Latest Thread Images

Featured Sponsor Listings

Fostex T50RP Incremental Mods and Measurements

Nov 16, 2012 at 9:05 AM Post #181 of 2,874
I have just understood that perhaps my somewhat uneven freq. responce might be caused by the fact I've removed front black felt from baffle and, hence, driver and I don't have it anymore.
BMF, do you have knowledge on how does removal of black felt affects driver's damping and is it possible to compensate for the lack of it?
 
Nov 16, 2012 at 9:34 AM Post #182 of 2,874
Quote:
nevod said:
I have just understood that perhaps my somewhat uneven freq. responce might be caused by the fact I've removed front black felt from baffle and, hence, driver and I don't have it anymore.
BMF, do you have knowledge on how does removal of black felt affects driver's damping and is it possible to compensate for the lack of it?
Click to expand...

Some people have reported improved treble after removing the ear side dust cover. Personally, I cannot tell a difference one way or the other so I keep in place simply to keep debris and dust from entering the driver. Look at Picture "S" near the bottom of Post #1 in this thread. The dust cover is "sandwiched" between two, 1.5mm pieces of stiff craft felt to show just how thin and porous it is. 
 
Organdi "cloth" is a very thin, loosely woven single ply material. It may serve as an approximate replacement for the stock dust cover's acoustic properties (if any) and it will prevent dust and debris from potentially fouling the driver. You may be able to find Organdi in fabric stores or on eBay. If you cannot locate any, PM your address I can will send you some to try.
 
I assume the "uneven freq. response" you mention is tilted towards the treble range. If so, you can try thin pieces of cotton, fiberglass, thin felt, various layers of first aid gauze, or similar materials over the ear side of the driver. I've used all these materials to tune down treble peaks. J&M fiberglass over the driver with one or two layers of gauze between the fiberglass and the undersurface of the ear pad dust cover works well, is easily separated for fine-tuning its thickness:treble reduction factor, does not penetrate the Shure 840 pads, and I've experienced no irritation using it this way. Some people are more sensitive to me and/or are concerned about health risks; I'm not concerned about using fiberglass if it is contained inside the cups and under ear pad dust covers.
 
Nov 16, 2012 at 11:47 AM Post #183 of 2,874
Organdi is more similar to the driver dust cover that is under the black felt, the black cloth is relatively dense IIRC. If it doesn't make serious difference, then no problem, besides seems I do have material that is somewhat similar, though it's less dense and thicker.

The unevenness I'm talking about is below 6 kHz range, I do know that after that frequency, reflections start to play a big role and I do cover entire earside with acoustic foam - even over the driver, excluding places right over holes in magnet plates. The driver coverage is less than ideal, perhaps 60% of the whole potentially reflective area, but there are anyways no large uncovered areas. I also have internal surfaces of earpads (I use beyer gels) covered with acoustic foam.
It has indeed helped the high frequency region both by measurement and by ear - more detail and at once less harsh and fatiguing.

Though I do have less than ideal attachment of damper to the driver, and I have an idea how to fix it recently. I don't really haste to mod my phones, so can't say when I'll implement it - it's already pleasant for ears, so there's not so much motivation.
My current mod is not exactly DBV, but has some similarities. I have cups fully coated in acoustic foam (really absolutely completely, sides too), baffle with dynamat + described foam coat on earside and dynamat in compartments on internal side, covered with foam. Interior is filled with polyfill.
The damper consists of 4 layers of a material that is similar in consistency to the black felt, but a bit looser and thicker, they are bonded together by electrician tape on the perimeter (error 1) and it is attached to the driver by a plasticine ring (error 2). So it's loose internally with air gaps between layers and leaks air through plasticine ring. I plan to glue layers together on the sides, use plasticine over damper instead of under it and also add some stuff to keep it pressed against driver so there would be no air gaps.

Also there's a square of electrician tape on driver side of the damper and a square piece of luffa sponge on the cup side. 9 needle holes are punched through the tape and damper over driver's center square.

It sounds pleasant to me ( but I haven't ever heard anything good) but it's nowhere as perfect on measurements of the DBVs. I do have some plans on it but I'm in no rush. In a few weeks I'll certainly do some work on them.

