Fostex T50RP Incremental Mods and Measurements

[bluemonkeyflyer]

Quote:

It's Windows version, V5.01 beta 10, there is also beta for lin/mac, but they're completely untested, as author says.
 
Have you properly level-matched Magni and Dacmini during your test? Safe margin for level matching is only 0.1dB.
I'm personally though more inclined for a very high-feedback gear, NFB takes care of any errors for sure, while in low-NFB stuff, there are some elusive things..
 
Yes, I've used your measurements.

 
I vaguely remember reading about V5.01 beta for Mac in July 2011. I opted for V5.0 because it had been tested. I may dust off my older Dell and try it with V5.01 for Windows.
 
I did not accurately level-match the Magni and Dacmini for my semi-controlled comparisons made to satisfy my own curiosity. I matched them by ear, only. I like the entry level Magni/Modi combination and the priceerformance is impressive.
 
Happy Holidays to Everyone.

 

[wje]

Just a couple of pictures for the group.  Here are some shots from a single-entry cable re-work that I did a week ago.  This cable job enters the cup at a single entry point at the bottom of the cup and completely eliminates the 3.5mm connector within the cup.  In fact, the connector was removed and everything in that regard was properly sealed up.  I have an oval plastic cap - which I've used in the past to seal up the jack hole in such a situation.
 
 

 

 
 
May all of you have a great holiday.  May you all have peace, regardless of how you celebrate the events.

 

[Nevod]

Quote:

 
I vaguely remember reading about V5.01 beta for Mac in July 2011. I opted for V5.0 because it had been tested. I may dust off my older Dell and try it with V5.01 for Windows.
 
I did not accurately level-match the Magni and Dacmini for my semi-controlled comparisons made to satisfy my own curiosity. I matched them by ear, only. I like the entry level Magni/Modi combination and the priceerformance is impressive.
 
Happy Holidays to Everyone.

From what I understand, you just have to substitute the program's jar file with beta jar on Mac. Don't think it actually has any fatal bugs, what we're interested in is anyways not OS-related, just internal calculations.
 
By the way, do you use your headphones with crossfeed? To me, it seems that DBV#3 would be pretty much untolerably bright without it (for me, at least).
 
Funny thing is that after full crossfeed and equalisation, my headphones now have about the same tonal balance as completely without all that.
The current mod sounded quite bright, but not intolerably so. Then I added stereo convolution with HRTF, made sound much darker and a bit muffled, even, but more comfortable. Then I added EQ compensation for the system used to record HRTFs,  - mainly only bass boost. Produced some insanely bass-full sound, not realistic at all, everything sounded as if recorded during earthquake, and unemotional at all. Then I added EQ curve to even out my HPs, and the tonal balance was for the most part just as before anything, more detail though, so some pits in former FR were filled I think. 
 
Got to do the mod proper on holidays. EQ is good, but native is better. Looks I'll have to do some excess damping like eltocliousus, as Beyer pads are probably more like Stax pads than Shure.
 
Thanks! Happy Holidays!

 

[chrislangley4253]

Quote:

 
By the way, do you use your headphones with crossfeed? To me, it seems that DBV#3 would be pretty much untolerably bright without it (for me, at least).

Methinks your dampening is off. I had a similar problem before I got the right cotton and I got the right amount of dampening worked out. Just my .02

 

[Nevod]

Quote:

Methinks your dampening is off. I had a similar problem before I got the right cotton and I got the right amount of dampening worked out. Just my .02

I do have problems with damping, but they're of another kind. I have way too elevated bass, +20db by 20hz. Hence, they are actually dark, but to me, they're bright.

 

[stozzer123]

Guys, 
 
Pulled off the stock paper that was covering the back of the driver and it sounds terrible.  Whats the best option on modding now?  or have I completely buggered it?
 
cheers

 

[eltocliousus]

Quote:

Guys, 
 
Pulled off the stock paper that was covering the back of the driver and it sounds terrible.  Whats the best option on modding now?  or have I completely buggered it?
 
cheers

 
I've had to compensate for the same issue a few times, two layers of transpore over the back of the driver to replace the damping paper does an ok job, this is with a treble relfector and two layers of stiff felt aswell, what modifications are you currently using?

 

[wje]

Quote:

Guys, 
 
Pulled off the stock paper that was covering the back of the driver and it sounds terrible.  Whats the best option on modding now?  or have I completely buggered it?
 
cheers

 
I've also used the following configuration:
 
- One layer of micropore medical tape over the left "3" vertical squares on the back of the driver.
 
- One layer of micropore medical tape over the right "3" vertical squares on the back of the driver.
 
- One layer of heavy craft felt over the "3" middle vertical squares.  This was attached with double-sided tape by carefully placing it on the metal bars that frame the 9 panels on the back of the driver.
 
I've also used transpore medical tape with a small square of a heavy magazine cover (the glossy type) over the middle square.  The transpore was used to cover the back openings of the driver.  I've used one layer, as well as two layers of transpore tape in the past.
 
Both solutions are quite viable for handling your situation.  Many of us who have experimented with the Fostex mods for quite a while have some similar conclusions that if one desires a deeper level of bass, the back paper would need to come off, as you have done and then use some of the suggested solutions for covering the back of the driver.  Yet, there are others who have been able to accomplish their respective mods by keeping the rear paper in place on the driver itself.  Though, I suspect in some cases, a possible arranged sequence of pin pricks to open up the paper a bit, might be viable at allowing a better bass response without removing the paper completely.
 
