[jjswee]

First post here.  I am picking up a pair of T50's this week and because of my nature I have done hours of research before any purchase.
 
I've spent many hours in this thread alone after I finally started reading about the T50's.  No idea how I came to them, I think the Ortho thing intrigued me.  
 
BMF - I've actively followed your posts in here for many pages.  I think I started somewhere before your 6.2 and 6.3 days and ended around page 300.   I got tired of reading all the pages so I jumped to the end and saw you had a new version 8!  aaah!  And it is so different than 6.3!  I just read your google docs and its very interesting the big differences you made.   It brings me to some questions.
 
1) I see you are no longer mass loading the cups with dynamat?  Just using the acoustipack?   Also, those triangles you made, can you explain their benefit?  I have no idea how far back to read about them.
 
2) I feel there is a lot less use of clay/tungsten putty on the baffle?   Is this true?  You are just filling the compartments flush.  
 
3) No more material around the rim?  Is there no worry about sealing anymore?
 
4) You changed from transpore tape over the drivers to stock paper / felt / tape combo.  Is the tape making a big difference on the felt?  I remember you mentioning the extra tape limited the bass.  How does the felt under the tape change this?
 
5) Are you currently running with a close baffle port?
 
I think that is enough questions for now.  Haha.     I really appreciate all the work you have done with these headphones and how much you have shared.  You are truly a great addition to this community.  
 
Thanks,
 
Josh

 

[bluemonkeyflyer]

Quote:

First post here.  I am picking up a pair of T50's this week and because of my nature I have done hours of research before any purchase.
 
I've spent many hours in this thread alone after I finally started reading about the T50's.  No idea how I came to them, I think the Ortho thing intrigued me.  
 
BMF - I've actively followed your posts in here for many pages.  I think I started somewhere before your 6.2 and 6.3 days and ended around page 300.   I got tired of reading all the pages so I jumped to the end and saw you had a new version 8!  aaah!  And it is so different than 6.3!  I just read your google docs and its very interesting the big differences you made.   It brings me to some questions.
 
1) I see you are no longer mass loading the cups with dynamat?  Just using the acoustipack?   Also, those triangles you made, can you explain their benefit?  I have no idea how far back to read about them.
 
2) I feel there is a lot less use of clay/tungsten putty on the baffle?   Is this true?  You are just filling the compartments flush.  
 
3) No more material around the rim?  Is there no worry about sealing anymore?
 
4) You changed from transpore tape over the drivers to stock paper / felt / tape combo.  Is the tape making a big difference on the felt?  I remember you mentioning the extra tape limited the bass.  How does the felt under the tape change this?
 
5) Are you currently running with a close baffle port?
 
I think that is enough questions for now.  Haha.     I really appreciate all the work you have done with these headphones and how much you have shared.  You are truly a great addition to this community.  
 
Thanks,
 
Josh

 
Hi Josh,
 
Sounds like you've done your "homework."  I've shared my mods as they've developed and evolved over time. IMO, each generation has improved upon the previous ones. I leave it to each individual to try for themselves and draw their own conclusions. There are many materials and many methods that may arrive at the same SQ destination. Some may work for you that don't work for me, and vice versa. 
 
1. I found no sonic benefit to putting Dynamat inside the cups. I stopped using it inside in favor of putting it around the ear side of the drivers. According to Dynamat's web site, this is the best application for minimizing vibration-induced distortion.
 
"Paxmate Pyramids" is an innovation by Arleus. I used it in two mods with good results but I am not sure it adds significant SQ benefits to the configuration. I recommend that you read Arleus' excellent post from a month, or so, ago and give it a try. Arleus may have some comments about his results and recommendations.
 
2. I've tried the minimalist approach to "Super Mass Loading" the baffles with plasticine, homemade tungsten putty, and Newplast. I've found that, with my mods, "Flush Mass Loading" the baffles is the most effective method of mechanically dampening the baffles. Tungsten putty and Newplast perform similarly. Newplast is easier to use, less messy, and is easier to remove.
 
