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Fostex T50RP Incremental Mods and Measurements - Page 33

post #481 of 1215
Quote:
Originally Posted by Armaegis View Post

Has anyone here tried cutting holes into the under/inner-side of the pads similar to the Jerg mod for the HiFiMans?

 

Armaegis, why did Jerg cut holes in the under-side of the pads? What did he hope to achieve? 

post #482 of 1215

To reduce resonances and change frequency balance slightly. Lots of people seem to prefer his pads

 

Better decay and a slightly flatter response, with some mild shifting of ridges.

post #483 of 1215
Thread Starter 
Quote:
Originally Posted by Armaegis View Post

Well yes, I know there are some holes in the 840. Not that many though. Just wondering if anyone's cut them up some more. 

 

The various Beyer pads have them too in varying degrees. Or for some of the bigger/deeper pads with a definable inner wall, I wonder if cutting those out a bit would make a difference. There has been mention of lining those inner walls which has been beneficial to some degree; perhaps cutting out holes would accomplish a similar thing.

 

Ahh, O.K. I have some 840's begging for some more holes. I'll search Jerg's pad mod and give it a try. Let's compare notes.

post #484 of 1215
Quote:
Originally Posted by bluemonkeyflyer View Post

 

Ahh, O.K. I have some 840's begging for some more holes. I'll search Jerg's pad mod and give it a try. Let's compare notes.

BMF, I don't know if it will be truly worth much time to essentially "wreck" a pair of pads.  I know you mentioned you have a pair of 840s with "loose flaps" (er... lets keep that one out of the gutter).  If you're okay tearing those apart, then I suppose there'd be no love-loss.  The reason I don't think it'd be very effective in our Fostex setups is the nature of the 840 pads vs the Hifiman pads.  I believe the holes in pads are used as a pressure relief more than for sound enhancement.  Kinda like a blow-off valve for turbo'd cars.  Pads not having "vents", like say the one on Audeze's LCDx.x, create almost a suction on the head!  This ear-suction effect is a bit too intense and alters sound in my experience.  My reasoning why it was effective for Jerg is because of the specific setup between Hifiman cans and their pads.  See picture:

 

The ring that allows for attachment has holes.  Cutting into the pads like in a Jerg mod has an effect because waves can pass through the holes in the ring and through the holes in the pads and bounce around inside the pads.  I am not sure how effective this would be in a Tx0rp unless you were to stuff cotton (or similar material) in between the pads and the outter cups.  This would "lift" the pads off the cups to allow sound to enter into the inside of the pads through self cut holes.

 

This is just a theory, but I thought I would warn you about my predictions of the limitations.  (BTW, when I saw the Jerg post originally, I thought it made sense.  The more I looked at it, the more I didn't want to bother with all that work for little to no benefit in a Tx0rp configuration).

post #485 of 1215

Valid point. I think even a bit of fluffy material between the pad and baffle helps with some absorption though. 

 

I have a suspicion that the really thick pads with defined inner walls cause a lot of excessive ringing. 

post #486 of 1215
Thread Starter 
Quote:
Originally Posted by mrscotchguy View Post

BMF, I don't know if it will be truly worth much time to essentially "wreck" a pair of pads.  I know you mentioned you have a pair of 840s with "loose flaps" (er... lets keep that one out of the gutter).  If you're okay tearing those apart, then I suppose there'd be no love-loss.  The reason I don't think it'd be very effective in our Fostex setups is the nature of the 840 pads vs the Hifiman pads.  I believe the holes in pads are used as a pressure relief more than for sound enhancement.  Kinda like a blow-off valve for turbo'd cars.  Pads not having "vents", like say the one on Audeze's LCDx.x, create almost a suction on the head!  This ear-suction effect is a bit too intense and alters sound in my experience.  My reasoning why it was effective for Jerg is because of the specific setup between Hifiman cans and their pads.  See picture:

 

The ring that allows for attachment has holes.  Cutting into the pads like in a Jerg mod has an effect because waves can pass through the holes in the ring and through the holes in the pads and bounce around inside the pads.  I am not sure how effective this would be in a Tx0rp unless you were to stuff cotton (or similar material) in between the pads and the outter cups.  This would "lift" the pads off the cups to allow sound to enter into the inside of the pads through self cut holes.

 

This is just a theory, but I thought I would warn you about my predictions of the limitations.  (BTW, when I saw the Jerg post originally, I thought it made sense.  The more I looked at it, the more I didn't want to bother with all that work for little to no benefit in a Tx0rp configuration).