By the way, BMF, how do you do your measurements? Do you insert the mic into ear canal entrance or do you use some flat baffle, or a dummy head? I insert the mic into canal ear, not so much into canal as mine isn't WM61, but an EM 9767, which is significantly larger. It's also somewhat less linear.
 
Nov 16, 2012 at 12:11 PM Post #184 of 2,874
Quote:
nevod said:
Organdi is more similar to the driver dust cover that is under the black felt, the black cloth is relatively dense IIRC. If it doesn't make serious difference, then no problem, besides seems I do have material that is somewhat similar, though it's less dense and thicker.
The unevenness I'm talking about is below 6 kHz range, I do know that after that frequency, reflections start to play a big role and I do cover entire earside with acoustic foam - even over the driver, excluding places right over holes in magnet plates. The driver coverage is less than ideal, perhaps 60% of the whole potentially reflective area, but there are anyways no large uncovered areas. I also have internal surfaces of earpads (I use beyer gels) covered with acoustic foam.
It has indeed helped the high frequency region both by measurement and by ear - more detail and at once less harsh and fatiguing.
Though I do have less than ideal attachment of damper to the driver, and I have an idea how to fix it recently. I don't really haste to mod my phones, so can't say when I'll implement it - it's already pleasant for ears, so there's not so much motivation.
My current mod is not exactly DBV, but has some similarities. I have cups fully coated in acoustic foam (really absolutely completely, sides too), baffle with dynamat + described foam coat on earside and dynamat in compartments on internal side, covered with foam. Interior is filled with polyfill.
The damper consists of 4 layers of a material that is similar in consistency to the black felt, but a bit looser and thicker, they are bonded together by electrician tape on the perimeter (error 1) and it is attached to the driver by a plasticine ring (error 2). So it's loose internally with air gaps between layers and leaks air through plasticine ring. I plan to glue layers together on the sides, use plasticine over damper instead of under it and also add some stuff to keep it pressed against driver so there would be no air gaps.
Also there's a square of electrician tape on driver side of the damper and a square piece of luffa sponge on the cup side. 9 needle holes are punched through the tape and damper over driver's center square.
It sounds pleasant to me ( but I haven't ever heard anything good) but it's nowhere as perfect on measurements of the DBVs. I do have some plans on it but I'm in no rush. In a few weeks I'll certainly do some work on them.
By the way, BMF, how do you do your measurements? Do you insert the mic into ear canal entrance or do you use some flat baffle, or a dummy head? I insert the mic into canal ear, not so much into canal as mine isn't WM61, but an EM 9767, which is significantly larger. It's also somewhat less linear.
Click to expand...

 
No, the black material over the ear side of the baffle and driver is ultra thin and porous, no more than 0.2 mm thick. It reminds me of inexpensive 1-ply toilet paper.  Look at photo "S" in the first post of this thread to see just how thin and porous it is. The Organdi I have is similar to the stock dust cover thickness. I have another material a Canadian friend sent me that's even better; I think it is speaker cloth.
 
The black felt over the inside of the cup vents is stiffened felt and it's ~ 1 mm thick.
 
The only dummy head I use is the one between my ears!  
darthsmile.gif
 I stick the mic in my ear canal using Etymotic triflange ear tips.
 
Nov 16, 2012 at 1:39 PM Post #185 of 2,874
I've managed to track down everything I need to start modding, except cotton and acoustipak and paxamate/silverstone.

I ordered that cotton off Ebay, it looks pretty promising.

http://www.ebay.com/itm/First-Aid-Sterile-Absorbent-Cotton-Roll-5-oz-01-kg-/261017451390?pt=LH_DefaultDomain_0&hash=item3cc5da3b7e

I will give some comments and post some pictures of it when it shows up.

Can anyone hook me up with some acoustipak and paxamate/silverstone? That would be awesome. I can pay shipping :)

*edit* 

Whoops, meant to post that in the big thread already full of posts like this, my bad
 
Nov 16, 2012 at 2:48 PM Post #186 of 2,874
Quote:
chrislangley4253 said:
I've managed to track down everything I need to start modding, except cotton and acoustipak and paxamate/silverstone.