3. The seal around the cup-to-baffle rims is important. While tweaking, I apply masking tape around the rims to maintain a consistent seal from one mod cycle to the next. Tape also relieves some of the pressure on the cup threads if you squeeze the baffles to the cups as you apply the tape and firmly press it down. Once a mod is finished, I test the seal by tightening the screws as far as possible. If the threads have not been overly stressed, or stripped, I may not need to seal the rims. Squeeze the baffle to cup to test for "play." If the baffle moves at all, apply a bead of GE Silicone II around the rim and let it dry before mounting the pads.
 
4. I recommend leaving the stock white paper alone. Previous mods included a layer (or more) of Transpore directly over the driver paper. The adhesive from the Transpore may interact with the adhesive and/or paper so that, over time, the driver paper may loosen. Stiffened craft felt or wool felt applied directly over the white driver paper is a better approach, IMO. I may apply a square of Transpore over the stiffened craft felt if I need to further dampen the driver. Alternatively, you could install an additional square of stiffened felt over the first layer. The second layer may need to be the same size as the first, or smaller, depending on how much additional dampening is needed for the mod you're working on.
 
5. I either keep the stock baffle port intact or modify depending on whether I need more or less bass. Follow my Google Doc for one approach to modifying the stock baffle port. A smaller baffle port yields more bass. My current mods use either a fully open stock baffle port or a modified baffle port down to a minimum opening of 1 mm. The stock baffle port is approximately 3 mm in diameter.
 
Thank you for your kind words.
 
Good luck with your mods.

 

[sling5s]

Hi bluemonkeyflyer, thanks for all your continued sharing of innovations and improvements.
I used to have 2 vents closed and than 3 closed and now just closed all 4 vents.  It produces less bass but to me it's tighter and more controlled.
Would closing all vents produce what you describe as pressure equalization problem?
And if you could you elaborate what you mean by pressure equalization problems?
 
many thanks
Quote:

 Make it too small and you may have pressure equalization problems.

 

[jjswee]

Thanks for the reply!     What is the purpose of the tape around the edge?  I am still confused about that.
 
I happen to have some shopping list problems as some items can't be bought in the US.  It seems I can not buy Newplast.  Should I get plasticine (150g for 10 bucks) or try my hand with tungsten putty (available many places)?
 
As for the dynamat - I will be buying a different product from 'Second Skin Audio'.  They are a company I have dealt with before and I've spoken with the starter of the company (seems he is no longer the owner?) and feel its a better product.  Here is a link.  http://secondskinaudio.com/index.php/products/vibration-dampers-cld/damplifier2012-04-04-17-34-47-detail    I'll be happy to send you some to compare.   They have a regular version that is .35lb/sqft at 1 mm thickness and a pro version that is .6lb/sqft at 2mm thickness.  Comparing this to Dynamat extreme which is .45lb/sqft at 1.7mm thickness.   
 
Josh

 

[bluemonkeyflyer]

Quote:

Hi bluemonkeyflyer, thanks for all your continued sharing of innovations and improvements.
I used to have 2 vents closed and than 3 closed and now just closed all 4 vents.  It produces less bass but to me it's tighter and more controlled.
Would closing all vents produce what you describe as pressure equalization problem?
And if you could you elaborate what you mean by pressure equalization problems?
 
many thanks

 
Hypothesis (aka, A wild guess!):  There is "X" amount of air inside the cups as well as inside the ear pads-to-head spaces. If the cups are completely sealed and you have a complete seal (not likely due to hair, etc.) of ear pads to your head, there is theoretically no way for the pressure to equalize with the outside ambient pressure. Movement of the driver diaphragm pressurizes air in the cup and ear pad spaces because it is bipolar. Providing a means for some pressure relief of both spaces is needed for making the headphones reasonably efficient and consistent in SQ with changes in barometric pressure.  This is nothing more than conjecture on my part. Nevod and others "more in the know" may wish to elaborate or correct my misconceptions. Bottom line: In my experience, maintaining a tiny bass port and some degree of a baffle port sounds better, to me, because the bass is "tamed" but still present when the recording calls for it.
 
Quote:

Thanks for the reply!     What is the purpose of the tape around the edge?  I am still confused about that.
 
I happen to have some shopping list problems as some items can't be bought in the US.  It seems I can not buy Newplast.  Should I get plasticine (150g for 10 bucks) or try my hand with tungsten putty (available many places)?
 
