cheers,

~OFS

OFS,

 

Enlarging the magnet frames on the ear side, only, reduces sensitivity by about 15 to 20%. Enlarging both ear side and rear side magnet frames makes them too inefficient without appreciable sound quality improvement. 

 

Ear side, only, magnet frame modification results in different voicing and more bass. I am still trying different damping schemes so "the jury is still out" with regard to the question of, "Is it worth the effort?"

 

To my ears, I like the sound of both Russian Modified magnet frames and stock magnet frames. Sort of like different flavors. The Russian mod works really well for me by making them completely closed - sealing all 4 cup vent slots.

 

The Radical Russian Roulette mod may be just what is needed for those who want more bass and/or completely sealed cups. Note, an Amp is mandatory.

 

I think there is a lot of untapped audio goodness to this labor-intensive modification. It will take experimentation, patience, and time to find out what works best. I hope that some experienced modder will take it on and post results/recommendations for effective damping schemes. I will do the same but have half a dozen modification projects in the works so it may be a while.

post #853 of 1146

Alright, back to square one. Again BMF mods are frighteningly consistent; MY T50RP'S SOUND COMPLETELY FLAT with a slight recessed bass response. I don't have any measuring kits to prove it, but I'm going by ear with 20-20 frequency sweeps.

I used the dense foam that came with my computer's graphics card in the baffles, 2 stretched cotton balls that slightly compressed the driver, covered all four ports on the earcup with electrical tape, felt in front of the drivers (finally, the treble isn't piercing anymore), and underneath the felt, I covered the bass vent hole with electrical tape.

This is what I faced

Pros:
-Flat
-Sub bass, mid bass, decent treble
-Black background (It feels as if my ears are getting sucked into the headphones. It's a pressure-like feeling that is a similar sensation with noise-cancelling headphones)
-Smooth sound (due to felt in front of drivers)
Cons:
-There is nothing special. Everything is there with nothing popping out
-I didn't manage to get a basshead can
-Channel imbalance (I might need an amp more powerful than an E12...don't want to risk re-wiring for dual input)


Edited by Nec3 - 12/2/13 at 6:30pm
post #854 of 1146

What happens when you remove the cotton completely?

post #855 of 1146
Quote:
Originally Posted by Thujone View Post
 

What happens when you remove the cotton completely?



I'm an idiot. I removed the cotton and left the foam baffles. I had bass.
LOL, what was I even thinking. Thanks Thujone, I'm going to remove the cotton right now and see where it gets me. I'll just have to get carpet tape or something to make sure the foam baffle doesn't fall out. :)

edit: I HAVE BASS, THUJONE AND BLUEMONKEYFLYER YOU'RE BOTH THE BEST, WOOO! :basshead:


Edited by Nec3 - 12/2/13 at 7:47pm
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