 

Reasonable theory, mrscotchguy. I'll need to let it percolate for a while.

Quote:
Originally Posted by Armaegis View Post

Valid point. I think even a bit of fluffy material between the pad and baffle helps with some absorption though. 

 

I have a suspicion that the really thick pads with defined inner walls cause a lot of excessive ringing. 

 

I'm on board. This effect is shown in the Pad Rolling graphs I posted last week. J$ and Alpha Pads have straight walls and saw-tooth FR in the upper register. Shure 840, Shure Velour, and Dog Pads are much better behaved...."Good Dog!"

 

Anyone interested, go to post 1 of this thread and scroll all the way down to the bottom.

post #487 of 1215

Did a variant of BMF v3 using HM5 pads while it was good I'm just not too thrill with bass not having enough oomph (the bass sound from a subwoofer) when compared to a vmoda m80 and TF10. Is this a result ortho tech or I am doing something wrong?

post #488 of 1215
Quote:
Originally Posted by snakeeater692 View Post

Did a variant of BMF v3 using HM5 pads while it was good I'm just not too thrill with bass not having enough oomph (the bass sound from a subwoofer) when compared to a vmoda m80 and TF10. Is this a result ortho tech or I am doing something wrong?

If you're following it the letter, then you're not doing enough. The point of the mod is to provide a guideline to produce something that resembles to what BMF is doing. After that, it's up to you how to adjust it to your taste. There's plenty of ways to get more bass out of the mod; BMF has written it in the first post too but the gist of it is to play around with the stiff felt behind the driver(s) and the vents. Get to it trooper!!
post #489 of 1215

BMF, I would like to think you for this thread. A buddy and I came across the T50RP modding hype relatively recently and in doing so, we ended up on this thread. I followed your DBV #3 tutorial and I am very impressed with the results. Based on your section for minor tweaking, I am confident that I can produce the sound I want with just a few added/removed tweaks. I would like to mention that I used all the materials recommended in the mod except the cotton/fiberglass. Putting six cotton balls in the cups made the cans almost too bright and after some fidgeting, I ended up with only two cotton balls. Instead of tearing them apart, I just placed them directly in the center of the cup, side by side, in order to have a fair amount of pressure on the stiffened felt. Even though the top and bottom third of the cup remains vacant, I am very impressed with the sound.

 

Anyway, keep up the awesome work!

post #490 of 1215
Thread Starter 
Quote:
Originally Posted by Thujone View Post

BMF, I would like to think you for this thread. A buddy and I came across the T50RP modding hype relatively recently and in doing so, we ended up on this thread. I followed your DBV #3 tutorial and I am very impressed with the results. Based on your section for minor tweaking, I am confident that I can produce the sound I want with just a few added/removed tweaks. I would like to mention that I used all the materials recommended in the mod except the cotton/fiberglass. Putting six cotton balls in the cups made the cans almost too bright and after some fidgeting, I ended up with only two cotton balls. Instead of tearing them apart, I just placed them directly in the center of the cup, side by side, in order to have a fair amount of pressure on the stiffened felt. Even though the top and bottom third of the cup remains vacant, I am very impressed with the sound.

 

Anyway, keep up the awesome work!

Kind of you to say so. Your pleasure and success is mine.  beerchug.gif 

 

As I've always said, the "initial build" is just the starting point. "Take anyone's mod and make it your own" by tuning, just as you have done.

 

...and, I am, so stay "tuned."  wink_face.gif  

post #491 of 1215

BMF,

 

Have you tried punching some 4 holes into the felt for the Naked Driver mod? I'm still doing some testing but the results thusfar are pretty good.

 

I got a pair of LCD-2s as well as another pair of T50RPs and 2 pairs of 840 pads. Should be a fun week.

 

I'm going to try to get my measurement setup working better and hopefully I will be able to get my T50RPs closer to LCD-2s.

 

Oh and my digital scale from ebay finally came in, so I should be able to provide detailed descriptions of my mods when(if) I reach some kind of sweet spot. 

post #492 of 1215
Thread Starter 
Quote:
Originally Posted by PhaedraCorruption View Post

BMF,

Have you tried punching some 4 holes into the felt for the Naked Driver mod? I'm still doing some testing but the results thusfar are pretty good.

I got a pair of LCD-2s as well as another pair of T50RPs and 2 pairs of 840 pads. Should be a fun week.