As for the dynamat - I will be buying a different product from 'Second Skin Audio'.  They are a company I have dealt with before and I've spoken with the starter of the company (seems he is no longer the owner?) and feel its a better product.  Here is a link.  http://secondskinaudio.com/index.php/products/vibration-dampers-cld/damplifier2012-04-04-17-34-47-detail    I'll be happy to send you some to compare.   They have a regular version that is .35lb/sqft at 1 mm thickness and a pro version that is .6lb/sqft at 2mm thickness.  Comparing this to Dynamat extreme which is .45lb/sqft at 1.7mm thickness.   
 
Josh

 
Are you referring to the masking tape?  If so, I use it to make sure there is no more pressure leakage than I want And to make sure this variable is controlled when I am testing the effects of another single mod.  When your headphones are "fresh," the screws will tighten down to fully seat the baffle to the cup. The driver will seat solidly onto the 4 rubber shock absorbers. There will be no leakage from the rims. After multiple mod cycles, however, the cup threads wear down and you will find the baffle will not completely seal with the cups. You can test this by simply squeezing the cups/baffles with your fingers. If there is any movement of the baffle, or "springiness," you will lose more pressure than you intend from your modified bass port and your modified baffle port. Masking tape will correct this problem if you apply it all the way around the rims and press it down firmly in all the crevices. Once you've finished with your tweaks, you can make two additional mods to duplicate the effects of the masking tape used for temporarily sealing the rims:
 
1. Use super glue to fill the cup thread chambers. Use a paperclip to "tamp" the glue all the way down into the chambers. Let it dry for 24 hours. Use a 1/16" drill bit and drill slowly to the depth of the baffle-to-cup screw threads. Make sure you drill perpendicularly. Next, mount your baffle onto the cup and slowly tighten the screws. This will tap new threads in the super glue. I find these new threads are "good" for 30 or 40 modding cycles.
 
2. Use GE Silicone II around the baffle-to-cup rims. Wear disposable latex glove and smooth the silicone with your finger. Let it dry. Now you have a good seal around the rim. It easily comes off in a single strand if you ever want to change something on the inside.
 
In addition, If your headband hanger outer clasp (Connector B) threads are stripped, go to this link and see post # 5372:
 
http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/5370
 
Here's the link for the exploded view of the headphones, post # 1858:
 
http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/1845#post_7610095
 
Yes, I would like to try a sample of your Dynamat substitute, Thank You!  I can also send you some Newplast. Please PM me. Tungsten putty is labor-intensive to make, no better than Newplast, and costs more to make than you can buy Newplast from Chroma Colour in England, even with the exorbitant shipping charges.

 

[juustinb]

Too long have I considered this $75 purchase.  About to buy a pair right now.

 

[sling5s]

But aren't closed headphones without bass porting where air can flow and therefore without pressure relief?
 
Quote:

 
Hypothesis (aka, A wild guess!):  There is "X" amount of air inside the cups as well as inside the ear pads-to-head spaces. If the cups are completely sealed and you have a complete seal (not likely due to hair, etc.) of ear pads to your head, there is theoretically no way for the pressure to equalize with the outside ambient pressure. Movement of the driver diaphragm pressurizes air in the cup and ear pad spaces because it is bipolar. Providing a means for some pressure relief of both spaces is needed for making the headphones reasonably efficient and consistent in SQ with changes in barometric pressure.  This is nothing more than conjecture on my part. Nevod and others "more in the know" may wish to elaborate or correct my misconceptions. Bottom line: In my experience, maintaining a tiny bass port and some degree of a baffle port sounds better, to me, because the bass is "tamed" but still present when the recording calls for it.

 

[bluemonkeyflyer]

Quote:

But aren't closed headphones without bass porting where air can flow and therefore without pressure relief?
 

You got me! LOL.  I don't know if my hypothesis is "sound" or if it's all wet. Whatever the mechanisms involved, my mods that include a modified bass port and a modified baffle port sound better than without. YMMV. Try it both ways and decide what sounds best to you.

 

[sling5s]

thank you.  I have not looked up the modfied bass port but i'll try opening up maybe a 1 or 2mm.  
really appreciate all your help.
Quote:

You got me! LOL.  I don't know if my hypothesis is "sound" or if it's all wet. Whatever the mechanisms involved, my mods that include a modified bass port and a modified baffle port sound better than without. YMMV. Try it both ways and decide what sounds best to you.

