Fostex T50RP Incremental Mods and Measurements
Sep 24, 2012 at 6:10 PM Post #121 of 2,832
Quote:
 
 
Some heads too, I would imagine. 
wink.gif

LOL!  And that comment about "stirring up the Yankees?" What about all us Southern Rednecks?!  Don't make me open up a fresh can of "whoop ass!" 
 
Sep 25, 2012 at 1:19 AM Post #123 of 2,832
I'm about to sleep, but it seems that the Grodan Rock Wool is the single most effective modification, especially with the 840 pads. You say I should buy cheese cloth, and tape it to the sides with Transpore?
 
Without mods, this headphone is very vocal centric, especially male vocals. Distorted guitars suck.
 
Sep 25, 2012 at 6:12 AM Post #124 of 2,832
Quote:
I'm about to sleep, but it seems that the Grodan Rock Wool is the single most effective modification, especially with the 840 pads. You say I should buy cheese cloth, and tape it to the sides with Transpore?

Without mods, this headphone is very vocal centric, especially male vocals. Distorted guitars suck.


Cut two oval gaskets slightly larger than your rock wool. You can use gauze from the drug store. Place one in the cup and trim to fit. I used two pieces and overlapped them since my roll of gauze was not wide enough to cover the entire cup floor.

Install your rock wool over the gauze and cover it with the other piece(s) of gauze. You don't need to tape down the gauze though I suppose you could. When you close the baffle to the cup, you will need to apply some pressure to force the back of the driver down into the rock wool. I like to avoid straining the driver by pre-compressing the rock wool with my fingers. Be careful you don't push too hard against the wires soldered to the back of the jack. Once compressed, the rock wool crumbles but still works just fine. The gauze simply keeps the rock wool from fouling up your cups and drivers if you decide to remove it to make some tuning tweaks.

I agree rock wool was the single most effective mod when used with Shure 840 pads. Even so, I added ~ 5x70x70 mm cotton overlaying the rock wool, Newplast (or plasticine) flush mass loaded in the baffles, and 40x40 mm stiff felt over the stock white driver material. I think adding these three readily available materials improved the sound quality. I like what I hear but you should try it both ways and decide for yourself.

Note: more detailed configuration steps for Rock Wool mods are listed after Graph #55 in Post #1.
 
Oct 2, 2012 at 8:16 PM Post #125 of 2,832
Wow, this is incredible! Thank you so much for keeping you process open and contributing such a wealth of data to the modding community! I just bought my set of T50rps, and I'm excited to get cracking on them. Although I realize that FR charts aren't everything, I'm really impressed by how close these mods bring the T50s to the LCD2s. Exciting stuff!
 
Oct 14, 2012 at 9:20 PM Post #126 of 2,832
Just finished my first round of modding.  Damn what a difference!
 
I'm quite surprised at the upper range detail that was missing before, I am a Grado/Hifiman HE-300 owner so that was something I was prepared to miss, but I don't at all so far.
 
 
One thing, I didn't have any cotton available but wanted to hear them.  I used a small amount of "fluff" from one of my dog's toys but it doesn't seem to appear as dense as the Rite Aide but I didn't use much either.
 
I can't see the images unfortunately, but will the proper cotton improve the mids?  That is one thing I'm not liking right now, but I'll keep tweaking of course :)
 
Oct 14, 2012 at 10:12 PM Post #127 of 2,832
Just finished my first round of modding.  Damn what a difference!

I'm quite surprised at the upper range detail that was missing before, I am a Grado/Hifiman HE-300 owner so that was something I was prepared to miss, but I don't at all so far.


One thing, I didn't have any cotton available but wanted to hear them.  I used a small amount of "fluff" from one of my dog's toys but it doesn't seem to appear as dense as the Rite Aide but I didn't use much either.

I can't see the images unfortunately, but will the proper cotton improve the mids?  That is one thing I'm not liking right now, but I'll keep tweaking of course :)


Rite Aid Natural Absorbent Cotton is no longer available. London Drug Absorbent Cotton and US Cotton Absorbent Cotton Roll work almost as well. Links are at the bottom of my first post.

