[proid]

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And that also doesn't stop you from having cavities in the cardboard itself, double win! There's also a menton of a tapered cavity in that article, should be even better as it would work for a range of frequencies.
 

That's an excellent idea but it's not easy to do 

 


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I  am also interested, this second photo looks very different than your first one showing the cardboard in the cup. Could you please elaborate your construction steps with additional photos? I think you may have come up with a valuable addition to the mod mysteries. I have googled helmholtz resonator and trying to apply the theory to headphones is beyond me.
 
 

 
Just image a helmholtz resonator is a close, air tight box with openings
 


 
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Oh, another question. Do you still have the stock felt covering the 4 bottom vents in the cups? Any tape over the vents on the outside of the cups?

In my config, stock vent felt sound best and i cover the vent on the outside 3.75 slot. If you love bass, you should definitely try this. Listen to "Infected Mushroom" have never been better 

 

 

[DeathDomokun]

Has anyone thought of doing a detailed yet concise summary of the mods they did?

 

[elwappo99]

I can't find any definitive information on the solder of these. Is the solder on the t50rp aluminum only? The t40's are, but I can't seem to find information about these.
 

 

[Taowolf51]

Just finished my mods, and they're beginning to sound great! Had some issues at first, and the mods themselves took far longer than I expected.
It's surprising how "meh" the T50rp's sound out of the box, the difference with the mods is damn impressive. They're not a revelation, and they're not a replacement for my D7000's, but they're *totally* a replacement for my Pro 750's as my portable can. If I could get them to be a bit clearer and a bit more aggressive, and tone down the upper mids just a smidge, they'd be perfect.
 
They're great for stuff like rock and metal, and the tightness is great for electronic music. I did notice that these are more selective when it comes to mastering and bitrate.
 
And something strange I noticed that has been bothering me. While these headphones seem detailed, they don't sound very "clean" so to speak.
 
I did Magick Man's version of the Rastapants, and thanks a bunch to Magick Man for all his help!

 

[kalbee]

I thought the Helmholtz resonator had to be completely sealed, except where the sound waves enter?
Guess I best go get those class notes I have stored somewhere.
Actually, I don't even know if it's the same thing as that. The absorber I wanted to try making works along the same principles, but some simpler way of making it would be to have a flat surface with holes of various sizes for different frequencies. Just don't know nor remember if the sides of the chamber should be sealed, and whether or not that thing is a Helmholtz resonator.
 
Thought glad someone confirmed it works
This 'spring break' is nothing but being absolutely busy >.>

 

[CosaNostra]

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With regard to the beyer velour pads, (and please forgive me if this was answered earlier) I know these pads either come from Beyerdynamic in the DT770 variety or DT880/990 variety, and I guessed that since the DT770 are a closed-back phone these would be the natural swap for our T50RPs, but I noticed earlier in the thread people were saying they were swapping to the DT880/DT990 velour pads, so is there a specific reason for this?  Has anyone experienced the difference between these two types of velour when swapping to T50RPs?  
 
I should also note that my reasons for wanting to change pads from the stock Fostex is first and foremost to increase comfort (my TP1s have Wenge wood cups and this makes them rather heavy) and secondly to (hopefully) create a better seal for bass, although as long as I didn't lose bass and increased my comfort while doing so, I would probably be happy with that.   I know each individual T50RP is somewhat subject to mods done on it and each change made can have a large impact on the overall sound sig, which is why I'm leaving the pad swapping itself to Smeggy to perform and ensure I don't mess it up and ruin my cans.  

 
Anyway thanks in advance for the help!  This thread has been an enormous aid in figuring out what these various mods are and how they work to some degree, although I'm still not brave enough to open my T50RPs and start digging around in there.  Maybe when I have a spare.  

If you want to make them more bassy try the J-Money beyer pads. They are super deep, fairly comfy and add a ton of bass quantity. Unfortunately for me, the rest of what they do doesn't suit my tastes so I have reverted back to the O2 pads. If you want a cheap solution though, try the SRH 840 pads, they are supposedly very good. I was almost sure they wouldn't fit my needs, but I am almost ready to reconsider and pick up a pair to see what all the fuss is about.
 
P.S. Haven't tried the velour pads off my 990, will do that and report back.

 

[wje]

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Has anyone thought of doing a detailed yet concise summary of the mods they did?

I thought the purpose of the Wiki page was for this purpose?
 

 

[hans030390]

Proid's mods got me thinking, which led me to testing out this easy mod (someone might have already tried this):
 

 
I took some cardboard, and I cut it up into the strips above in such a way that when one layer of the cardboard is peeled off, you're left with two "bumps" that run along the strip. I was also considering cutting out the middle section of the two long strips and replacing that empty spot with pieces facing horizontally instead of vertically. I might test that at a later date.
 
How does it sound? I don't know. It sounds like it has an easier time with bass extension than before and perhaps better bass detail in general. Sound might be a bit smoother overall without losing any detail. Everything seems to be just about where it needs to be. Sinegen seems to confirm better bass presence, but my ears could be fooling me! They've done it before...take my words with a grain of salt.
 