 

[bluemonkeyflyer]

thank you.  I have not looked up the modfied bass port but i'll try opening up maybe a 1 or 2mm.  
really appreciate all your help.

Your pleasure is mine.

Best wishes.

 

[Congo5]

Quote:

You got me! LOL.  I don't know if my hypothesis is "sound" or if it's all wet. Whatever the mechanisms involved, my mods that include a modified bass port and a modified baffle port sound better than without. YMMV. Try it both ways and decide what sounds best to you.

If we had a completely sealed cup.
And the baffle port is not clogged...the pressure would be equal on both sides of driver...
 
so I can not think of any reason the driver would care..
even if we were in a pressure tank or at high altitude.
In a vacuum yes because these things are air dampened.
gravitational forces do also matter. (Was going to include "on the moon")
 
In SCUBA the pressure does not noticeably affect hearing. Isn't the ear drum like a driver?
 
as always sometimes i am completely wrong......

 

[rhythmdevils]

The conventional wisdom in the ortho thread is that if you have a completely closed cup behind the driver, it physically prevents the driver from moving properly.  You can visualize it simply by picturing the driver needing to "push air" forward and backward, and a sealed chamber prevents this by keeping the driver from moving as far backwards because it's pushing against the air pressure, thus cutting off bass response.  However, a sealed cup with a baffle vent woudln't have that effect.  IME the cup venting requirements vary with your damping scheme.  And all laws of orthodome are made to be broken. 

 

[khbaur330162]

I showed these pictures to a friend and he thought it'd be nice if I posted them in here. I know this goes against most of what people are saying, but I did it, bass is not lost, and apart from what I feel are inherent drawbacks with the enclosure/driver (they're not exactly my cup of tea) it sounds perfectly fine.
 
Sacrilege:
 





 
List of mods:
Grill modded/felt in front of drivers removed
Dynamat on front of baffles
Plasticine damped baffles and around baffle lip
Removed damping glued over rear vents
Opened rear vents (the faux vents above the ball joint)
Added vents
Sealed baffle port tube
Holes punctured in rear driver paper, chamois damping added after realizing the mistake
Angled, hand stitched micro fiber pads with felt dust cover sewn in (since the photo's I've Kramer modded them with Nickel sized holes)
Headband pad added (felt + foam cushion to make it fit my head)
 
Random note, those vinyl pads that you can see in the third picture are AKG K240 pads. Good fit, not so good sound, imo.
 
Cheers, guys.

 

[Nevod]

Quote:

If we had a completely sealed cup.
And the baffle port is not clogged...the pressure would be equal on both sides of driver...
 
so I can not think of any reason the driver would care..
even if we were in a pressure tank or at high altitude.
In a vacuum yes because these things are air dampened.
gravitational forces do also matter. (Was going to include "on the moon")
 
In SCUBA the pressure does not noticeably affect hearing. Isn't the ear drum like a driver?
 
as always sometimes i am completely wrong......

If baffle port is there, no problem then. Though IIRC all closed cans have baffle port in some way - at least in form of leaks, there's no really sealed stock can.
Ear is not sealed, it is connected to pharynx via Eustachian (sp?) tube exactly for pressure equalisation purposes. SCUBA provides air at ambient water pressure, so ear is pressure-equalised. If you dive over 3m without any gear,  pressure gets noticeable and you have to blow the tube by 'pushing' air into them.

 

[nick n]

Quote:

I showed these pictures to a friend and he thought it'd be nice if I posted them in here. I know this goes against most of what people are saying, but I did it, bass is not lost, and apart from what I feel are inherent drawbacks with the enclosure/driver (they're not exactly my cup of tea) it sounds perfectly fine.
 
Sacrilege

SACRILEGE?
no way I think that's very interesting, and i might just go and attempt a similar thing, but with mesh rears. Why not, there's more Fostex headphones be had and nothing ventured nothing gained. Not like they are rare or anything.
 
Also interesting to see that you say there's no lost bass. Any ideas or hunch if that's because of puncturing the rear stock damping?  Do you find the resonant aspect lower or gone even now?
 
Don't forget about that white driver rear fabric you got in case you feel like replacing it.
 
Thanks for that post and pictures. Have a feeling this is going to put a pair of mine under the dremel. Who knows when though ( added to pile of projects )