With the proper amount of cotton and fiberglass as described in post one, following Graph 55, the mids sound sweet.

Fiberfill has never worked for me no matter how much/little I used and in many configurations.

Keep trying different amounts. A little more or a little less can be the difference between success and "also ran."
 
Oct 14, 2012 at 10:35 PM Post #128 of 2,832
Quote:
Just finished my first round of modding.  Damn what a difference!
 
I'm quite surprised at the upper range detail that was missing before, I am a Grado/Hifiman HE-300 owner so that was something I was prepared to miss, but I don't at all so far.
 
 
One thing, I didn't have any cotton available but wanted to hear them.  I used a small amount of "fluff" from one of my dog's toys but it doesn't seem to appear as dense as the Rite Aide but I didn't use much either.
 
I can't see the images unfortunately, but will the proper cotton improve the mids?  That is one thing I'm not liking right now, but I'll keep tweaking of course :)

 
In addition to BMF's response, you might also be able to go to Lowe's and pick up a pack of John Manville insulation for a bit over $3.00.  It is a small pack, and the insulation is 2" thick.  However, you can cut it to the size of the cups, then work with the layer thickness by removing some from the 2" standard thickness to see where yours tends to land in reference to the sound you desire.
 
Here is a link to the product to look for: http://www.jmhomeowner.com/products/product.asp?category=FiberGlass&Product=MultiPurposeRoll
 
Oct 15, 2012 at 2:08 AM Post #129 of 2,832
Thanks guys, I'll keep playing with it when I get some time.  We only have an Ace Hardware here and a dollar store, but I will grab a few things and see what sounds good, I just wanted to confirm that the damping had an effect on the mids :) 
 
Oct 16, 2012 at 4:00 PM Post #130 of 2,832
Many thanks go out to ktan3142 for letting us know Rite Aid Natural Absorbent Cotton is now available at the Rite Aid online store. Currently, it sells for $5.79 per box. This is the "good stuff."  Get it while it's available here.
 
Oct 17, 2012 at 3:47 AM Post #132 of 2,832
Quote:
BMF, which mod did you send to Tyll for measurements?

Ha! I was wondering when someone would ask this question.  I sent that set to Tyll in April, long before I developed the DBV series of mods.  DBV #2 and #3 have much more extended treble detail than what I sent Tyll. DBV #2 and #3 sound much better from top to bottom.
 
I will soon be posting a mod configuration for "Naked Drivers" that sounds as good and measures almost as well as DBV #2 and DBV #3.
 
Oct 18, 2012 at 1:07 PM Post #134 of 2,832
Might have missed it in the original post, but do you have measurements for DBV #3? This uses the square of magazine paper with felt on top (and nothing else), right? Really just curious to see how the magazine paper/felt damping behind the driver measure, including how adding holes to the felt change the sound.
 
Oct 18, 2012 at 7:16 PM Post #135 of 2,832
Quote:
Might have missed it in the original post, but do you have measurements for DBV #3? This uses the square of magazine paper with felt on top (and nothing else), right? Really just curious to see how the magazine paper/felt damping behind the driver measure, including how adding holes to the felt change the sound.

 
Thanks for your interest, hans.
 
Sorry, but I sent those headphones on to some friends out of state and out of the country. I made measurements of them but had the MacBook Pro "Pinwheel of Death." I had forgotten to save the files. When I "hard re-booted," I lost the REW data files.  I will have to build another one and make new measurements...on my "To Do List."
 
The magazine paper with stiff felt overlay is Added to DBV #2 which Includes Acoustipack Lite, Paxmate Plus "Ladder Rungs," fiberglass, and Rite Aid Natural Absorbent Cotton overlay in the cups, Newplast in the baffles and Shure 840 pads. All is described in the first post of this thread After Graph #55.
 

Users who are viewing this thread

Back
Top