Fostex T50RP Incremental Mods and Measurements

[GREQ]

It's been a long time since I've even touched a Fostex headphone or seen this thread.

Here is my T40RP mkII mod.

My goal was to make a fun, yet tasteful 'bass monster' headphone. I've got enough reference headphones already.
The biggest obstacle with modding these headphones is the crazy bass around 100hz that SO many mods have.
Also, very often when going for a 'bass mod' the bass rolls off below 100hz.
I feel like I achieved what I set out to accomplish.

• Open the rear ports (remove plastic covering the vents)
• Inside of cups covered with adhesive felt - left just the bottom vent open.
• Aftermarket Ori pads
• Paxmate around driver front (make sure to leave the side vent open)
• All stock driver damping removed (this was causing HUGE bass energy around 100-200hz)
• Replaced stock damping with micropore tape, leaving middle and top vents open
• 'Mad dog'esque adhesive felt on back of driver
• Smaller adhesive felt rectangle on front of driver
• 0.30g of Twaron Angel Hair acoustic filler
• One circle of acoustic filler (arctic cotton/thermolam/whatever you have) inside the ear pad - this does 2 things - treble attenuation and 'spacer' that drastically improves sub-bass response.
• DIY suspension headband - makes the biggest improvement, obviously.




(Dip at 4kHz is a well known artefact when measuring closed-backs with miniDSP EARS.)

Replying to myself here ...

I updated the mod to bring down the mid-bass.
Increased quantity of Twaron Angel Hair from 0.30g to 1g

New mod with 1g of angel hair -

Old (white) vs New (purple)

Finally got rid of that last final 'bloat' that plagues SO many of these Fostex mods.

 

[schmalgausen]

Just bought another T50RPMK3. I used to own one early produced and then sold them. The 1st difference is gold-plated connectors on the new cable, old were white-plated. The 2nd possible one is soft cushions like MK2 leather, I guess previous were significantly harder. 2015 vs 2020. Am I right?

 

[smorgar]

Just bought another T50RPMK3. I used to own one early produced and then sold them. The 1st difference is gold-plated connectors on the new cable, old were white-plated. The 2nd possible one is soft cushions like MK2 leather, I guess previous were significantly harder. 2015 vs 2020. Am I right?

Yes that is correct regadring the padding. The MK2 had a rubber sleeve and the MK3 has pleater with some padding.
I have used the padding from Sennheiser HD600 to make it super comfy.

 

[schmalgausen]

I was talking about early MK3 and nowadays MK3.

 

[smorgar]

Have had a break from the T50rp for a few weeks. Replaced the pads on my HD600 and got a HD660s to do a HD600 vs HD660s comparison... (I liked the HD600 better).
Today I put on my T50 again to do some gaming since the imaging is amazing and therefore the positioning is simply mind blowing. The T50 are so much better, of course depending on mod but the sheer speed of the drivers is just magical.
Song recommendation: THUMP - I'm Pissed
Both funny and quite fast and complex to make the speedy drivers shine

 

[volly]

It's been a really long while....but the T50rp's are still bonkers good!

I bought the Massdrop Version upon release years back and just shelved them as you do in this crazy hobby! I remember my copy having a bad connection in one ear cup so I just gave up on them at the time!

Well the other day I found them in the closet and decided to open them up and fix them! Found the problem, negative wire come completely off the soldering. So I went and grabbed my soldering iron and soldered the cable back on! I remember I had modded them before with some cotton fill and clay putty in the back of the driver baffle. I removed the cotton and gave it a clean out. Put them all back together and grabbed some Dekoni Hybrid pads that I had laying around for my D2000's. I hooked them up to my SP200/Theta DSP Prime II and away we went. Hours later...I was in love again! It's like getting in your old sports car you once had rusting in the shed....you take it for a drive and it just comes a live. The Fostex Planar drivers just has something special about it....fast...clean...accurate but not overly and not under but just enough! Imaging is simply insane for the price you pay for these things now! Not overly wide but deep as heck....it just draws you in deeper and deeper and you're greeted with all these sound cue's all around your head and especially inside your head! It doesn't feel too claustrophobic as you feel as though you are float in the ether with all this music in and around you....it's uncanny!

I've playing some Apex Legends with the T50's and I just get a great sense of direction than most other headphones, it's good if not great! There is a peak in the upper treble area but that can be fixed with some more dampening but I kinda like it....S sounds come off a tad zingy but is still informative and adds a bit more air! The mid bass on my mod is fairly neutral but I still get a little rumble from the lower bass so it's fairly even down there. Really gives the music good body and helps the midrange shine through. The mid's are delicious, something like the 600 or 650 by Sennheiser but the better imaging just creates a sense of liveness in the mid's...really great here!

