nick n said:

  I think Transpore may be too reflective, in my experience Micropore is less so and filters things nicely, not tried it on  the driver rears that close however.  Some folks have done so directly on yamaha driver rears but leaving some areas still open.

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bluemonkeyflyer said:

  I'm glad the diaphragm worked for you. If I remember correctly, you removed the rear side stock damping membrane from your drivers. Doing so "let's them Fly" uncontrolled with massive Boomy Bass Bloat, midrange muffling, and squashed treble. In my experience, trying to regain lost ground after this irreversible modification is a cluster FUBAR. I posted some mods that work pretty well in the first post of this thread and the Naked Driver Mod in the T50RP WOW thread.
 
I don't hear any effect with the stock ear side dust cover removed or left on. It's Ultra thin and very air permeable.
 
I've used the cotton pads, like the ones I used to cushion the diaphragm I sent you, successfully as damping material in the All Paxmate Lattice Mod and the Balsa Wood Lattice + Paxmate Lattice Mod. In each of these, I left a 35mm x 35mm "nest" (an opening in the lattice work) directly over the rear of the drivers. I cut the cotton pads to fit this space with good results.
 
3M Transpore Tape is perforated, clear plastic tape that allows for controlled air flow
.
3M Micropore Tape is not perforated and lets minimal, if any air through. It's advertised to "breathe" when used on skin so maybe it breathes a little bit; still has to make it through the adhesive. It's opague white paper tape. You can remove some/all the adhesive by soaking strips of it in acetone and rubbing off the loosened adhesive with your fingers. Let it dry and you may have a more air permeable paper you can glue into place. Another method is to remove the adhesive, let the Micropore dry, then cut to size. Next, cut another piece of Micropore in the shape of a picture frame that slightly overlaps the perimeter of the non-adhesive Micropore. This may allow you to tension the non-adhesive piece over the back of the driver. Others have tried coffee filters, dryer sheets, etc. 
 
I recommend using masking tape to attach baffles to cups when modifying and tuning. This is the best way to prevent stripping the cup threads. For one method to repair stripped cup threads, look in Post #1 of this thread. There's a Table of Contents tab for this.
 
RE: Opening/Closing modification cycles... I feel your pain and applaud your determination.
 
Good Luck!

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zgliszcz said:

Yes, but for some reason any config I tried with stock damping didnt really work for me. It was long time ago and probably I did something wrong. But it was medium freq leak that made me decide to remove stock dampening. Also I remember that I tuned them once to some amazing results and it was mixture of felt and some kind of kitchen rag with tiny holes behind drivers. So far I tried lot of similar variants and I cant hit the right set again. I think I will try to change fill inside my pads and see if that will change something. About black dust cover, I remember that I had sibilance on some configs without it when I was using stock dampening but with felt it didn't make so big differences. Currently I glued some sort of felt on earside of baffle to remove earchamber reflections and maybe that killed my config. Tomorrow I will check complete naked driver, I'm sure it wont sound good but I want to check how it sound now naked. If I had not heard them sound so great I wouldn't believe they can sound like that but now I really want to achieve similar results or go further.

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bluemonkeyflyer said:

I call drivers with the white damping removed "Naked Drivers." Attempts to tame their wooly bass refers to the Naked Driver Mod(s).

Keeping records pays off. I take photos of everything I do and measure results from new materials, configurations, and tuning. This makes it easy to check what I've tried in the past that worked vs failed.

For ear side reflections, try felt or acoustic foam around the driver opening on the ear side of the baffle. Changing pad type can tune your mod configuration: foam density, leather vs velour, sealed vs vented/perforated, size and shape, angled, etc. Small strips of foam on the inner walls of pads work. Thin cotton and other materials over part or all the ear side of the driver may help control sibilance or tame a treble peak. BMDs (prepared acoustic foam) over part or all of the ear side center grid space works, too.

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zgliszcz said:

 
Hi Keith,
I was moding them for about 4 weeks in hotel room which was bit "guerilla way" I was using my sansa clip with rockbox and Corda 2Stepdancer as source (thats why I didnt made any photo) and at home I was using e-mu tracker pre plugged to some cheap marantz which doesnt have that good headphone amp but did work well with my k701 I believe it was different source and somehow 2stepdancer with 15volts works better with fostex... Also my earpads were bit squished after laying for few weeks when I was waiting for diaphragm replacement. I worked bit on them yesterday and sound changed pretty nicely. they got some cotton scraps inside and Im planning to remove it and put some foam inside (actually I will try to squeze inside 2 pairs of fostex pads and some piece of my converse shoes... yup) and I need to finish wave guides, I know you waiting for them. Will try to finish them today after work.
 
Man seems like you tried all possibilities already

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peterek said:

Hey BMF, what do you think about naked drivers and cutting the cups up a little to make them open? I was thinking about trying it but I don't want to wreck a pair of cups doing it and it sounding bad.

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bluemonkeyflyer said:

 
 
For T50/40/20 RP in stock cups:
 
The more you vent the back wave, the more boomy the bass becomes. Doing either one is bad. Doing both is much worse. You will spend a lot of time trying to tame it.

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hemipowered007 said:

Do it Casper!! They made the t500 work so can you!

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hemipowered007 said:

Less thinking more doing! It has to be possible. If I had knew what I was doing I'd try it. It'd be pretty easy to make wood open enclosures for these.

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hemipowered007 said:

That's what I meant, making simple full open wood enclosures with enough space to dampen IF necessary. I wish I had time to try it. Wouldn't be pretty but I could make cups pretty easily for these I think.

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bluemonkeyflyer said:

  Re-Measured LCD2 dimensions for Wave Guides
 

 
Rear Side of LCD2:
 
The height of the Stators and the Openings = 5 mm.
 
The width of the Stators and the Openings = 44 mm.
 
The height from the "floor" to the "ledge" where the grille sits = 7 mm.
 
For simplicity, I think the upper opening could be made 8 mm from side to side and the narrow opening at the bottom could be made 3 mm from side to side. 
 
The Ear Side is the same except it's inverted 180 degrees.

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