I ordered that cotton off Ebay, it looks pretty promising.

http://www.ebay.com/itm/First-Aid-Sterile-Absorbent-Cotton-Roll-5-oz-01-kg-/261017451390?pt=LH_DefaultDomain_0&hash=item3cc5da3b7e

I will give some comments and post some pictures of it when it shows up.

Can anyone hook me up with some acoustipak and paxamate/silverstone? That would be awesome. I can pay shipping :)
Click to expand...

 
P.M. me.
 
Nov 19, 2012 at 12:33 AM Post #187 of 2,874
Hello,
I got a set of T-50's in May and started mod's with what I had around the house,
and from the craft store. Then ordered Silverstone from Amazon, by July I was very
happy, I tuned them against Stax SR-5N and they became my faviorite phones.
Until one day when I got my hands on real BMF [size=9pt]DBV #3.[/size]
[size=9pt]mine were good these were better, clearly better.[/size]
[size=9pt]BMF's mod's are so simple, yet work so well.[/size]

 
So it was time to make some changes

yesterday's mod cycles:

added paxmate logs, exchanged some cotton for fiberglass and started taping the baffle to cup.
not much difference.

sealed baffle holes, added 22mm paper disc, removed transpore tape from driver felt.
Huge difference.

removed tape sealing cup vents ... for more bass.

  They were close before but some things used were there to make up for the missing pieces of the config.
He had suggested the magazine paper but I thought ( I don't need more treble)
Could not have been more wrong.
 It does many helpful things.
It helps control driver movement...helps bass.
I have no idea why it helps mids but it does.
I think it reflects a frequency that helps with imaging.
and more...........

 
I would need better phones to tune against in order to determine any direction I might want to go towards.

These changes add up to a large improvement..

 

  I stayed up late A/B-ing with BMF [size=9pt]DBV #3[/size] and am happy. used different amps/ settings- all computer driven..
If your shure 840 pads get stretched out like mine did try using rubber cement on the fabric.
  I soak the pad flaps in rubber cement... on the fabric side.
it stiffens them up and helps with the seal and so they don't slip off...
the glue wipes right off of cups so is not messy....
Thanks to everyone who posts here.
To BMF:You have done great service to the community with your work ..
Thank You
 
Nov 19, 2012 at 12:53 AM Post #188 of 2,874
Awesome post Congo! I wish all new guys (and a lot of the old guys too) posted so concisely. Also, good tip with the rubber cement. I bet contact glue would work great, for a permanent seal. That stuff rubs off just like the rubber cement before it sets.. but, once it sets it's pretty much stuck :)
 
Nov 19, 2012 at 8:46 AM Post #189 of 2,874
Quote:
congo5 said:
Hello,
I got a set of T-50's in May and started mod's with what I had around the house,
and from the craft store. Then ordered Silverstone from Amazon, by July I was very
happy, I tuned them against Stax SR-5N and they became my faviorite phones.
Until one day when I got my hands on real BMF [size=9pt]DBV #3.[/size]
[size=9pt]mine were good these were better, clearly better.[/size]
[size=9pt]BMF's mod's are so simple, yet work so well.[/size]

 
So it was time to make some changes

yesterday's mod cycles:

added paxmate logs, exchanged some cotton for fiberglass and started taping the baffle to cup.
not much difference.

sealed baffle holes, added 22mm paper disc, removed transpore tape from driver felt.
Huge difference.

removed tape sealing cup vents ... for more bass.

  They were close before but some things used were there to make up for the missing pieces of the config.
He had suggested the magazine paper but I thought ( I don't need more treble)
Could not have been more wrong.
 It does many helpful things.
It helps control driver movement...helps bass.
I have no idea why it helps mids but it does.
I think it reflects a frequency that helps with imaging.
and more...........

 
I would need better phones to tune against in order to determine any direction I might want to go towards.

These changes add up to a large improvement..

 

  I stayed up late A/B-ing with BMF [size=9pt]DBV #3[/size] and am happy. used different amps/ settings- all computer driven..
If your shure 840 pads get stretched out like mine did try using rubber cement on the fabric.
  I soak the pad flaps in rubber cement... on the fabric side.
it stiffens them up and helps with the seal and so they don't slip off...
the glue wipes right off of cups so is not messy....
Thanks to everyone who posts here.
To BMF:You have done great service to the community with your work ..
Thank You
Click to expand...

