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

[Hutnicks]

Check McMaster-Carr for inserts.

Check Post #1 of FIMM for info about how to use superglue and a 2mm drill bit to repair stripped cup threads.

FIMM???

 

[nick n]

Fostex Incremental Mods & Measurements

 

[Hutnicks]

  Fostex Incremental Mods & Measurements

Thanks. Now why could I not figure that out. I was wondering where that tutorial on the crazy glue screw fix was at.

 

[DatGameh]

Scuse me guys
May I ask for some advice here?
Sorry to disturb a 755 page thread about a person's reaction to the T50RPs, that has been left quiet for three months.
 
In a month, I will be getting my own T50RP mk3 to enjoy.
I would like to experiment with some mods of my own, since I live in a country with very few materials used in many mods.
So far, the only thing I can find here is Transpore and Micropore. Anything like sound dampening foam is nowhere to be found.

Before I start, I would like to know the basic objectives and concepts when modding this headphone.
This is what I know so far:
 
-By default, the T50RP has recessed sub bass and spiky highs.
-Reflecting sound waves from the ear cups can lead to weird mids and highs (resonances)
-Vibrations in the baffle can reduce bass
-The thin fibrous film on the driver's back is used to stabilize the sound from distortions, and control bass and treble
-The vent is used to control the bass
-Earpad is completely disposable
-The drivers work best when the ear is near the driver
-They are pretty hard to drive

And, from these, I will do these to improve the sound
-I will add thick rebond foam (only sound dampening foam available) to the back of the earcup to absorb sound waves, but leave enough breathing space for the vent.
-I will roll up a cardboard strip like this, to dissipate the sound waves. This is done to compensate for the rebond foam's low density.
-I will add Plasticine to improve the bass response.
-I will use Shure 840 earpads, along with this sock mod (using a cotton/foam circle to secure it instead of cardboard) to make it less sweaty and more comfortable, while keeping the same sound isolation. Hopefully, this will absorb some of the treble too.
-I will use a leather belt to create a suspension headband to improve head comfort
-I (might) use a V-Moda cable
 
Stuff I will keep stock
-Driver dampener
-Earcup (no closing of vent or cutting of anything)
-Overall visual aesthetic
 
Does anyone have an advice for improvement, or corrections for the mistakes that I might have made?
Thanks!

 

[FullBright1]

   
 
-By default, the T50RP has recessed sub bass and spiky highs.
 
 
Does anyone have an advice for improvement, or corrections for the mistakes that I might have made?
Thanks!

 
Burn them in for 2 weeks before you decide to mod.
 
Go here if you need music
 
http://www.head-fi.org/t/826363/affordable-happiness

 

[DatGameh]

   
Burn them in for 2 weeks before you decide to mod.
 
Go here if you need music
 
http://www.head-fi.org/t/826363/affordable-happiness

 
Alright.
I'll do that, and thanks for the music, by the way!
 
Anyways, besides that, basically, I got the concepts and all correct, right?

 

[c61746961]

-By default, the T50RP has recessed sub bass and spiky highs.

Yep.

-Reflecting sound waves from the ear cups can lead to weird mids and highs (resonances)

In a much smaller sense than it appears. The mk3 is pretty decent-sounding and it features zero cup dampening. I wouldn't go overboard on this.

-Vibrations in the baffle can reduce bass

Same as above, if anything, dampening the baffle will lower distortion in the bottom octave. I would this as a finishing touch if needed.

-The thin fibrous film on the driver's back is used to stabilize the sound from distortions, and control bass and treble

It's there for impedance-matching the driver to earcup-to-earpad volume. This greatly affects the resulting FR. Don't touch it until you're happy with the earpads and cup venting.

-The vent is used to control the bass

Yep, blocking it will limit the 'available' volume for higher-wavelength signals, hence killing the sub-bass. And vice-versa.

-Earpad is completely disposable

Some people are happy with it.

-The drivers work best when the ear is near the driver

Seems to be the consensus.

-They are pretty hard to drive

Truth.

And, from these, I will do these to improve the sound
-I will add thick rebond foam (only sound dampening foam available) to the back of the earcup to absorb sound waves, but leave enough breathing space for the vent.

Don't forget to leave some space behind the driver.

-I will roll up a cardboard strip like this, to dissipate the sound waves. This is done to compensate for the rebond foam's low density.

That won't do ****.

-I will add Plasticine to improve the bass response.

Leave this for until you're happy with the frequency response.

-I will use Shure 840 earpads, along with this sock mod (using a cotton/foam circle to secure it instead of cardboard) to make it less sweaty and more comfortable, while keeping the same sound isolation. Hopefully, this will absorb some of the treble too.

You will lose some isolation but a thick sock will probably help with the highs. You are increasing the impedance (depending on the textile/thickness) on the ear-side so you will have to compensate with blocking the baffle ports or adding less stuffing inside the cup to achieve the bass balance you desire. If the bass is still not enough you will have to add more vents to the dampening paper. Try the earpads first, then you go inside the cups. Pads will change the sound more than anything.

-I will use a leather belt to create a suspension headband to improve head comfort

That will help.

-I (might) use a V-Moda cable

The V-Moda cable leaves a gap on the cup, which is effectively a vent. Try making a seal around the jack inside the cup or you will end with bass imbalance.

Stuff I will keep stock
-Driver dampener
-Earcup (no closing of vent or cutting of anything)
-Overall visual aesthetic

I've done the same.

Good luck!

