Fostex T50RP Incremental Mods and Measurements
Nov 4, 2012 at 4:34 PM Post #166 of 2,832
Yes, I've tried open cell foam just like the one in the link. I could never find a configuration with it by itself and in combination with other materials that works as well as DBV #3.


I see. Thanks!
 
Nov 4, 2012 at 11:01 PM Post #167 of 2,832
I see. Thanks!


Of course, I did not mean to imply that you or others can't succeed with open cell foam where I failed.

There are many paths to the same destination. For example, I'm listening to a DBV #3 with No cotton. Instead, I used a full 2-inch block of J&M Fiberglas notched and trimmed in the usual fashion. Compressed with my hand and then released, it measures ~ 3 cm thick and 6.5x7.0 cm W/H and weighs 3 grams. All the other DBV#3 components are the same as described in the OP after Graph 55. The sound is real good but a bit bassy for me, yet without bloat.

A different path is DBV #3 substituting 15x70x75 mm rock wool sandwiched between gauze in place of cotton + fiberglass. Gauze keeps it all together. Place it in the cups after trimming to fit the cups and around the jack in the left cup, then firmly compress it into the cup floor. Punch 3 mm holes in the stiff craft felt over the 4 corner driver grids if you need more bass. This configuration also sounds good after tuning.

Some people may be sensitive to fiberglass or afraid to use fiberglass and rock wool. If so, use cheap disposable gloves and paper air filters sold at Lowes where you also get J&M fiberglass. Cover your work surface with a cloth or paper. Neither one will get out once the cups are closed Unless you remove the cup vent felt (Don't), remove the stock white dampener (NO, Stop...Don't do it!), and fail to seal the jack.

I always gravitate back to DBV#3 as described with cotton + fiberglass overlay which sounds the best to my ears with my audio chain. As always, YMMV.
 
Nov 6, 2012 at 4:49 PM Post #168 of 2,832
Quick question, when newplast is applied to the back of the baffle does this close off the baffle port.  If so, should the baffle port be opened from the ear side with something like a paper clip or a sewing needle.  Thanks.
 
Phill
 
Nov 6, 2012 at 4:58 PM Post #169 of 2,832
Quote:
Quick question, when newplast is applied to the back of the baffle does this close off the baffle port.  If so, should the baffle port be opened from the ear side with something like a paper clip or a sewing needle.  Thanks.
 
Phill

Phill,
 
The baffle port is the hole at the outside corner - Top Left - at the back of the driver, if we agree that the solder pads are "South."  The other 3 holes that look identical are actually sealed. As long as the baffle port is not covered with tape, felt, or Newplast/plasticine, it is open. You can seal it for more bass or keep it open for a little less bass. You can make a modified baffle port by varying the size: Place a tiny square of masking tape over it on the Ear Side of the baffle and puncture it with a a needle. Then you can gradually increase its size with a toothpick for really fine tuning!
 
You can use a paperclip to insure it's open. Push the paperclip through the cup side of the baffle port and it should pass through to the ear side, unobstructed.
 
Nov 6, 2012 at 9:01 PM Post #170 of 2,832
Thanks, but If I covered the baffle port with newplast I wont be able to locate it on the backside of the baffle, is it Ok to to push a sewing needle through the port from the ear side?  Thanks.
 
Phill
 
Nov 6, 2012 at 9:12 PM Post #171 of 2,832
Thanks, but If I covered the baffle port with newplast I wont be able to locate it on the backside of the baffle, is it Ok to to push a sewing needle through the port from the ear side?  Thanks.

Phill


Yes, you can insert the needle or paperclip through the baffle port from either side without causing any damage to the driver.
 