 
Congo5,
 
Congrats on your implementation of a mod configuration that you like! I really like your idea of using rubber cement on stretched pad flaps and will be giving this a try.
 
Did you use the phantom power supply and Panasonic mic in your ear or your Radio Shack SPL meter?  How do you capture the test sweep when using the SPL meter? I was never able to make it work consistently.
Thanks for taking the time to post your results, impressions, and feedback.  
beerchug.gif

 
Nov 19, 2012 at 10:03 AM Post #190 of 2,874
Quote:
bluemonkeyflyer said:
 
Congo5,
 
Congrats on your implementation of a mod configuration that you like! I really like your idea of using rubber cement on stretched pad flaps and will be giving this a try.
 
Did you use the phantom power supply and Panasonic mic in your ear or your Radio Shack SPL meter?  How do you capture the test sweep when using the SPL meter? I was never able to make it work consistently.
Thanks for taking the time to post your results, impressions, and feedback.  
beerchug.gif
Click to expand...

 

 I know its not supposed to be accurate above 2k but.... it has been consistent and agrees with my ears...

Creative X-fi SB1090  line in.  This works for me, it might be  how I seal it to the
phones with felt, cardboard and a foam spacer or ??
 
  The panasonic mic did not differentiate what was obvious, may try again,it should have worked..
 
Nov 20, 2012 at 9:09 AM Post #191 of 2,874
"Magic" Bass and Treble Tuners
 
Bass
 
1. Buy a hole punch. I bought an "i-punch" from Michael's for ~ $15.00. It has 6 hole punches with diameters ranging from 2.5 mm to 6 mm.
 
2. Start with 2.5 mm holes in the 40x40 mm stiff felt overlaying the 4 corner driver grids. This produces noticeably greater bass quantity/impact without bass bloat.
 
3. For even more bass, either punch holes in the felt overlaying more of the drivers' grid spaces OR punch larger holes. Go too far and you'll begin to hear bass bloat.
 
 
Treble
 
1. Use glossy magazine paper, thin card stock, or Transpore tape. I'm not certain but Transpore seems to produce a bit warmer quality than paper. Start with a Disk the size of a U.S. dime coin. You can actually use the dime as your template by placing on a piece of paper the size of a nickel or quarter U.S. coin and use scissors to trim around the coin.
 
EDIT: After many A/B comparisons, I am confident that with my ears/audio chain Transpore (27 mm wide X 40 mm long oriented North-South) produces a slightly "warmer" sound compared to paper treble reflectors that produce a slightly "crisper" sound.
 
2. Place the Disk on the center of the back of the driver grid with double sided tape or use Congo5's method with rubber cement to hold the Disk on the center of the 40x40 mm stiff felt, then center the stiff felt onto the driver with the paper Disk "face down."
 
3. For more treble, cut out a paper Disk the size of a nickel. For even more, make your disk the size of a quarter (coin). 
 
4. Alternately, cut a strip of Transpore tape from a roll 3/4" wide (27 mm) and 40 mm long. Place the tape on the stiff felt, centered so there is equal un-taped area on either side. Place the stiff felt onto the driver with the Transpore "face down" and secured with double sided tape all the way around the driver perimeter. Make sure your double sided tape does not overlay any of the driver grids or you will inadvertently increase the "damping factor" on that side which will create a Left-Right imbalance. Also, let's agree that the side of the driver nearest the solder pads is "South." Place the stiff felt/Transpore in a "North-South" orientation for More treble reflection or "East-West" for slightly less treble reflection...count the holes in the driver grid.
 
I have repeated these steps on multiple sets of T50RPs and other sets, including vintage orthos, and they work "as advertised" every time, for me...YMMV. Tuning Bass and Treble with these methods is linear. I believe they work independently. This means that if, for example, you're happy with the treble but want more bass you can leave the treble reflector (or lack, thereof) "as is" and punch holes in the stiff felt. The treble remains unaffected but you gain more bass. Alternatively, say you are happy with the bass FR but want a little more sparkle and treble details, change the size of the treble reflector and leave the felt alone.
 
Note that the FR may suffer if you "go too far" with the number/size of holes in the flet and too large with the paper size or Transpore "coverage."
 