All in all....I keeping them in the rotation for a while and will go up on the rack later! I may grab the T60rp's as they have been on the wish-list for a long time coming. Going back to the T50rp's is like coming home again. Love it!

 

[Sam21]

Do T50RP ear pads fit other headphones ? if so, which ones ?

 

[DeweyCH]

Ayyyyy, I finally got around to finishing rewiring my T50rp Mk IIIs. Nothing too crazy - they have a ZMF leather strap and lambskin pads, finally put mini XLR ports in each cup to balance them.

Nothing out of this world but it's nice not to have to worry about that stupid orange horrid cable. Good gravy they're bassy.

 

[IvanDrago]

T20RP MKII mod inspired by @GREQ
Mr Speakers alpha pads + headband
Hirose connectors

Meanwhile the alpha pads are pretty battered, two seams are popped. Maybe i´ll try another mod with pads from brainwavz.

 

[p1zzap1e]

Getting a pair of t50rp on Monday, my first pair of “better” headphones and I choose it because of the flexibility in modding. Going to start listening on them without mods, then with a pair of zmf lambskins I also ordered.

It’s going to be fun trying to mod them to how I think I want them. Mostly gaming, but also music of course. Got some blue-tac, acoustic felt and tape at home.

A question to the experienced modders: most guides say that blue-tac/clay should be on the baffle, and acoustic felt on the inside/back of the cup together with tape and cotton. But I have also seen and read about people using clay/blue-tac on the inside of the cup where most guides say to use acoustic felt. Anyone who can give an simple explanation of the differences? Maybe a bad idea to use both blue-tac on the baffle and the back/inside of the cup.

 

[kingoftown1]

They have two different purposes -- the blue-tac is for addressing mechanical vibrations/resonance. Felt/cotton are for acoustic damping.

 

[p1zzap1e]

They have two different purposes -- the blue-tac is for addressing mechanical vibrations/resonance. Felt/cotton are for acoustic damping

Yeah I’ve read that, but because of my lack in experience and knowledge I don’t understand the differences it would create sound wise and why someone would recommend to use clay instead of acoustic felt in the back of the cup as felt seems to be the most used material. I have acoustic felt at home and plan to use it, but when I saw some recommendations to use clay instead I started to wonder what differences it would give the sound.

 

[VanHai]

Yeah I’ve read that, but because of my lack in experience and knowledge I don’t understand the differences it would create sound wise and why someone would recommend to use clay instead of acoustic felt in the back of the cup as felt seems to be the most used material. I have acoustic felt at home and plan to use it, but when I saw some recommendations to use clay instead I started to wonder what differences it would give the sound.

If you have time and budget, i highly recommend use acoustic felt. I used Pax-mate for all my modded, inside the cups and baffles, it takes longer because you have to cut them into small pieces for both the cups and baffles. You can use the clay, it is cheaper, but if you keep the the headphones longer . The air will get inside the cups and eventually dry out the clay, and crack will develop. I had this experience with the Argons ( yes, Modhouse).

 

[volly]

Yeah I’ve read that, but because of my lack in experience and knowledge I don’t understand the differences it would create sound wise and why someone would recommend to use clay instead of acoustic felt in the back of the cup as felt seems to be the most used material. I have acoustic felt at home and plan to use it, but when I saw some recommendations to use clay instead I started to wonder what differences it would give the sound.

Just as @kingoftown1 explained, you want to load up on the back of the drivers where the channels are. It's to firm up the speaker wall so-to-speak, I wouldn't personally put clay/blue-tac on the inner cup but I've used sound-dampening foam there with some degree of success. This, in combination with pax-mate or whatever you want please is to reduce any reflection, reverb, all that kinda stuff in the cup! Think of these mods as a kin to treating your room for you speakers, you want to reduce as much reflections as possible by "treating" the room, putting carpet or a large mat, foam panels on the walls etc. However, you can go too far in the other direction where things can seem 'too-over dampened!" as well.

The rule of the thumb is to do a little mod then listen, then do another and then listen, you'll slowly start to see what does what, this is half the fun in modding the T50's! And just plan on reversing a mod if it doesn't suit your taste.

Another tip is to take very, very good care of the screws when you disassemble the ear cup to get to the inside. DO NOT over tighten or rush that part, take very good care of the screw heads as they can be delicate and soft! Also Be aware of the left-side cup, as you disassemble, watch for the wiring inside the cup as you pry it open, you could inadvertently yank it too hard and break the solder joint!

Good luck, Have fun!

 

[IvanDrago]

this is half the fun in modding the T50's!

but could also be a nightmare

@p1zzap1e
Mayflower uploaded a modification video for the T50RP MK3 a while ago. In my opinion a good starting point.