I'm going to try to get my measurement setup working better and hopefully I will be able to get my T50RPs closer to LCD-2s.

Oh and my digital scale from ebay finally came in, so I should be able to provide detailed descriptions of my mods when(if) I reach some kind of sweet spot. 

Hi PhaedraCorruption,

 

You Are Geared Up. Way to go and congrats on the LCD2's and 2 more sets of T50RPs!

No, I have not tried making holes in the stiffened craft felt when modding "Naked Drivers" (when the stock white driver damping material has been removed from the back of the drivers). Actually, I went the other way. Naked Drivers are too under-damped so bass is excessive, out of control, and so bloated it messes up the mids and covers up the treble frequencies. I posted the "Naked Driver" config, with graphs, that worked best for me in Post # 244 of this thread. I had to use two layers of stiffened craft felt without any holes to make the drivers behave. This mod configuration measures and performs very close to DBV #3. Here's the configuration: 

 

1. 2 layers of Michael's Craft Store stiffened craft felt, each measuring 45x52x1.5mm, notched for clearance of all 8 driver mounting screw heads, stacked, and secured with 3M Removable double-sided craft felt.

 

2. 20x25 rectangular thin card stock treble reflector centered over the back of the driver and secured under the stiffened craft felt with thin strips of 3M double-sided tape.

 

3. 1x7x7.5 cm compressed J&M fiberglass = 1.3 grams.

 

4. 1.5x7x7.5 cm Rite Aid Natural Absorbent Cotton = 1.4 grams, under the fiberglass. As a substitute, use "Prepared" layers of Rite Aid First Aid Rolled Cotton 2x7x7.5 cm = 1.8 grams OR 4 to 6 Rite Aid First Aid cotton balls as described near the bottom in Post #1 of this thread.

 

5. Acoustipack Lite (or Paxmate or Silverstone) 2x7 cm trimmed to fit the side cup floor "wells."

 

6. Newplast (or non-drying plasticine) flush loaded baffle compartments = 9 grams of Newplast.

 

7. Stock cup vent felt intact.

 

8. Stock Open baffle ports.

 

9. Shure 840 pads.

It's interesting that going the other way is working for you. Just goes to show "There are many paths leading to the same destination." beerchug.gif

Your measurement kit will be very helpful for dialing-in your mod config. I built an improved phantom power supply designed by solderdude. He posted his schematic at this link, if interested. Scroll down to Reply # 101. BTW, solderdude is an E.E. and designed the hybrid tube amps Jeremy builds and offers in kit form; they are impressive and inexpensive. You can also check out all the other cool DIY headphone related DIY projects solderdude designed and shared. Really quite an amazing body of work freely shared with the community!

Hope this helps.


Edited by bluemonkeyflyer - 5/1/13 at 5:47am
post #493 of 1215

I love my T50RPs! I thouroghly gave them effective damping mods and I am extremely happy with these sweet cans. I appreciate the spectrum analysis. This gives people a great insight as to what expect from a particular mod, or combinations you have painstakingly chronicled. Thanks a million BMF. 

post #494 of 1215

I've found my Bottlehead SEX 2.1 to drive these headphones amazingly well.  I am able to crank the volume to very high levels with no audible distortion.  The amount of detail and realism is fantastic but still very musical and smooth.  

post #495 of 1215
Quote:
Originally Posted by jgray91 View Post


If you're following it the letter, then you're not doing enough. The point of the mod is to provide a guideline to produce something that resembles to what BMF is doing. After that, it's up to you how to adjust it to your taste. There's plenty of ways to get more bass out of the mod; BMF has written it in the first post too but the gist of it is to play around with the stiff felt behind the driver(s) and the vents. Get to it trooper!!

 



I okay I finally got T50rp enough to my liking. Bass is good but could be better and could extend lower. Mine can not go lower than 27hz. Feel free to make any suggestion. Here's my tweaked BMFv3 so far:

 

1. Stiff craft with double sided type over stock white felt and driver

2. Plasticine Flush Mass Loaded in the baffle compartments (I did not weigh it) and also seal around the circumference

3. Silverstone foam both side of cups with rips, felt top and button of vents with black felt.

4. A piece gauge over foam and felt followed by a piece of 7mm Rock Wool with a hole directly where the vents with black felt is followed by 3 thin sheets of rolled rite aid cotton.

5. Scotch taped baffle port with a small needle hole on ear side.

6. HM5 with inner tube for pads.


Edited by snakeeater692 - 5/2/13 at 6:49pm
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