 
Other tweaks:
 
1. Add cotton and/or fiberglass by 5 mm increments (thickness) for less bass and more treble.
 
2. Remove cotton and/or fiberglass by 5 mm increments (thickness) for more bass and less treble.
 
3. Make a modified bass port to further tighten and reduce bass quantity by covering all the cup vents except 3 to 6 mm of one of the four slots. Try this on the outside of the vents, first.
 
4. Seal the ear side baffle ports for a bit more bass and a bit more lower treble.
 
5. Apply cotton, fiberglass, or felt over the ear side of the driver and under the Shure 840 pads' dust covers to tame bright treble and sibilance, if present.
 
6. DBV #3 mods (and variations) were developed with Shure 840 pads. See the measurement graphs comparing stock pads and FA-003 pads with 840's. Other pads may work.
 
7. Stuffing material under the pads to elevate them may improve sound stage but at the expense of bass.
 
 
I would appreciate hearing from anyone who tries these methods. Please post your results and impressions.
 
Nov 20, 2012 at 9:40 AM Post #192 of 2,874
Quote:
congo5 said:
Hello,
I got a set of T-50's in May and started mod's with what I had around the house,
and from the craft store. Then ordered Silverstone from Amazon, by July I was very
happy, I tuned them against Stax SR-5N and they became my faviorite phones.
Until one day when I got my hands on real BMF [size=9pt]DBV #3.[/size]
[size=9pt]mine were good these were better, clearly better.[/size]
[size=9pt]BMF's mod's are so simple, yet work so well.[/size]

 
So it was time to make some changes

yesterday's mod cycles:

added paxmate logs, exchanged some cotton for fiberglass and started taping the baffle to cup.
not much difference.

sealed baffle holes, added 22mm paper disc, removed transpore tape from driver felt.
Huge difference.

removed tape sealing cup vents ... for more bass.

  They were close before but some things used were there to make up for the missing pieces of the config.
He had suggested the magazine paper but I thought ( I don't need more treble)
Could not have been more wrong.
 It does many helpful things.
It helps control driver movement...helps bass.
I have no idea why it helps mids but it does.
I think it reflects a frequency that helps with imaging.
and more...........

 
I would need better phones to tune against in order to determine any direction I might want to go towards.

These changes add up to a large improvement..

 

  I stayed up late A/B-ing with BMF [size=9pt]DBV #3[/size] and am happy. used different amps/ settings- all computer driven..
If your shure 840 pads get stretched out like mine did try using rubber cement on the fabric.
  I soak the pad flaps in rubber cement... on the fabric side.
it stiffens them up and helps with the seal and so they don't slip off...
the glue wipes right off of cups so is not messy....
Thanks to everyone who posts here.
To BMF:You have done great service to the community with your work ..
Thank You
Click to expand...

How does one go about trying a "real" BMF DBV #3 ?
 
Nov 20, 2012 at 10:07 AM Post #193 of 2,874
Quote:
onefatsurfer said:
How does one go about trying a "real" BMF DBV #3?
Click to expand...

Name your first child "BMF", read the entire Incremental Mods and Measurements thread and pass an aural exam, and be a member "in good standing" of The International DIY Headphone Modification Association.
 
Pay shipping to/from you, keep for a week and then return them to me, and you only pay if the headphones are damaged or lost. While you have them, feel free to open them up to peak inside. PM me.
 
Nov 20, 2012 at 10:50 AM Post #194 of 2,874
Great job BMF. Appreciate your endeavours and readiness to let others participate and learn. The incremental mod thread is evidence of your incredible commitment to the DIY spirit and belief in sharing. Chapeau!
Now, what about sending a pair to purrin and having them measured to find out how they fare against LFF's Paradox? 
 
Nov 20, 2012 at 11:08 AM Post #195 of 2,874
Whoa! I've received a lot of emails asking about the cost of my modded headphones. To be more clear and to avoid any further confusion, I'm not competing with Members of the Trade and I'm not selling modded headphones. Instead, I share everything that works and sounds good to me for others to try or ignore. I always encourage people to DIY, try a mod, and tune it "to make it  your own."
 
Best to All
 
You must log in or register to reply here.

Users who are viewing this thread

Total: 6 (members: 0, guests: 6)
Back
Top