Nov 13, 2012 at 12:32 AM Post #173 of 2,832
Anybody have any of the proper rite-aid super duper awesome cotton? Or something real close? If not, I'll be forced to order this stuff :/ I'd really, really like to get the right cotton.

http://www.amazon.com/gp/product/B004DC3GO8/ref=ox_sc_act_title_1?ie=UTF8&smid=ATVPDKIKX0DER
 
 
*edit*
 
This looks promising

http://www.ebay.com/itm/First-Aid-Sterile-Absorbent-Cotton-Roll-5-oz-01-kg-/261017451390?pt=LH_DefaultDomain_0&hash=item3cc5da3b7e
 
Nov 13, 2012 at 12:43 AM Post #174 of 2,832
Anybody have any of the proper rite-aid super duper awesome cotton? Or something real close? If not, I'll be forced to order this stuff :/ I'd really, really like to get the right cotton.

http://www.amazon.com/gp/product/B004DC3GO8/ref=ox_sc_act_title_1?ie=UTF8&smid=ATVPDKIKX0DER
ir


Chris, Do you happen to have a Rite Aid drugstore in your area? That is where the smaller rolls of the Natural Absorbent cotton can be found. Keith has found that there is some variation, depending on who has produced the cotton for Rite Aid. I do have such a box, but I should send BMF a picture to see if he can confirm that I happen to have the better of the two versions of the cotton.
 
Nov 13, 2012 at 1:21 AM Post #175 of 2,832
Quote:
Chris, Do you happen to have a Rite Aid drugstore in your area? That is where the smaller rolls of the Natural Absorbent cotton can be found. Keith has found that there is some variation, depending on who has produced the cotton for Rite Aid. I do have such a box, but I should send BMF a picture to see if he can confirm that I happen to have the better of the two versions of the cotton.

No Rite Aid's in all of Missouri, I checked :frowning2: 
 
Nov 13, 2012 at 9:07 AM Post #176 of 2,832
Quote:
Anybody have any of the proper rite-aid super duper awesome cotton? Or something real close? If not, I'll be forced to order this stuff :/ I'd really, really like to get the right cotton.

http://www.amazon.com/gp/product/B004DC3GO8/ref=ox_sc_act_title_1?ie=UTF8&smid=ATVPDKIKX0DER
 
 
*edit*
 
This looks promising

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

 
Chris,
 
See my post about this on the T50RP modding page.
 
Good luck!
 
Keith
 
Nov 13, 2012 at 2:07 PM Post #177 of 2,832
Quote:
 
Chris,
 
See my post about this on the T50RP modding page.
 
Good luck!
 
Keith

Chris, 
 
Note that the box/description from your link to the box of U.S. Cotton says .5 oz (.01) gram. That must be a typo but I found 2 items by other sellers on Amazon; one shows .5 oz and the other shows 4.0 oz. 
 
Nov 14, 2012 at 5:54 PM Post #179 of 2,832
Just wanted to post a quick follow up on my DVB #3 build.  I took the fiberglass out of the cups which sounded better to me but I was still hearing a very slight distortion.  I felt that the treble reflector might actually be vibrating since it is only held in place by 2 thin strips of tape.  I removed the treble reflectors and the distortion was gone, midrange is now smooth but i also lost HF extension.  Then I decided to try a small square of doubled up transpore tape on the back of the stiff felt, highs may have extended a little but the mids sound nicely refined now.  Regardless of fine tuning these headphones are a joy to listen to, I have a hard time taking them off.
 
Phill
 
Nov 14, 2012 at 7:22 PM Post #180 of 2,832
Quote:
Just wanted to post a quick follow up on my DVB #3 build.  I took the fiberglass out of the cups which sounded better to me but I was still hearing a very slight distortion.  I felt that the treble reflector might actually be vibrating since it is only held in place by 2 thin strips of tape.  I removed the treble reflectors and the distortion was gone, midrange is now smooth but i also lost HF extension.  Then I decided to try a small square of doubled up transpore tape on the back of the stiff felt, highs may have extended a little but the mids sound nicely refined now.  Regardless of fine tuning these headphones are a joy to listen to, I have a hard time taking them off.
 
Phill

 
Phill,
 
Sweet!  You took my mod configuration and made it your own by tuning to suit your ears, preferences, and audio chain. That's the way to do it.
 
Congrats,
 
Keith
 

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