Still, I'm really liking what I'm hearing! 
 
Don't worry if the middle layer of cardboard comes detached on the edges when trimming down the strips to fit. As long as the general shape stays in place, it should be fine.
 
For anyone who may be interested in my full mod lineup, it's basically just a slightly modified RP2 840:
 
1. Silverstone acoustic foam lining the cups.
2. Those cardboard things as you see them.
3. Stock vent felt in place, no vents covered on the outside.
4. 6 cotton balls teased apart and stuffed in the cups.
5. Non-drying modelling clay loaded in the back-side driver baffle.
6. Acoustic foam applied atop the clay.
7. White driver felt/paper removed. Back of driver is "naked" except for the middle square, which is uses duct tape as a reflex dot.
8. Dynamat on the ear-side baffle. Small hole next to driver is sealed.
9. Acoustic foam on top of the Dynamat.
10. 840 earpads
11. Suspension headband mod and main headband bent inwards to increase clamping force.
 
I'm not claiming these mods are tweaked for this particular cardboard mod. I just wanted to put this quick idea up. I haven't really tried tuning anything around it, but it sounds good so far like this. Really good.

 

[Nevod]

 
 

If you want to make them more bassy try the J-Money beyer pads. They are super deep, fairly comfy and add a ton of bass quantity. Unfortunately for me, the rest of what they do doesn't suit my tastes so I have reverted back to the O2 pads. If you want a cheap solution though, try the SRH 840 pads, they are supposedly very good. I was almost sure they wouldn't fit my needs, but I am almost ready to reconsider and pick up a pair to see what all the fuss is about.
 
P.S. Haven't tried the velour pads off my 990, will do that and report back.

Some people say gel pads are even better. I have only tried the gel pads, and can say they are very good. But I don't have anything to compare.
 
 


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Proid's mods got me thinking, which led me to testing out this easy mod (someone might have already tried this):

They probably act as diffusors that way. One also can pinch holes to chambers formed by cardboard's middle layers, that would also work as resonator, but edges would have to be taped.
 
Again, on the Paxmate/Silverstone materials. From the photos, both of them look more like closed-cell foam.. I guess that they are intended primarily to reflect sound inside the computer back and not let it reach the case panels, instead of absorbing it, absorption is 'secondary' in them. Open-cell foams should work better, IMHO..
 
 

 

[hans030390]

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They probably act as diffusors that way. One also can pinch holes to chambers formed by cardboard's middle layers, that would also work as resonator, but edges would have to be taped.
 
Again, on the Paxmate/Silverstone materials. From the photos, both of them look more like closed-cell foam.. I guess that they are intended primarily to reflect sound inside the computer back and not let it reach the case panels, instead of absorbing it, absorption is 'secondary' in them. Open-cell foams should work better, IMHO..

Right, a diffuser is more or less what I was going for. For some reason, the cardboard idea never crossed my mind until I saw what proid was doing! It's stupid simple, really, and I figured it might be an interesting material to investigate for modding purposes.
 
The Silverstone acoustic foam looks open-cell to me. I think it's been squashed quite a bit in most of my photos, making it look differently than it should. I could be wrong, though.
 

 

[proid]

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Right, a diffuser is more or less what I was going for. For some reason, the cardboard idea never crossed my mind until I saw what proid was doing! It's stupid simple, really, and I figured it might be an interesting material to investigate for modding purposes.
 
The Silverstone acoustic foam looks open-cell to me. I think it's been squashed quite a bit in most of my photos, making it look differently than it should. I could be wrong, though.
 

Glad that cardboard work for you 

. I think you should also try the resonator because from what i read, it's the most effective way to absorb low frequency 

 

[Goras]

Might by helpfull. Akasa closeup.
 

 

[dyna10x]

My fostex have been resurrected! I scraped the covering off the copper traces and got a complete circuit with my multimeter. So I purchased some wire glue and tried attaching the wires to the bare traces with it. This did not work so feeling rather desperate and willing to try anything I dismantled the driver to expose the diaphragm and stuck the wires onto the very edge of the bare copper traces on the diaphragm with a tiny piece of scotch tape and I had a working driver once again. Seems to work fine so far. What a relief. I also added a DIY cardboard resonater like Proid's and I do believe I can hear an improvement in the bass. I am also using a dual layer of rockwool and polyfill in the cups and these headphones are sounding great at the moment.

 

[CYoung234]

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Is that Paxmate or what?

Nevod, yes that is Paxmate, but there is also Dynamat under it in the cup bottom only. The Dynamat I used was the original, which has no gel or foil face. I also have both Paxmate and Dynamat on the ear side surrounding the driver opening out to where the pads sit.
 
 

 

[Nevod]

Here is the picture of Biplast. Sorry for low quality, that's the best I could squeeze out of my cam. It should be capable of more than that though, I think.

This foam is much more open than Paxmate. 2-3 top layers of cells seem not to have any walls at all, in the deep there are walls.