 

[DatGameh]

Thanks for your long and detailed answer! I really appreciate that you took your time in writing your response

Although you answered many of my questions with (great) detail, it raised a few more questions
 

 It's there for impedance-matching the driver to earcup-to-earpad volume. This greatly affects the resulting FR. Don't touch it until you're happy with the earpads and cup venting.

Forgive me, but I don't really understand the concept of matching the impedance to the earcup-to-earpad volume.
May I know what it is in a nutshell?
Also, if I want to modify it, what are the general guidelines? Like: holes increase bass response, porous tape filters bass, restrictive tape makes sound less "sharp", etc.
Just out of curiosity.
 

 -I will roll up a cardboard strip like this, to dissipate the sound waves. This is done to compensate for the rebond foam's low density.
That won't do ****.

Uh, why so? I dunno, but I just find it makes sense, logically :|
 

 You will lose some isolation but a thick sock will probably help with the highs. You are increasing the impedance (depending on the textile/thickness) on the ear-side so you will have to compensate with blocking the baffle ports or adding less stuffing inside the cup to achieve the bass balance you desire. If the bass is still not enough you will have to add more vents to the dampening paper. Try the earpads first, then you go inside the cups. Pads will change the sound more than anything.

So essentially, the sock will absorb the bass, right? Alright, then.
The baffle ports are the small round holes that make slight bumps  around the plastic frame that hold the driver, right? The unfilled holes in this picture:

 
Also, instead of filling up the baffle port, is filling the baffle mold spaces with plasticine instead enough? I'm not sure I want to fill tight spaces that might make it hard to remove the plasticine.
And when you said add less stuffing, you mean the foam in this case, right?
 
Alright, that's all.
Thanks again!

 

[c61746961]

Forgive me, but I don't really understand the concept of matching the impedance to the earcup-to-earpad volume.
May I know what it is in a nutshell?

To make it behave more linearly. Think a more linear frequency response.

Also, if I want to modify it, what are the general guidelines? Like: holes increase bass response, porous tape filters bass, restrictive tape makes sound less "sharp", etc.
Just out of curiosity.

Little dampening = more bass, wonky mids, recessed treble. More dampening = less bass, more linear to elevated mids, sometimes spiky treble. I'm not sure about reflections, but the least sharp T50RP I've modded doesn't have the stock dampening paper, it has very high density polyurethane foam (makeup applying pads a la nick n mods) instead. It's still kinda sharp.

Uh, why so? I dunno, but I just find it makes sense, logically :|

The carboard is rather transparent acoustically for a lot of problematic frequencies. I'd rather go for fibrous / spongy stuff for wideband absorption.

So essentially, the sock will absorb the bass, right? Alright, then.

It will compromise the seal against the face letting some pressure escape, less pressure = less bass. It all depends on the textile's thickness.

The baffle ports are the small round holes that make slight bumps  around the plastic frame that hold the driver, right? The unfilled holes in this picture:

Nope, that looks like a mk2 variant. The baffle ports are only present on the mk3 variants, behind the grey foam on the ear-side of the baffle, around the well. There are 8 ports. Blocking them will effectively increase the pressure on the ear-side of the baffle.

Also, instead of filling up the baffle port, is filling the baffle mold spaces with plasticine instead enough? I'm not sure I want to fill tight spaces that might make it hard to remove the plasticine.
And when you said add less stuffing, you mean the foam in this case, right?

Plasticine helps stiffen the baffle, but it comes already coupled to the earcups via binding posts thus fairly stiff.
I meant less stuffing directly against the driver; it's very easy to apply too much stuff and add further dampening to the driver's movements instead of just absorbing some of the backwave.

Alright, that's all.
Thanks again!

You're welcome.

 

[ShadowStryker24]

Soooooo, Im thinking of picking these up. Would the FiiO E10K happen to be able to drive them? Im really interested int their sound quality and they seem quite awesone

 

[rogerartman]

Hello Magick Man,
I'm new to innerfidelity.com and am utterly blown away by the measurements on your modified Fostex cans! That said, I think I entered at "mid-mod" on your mod explanation. Would you take it from the top and go through the entire process? What's done on driver baffle is quite clear, but the rest of the mod is unclear to me, i.e., the white sheets, the hole in the baffle. Please help an old newie out!
Thanks,
William Greywolf

 

[sman789]

Been content with my T40s since I got them about a year ago. Only added some cheap velour pads and a hand made comfort band that snaps on.
Found a nice cable on Ali and also have a smartbean whenever I need wireless.

 

[hemipowered007]

Posted in other t50 mod page as well, but so excited I'll post here too. Almost done, needs to be fitted for hifiman frame set screws, smc port and 2 bass ports. Then lots of Danish oil+top coat finish work. I made a baby teether recently out of limba, did Danish oil then 6 coats of polycrylic sanding w 800 grit in between and got a nice smooth finish. I read doing around 20, then letting cure for around 2 months, will net an extremely durable plastic like finish. People use it for surfboards, but anyways. Not going to touch the inside of the cups at 1st, definitely no oil or sealant. I created the baffles to be recessed to give more air between ear and driver. May be a bad idea I don't know yet. But, the baffles are quick to remake, they are turned from maple, outer is limba. Next will be spalted maple or cocobolo w a white streak, or something fancy. My father in law has done all the turning just with me letting him know what I want and how it should all come together. I've had this idea for years and I'm finally almost there. I havnt heard the t50 in so long I don't even know what to expect and probably should buy a stock set for comparison. Any suggestions for ANY internal mods from here will be openly welcomed!

 

[Paladin79]

Very nice work!

 

[hemipowered007]

Put them together last week just to check on fit. Still working on the finish, and waiting on my smc connectors. Getting real close to finally being done.