Finally, a final method that has also been used when encountering a headphone with the driver paper missing was to use a square of glossy magazine cover over the middle square of the driver, then put two thicknesses of heavy craft felt over the back of the driver.  This, too, has also yielded some pretty good results.
 
If you can, get your hands on some transpore tape, micropore tape, a small amount of a glossy magazine cover as well as a piece of heavy craft felt.  Those materials should able to be obtained for $10.00, or less.  Then, do some experimenting to see which particular option matches your desired sound better.  When going through this process, just use masking tape to hold the baffle of the headphone onto the ear cups.  Then, place your ear pads on and run it through some tests.  The masking tape will allow you quick access to the insides of the cups for further adjustment.  When you have a sound that you are happy with, then install the four screws to hold the baffles onto the cups, re-install your ear pads and enjoy.
 
Finally, I'll have to say, all of the above content would not have been possible if it were not for BlueMonkeyFlyer, who has taught me 97% of Fostex headphone modifying through his well documented posts in these threads.
 
Enjoy!

 

[MuZo2]

I received  my TR50 last week,  I have build measurement mic with panasonic 61a and linkwitz  phantom power supply.I measured Westone 3 and RE-Zero and the results of FR available online match mine. But the results  from bluemonkeyflyer for stock TR50 donot match.
bluemonkeyflyer did you use the mic placed in your ear? what smoothing have you used ?  for waterfall did you use default parameters?

 

[MuZo2]

OK seems there was too much pressure as  headphone was stretched now with small pressure the readings are quiet close to bluemonkeyflyer.

 

[bluemonkeyflyer]

Quote:

I received  my TR50 last week,  I have build measurement mic with panasonic 61a and linkwitz  phantom power supply.I measured Westone 3 and RE-Zero and the results of FR available online match mine. But the results  from bluemonkeyflyer for stock TR50 donot match.
bluemonkeyflyer did you use the mic placed in your ear? what smoothing have you used ?  for waterfall did you use default parameters?

 
The measurements won't match.
Yes, I placed the mic in my ear.
I didn't use smoothing for incremental measurements unless indicated at the bottom of the graphs.
Yes, I used default settings for waterfalls. You can download any/all REW .mdat files from my Google Docs links and run the data analysis with different "time windows."
 
How did you measure IEMs? I have not been able to get any reliable measurements using the artificial ear canal.
 
 
Quote:

OK seems there was too much pressure as  headphone was stretched now with small pressure the readings are quiet close to bluemonkeyflyer.

 
I was just about to suggest that you re-read the first paragraph of Post #1 in this thread. You cannot reliably compare your measurements to mine or anyone else's for a host of reasons. You have discovered just one variable that affects measurements - clamping pressure.
 
Here are some additional variables to consider when making and interpreting measurements:
 
1. Headphone postion on head: high, low, back, forward
2. Amount of hair on head; size of head; size/shape of ears
3. Microphone position or angle placed in ear: A few millimeters and degrees make a big difference.
4. Depth of mic placement in ear: ear canal fully sealed vs partially sealed produces significant differences in measurements. Again, a few millimeters make a big difference.
5. Type of IEM ear tip used: Foam tips introduce error by artificially increasing the bass frequencies and diminishing treble frequencies.  Triflange tips artificially increase treble frequencies. I showed this effect in Post #1. 
6. Size/type of caps used in phantom power supply
7. Design of the phantom power supply
8. Smoothing vs. no smoothing
9. Measurement "Window" time
10. Graph resolution chosen - 10 dB vs. 5 dB
 
I think it's important to practice making measurements until familiar with REW and confident that the measurement method is standardized as much as possible. Make measurements of other headphones to serve as Baseline or Reference. Reference measurements will help with interpreting measurements of each mod.

 

[MuZo2]

 
Quote:

 
 
How did you measure IEMs? I have not been able to get any reliable measurements using the artificial ear canal.
 
 

I am using 8mm dia tube and 30mm length and measurements of Westone 3 match well.
I am using linkwitz mod on one of capsules and also linkwitz simple phantom powersupply.
 
I finished the mod, have used cotton damping and reflector dot. Quiet happy with low end and mids, but highs are not there where I want them,I guess I will have to get hold of fiber glass. I will also order twaron angels hair which I can expect in 2nd week of Jan.

 

[bluemonkeyflyer]

Quote:

I am using 8mm dia tube and 30mm length and measurements of Westone 3 match well.
I am using linkwitz mod on one of capsules and also linkwitz simple phantom powersupply.
 
I finished the mod, have used cotton damping and reflector dot. Quiet happy with low end and mids, but highs are not there where I want them,I guess I will have to get hold of fiber glass. I will also order twaron angels hair which I can expect in 2nd week of Jan.

Can you link to the design of your artificial ear canal and your linkwitz simple phantom power supply?
 
RE: Your mod...What type of cotton did you use, how much, and how did you prepare it?
 
Please post some measurements and description of your mods.

 

[MuZo2]

http://www.mp3forkidz.com/mic/mod.html
 
This is link to linkwitz mod.
 
I used Riteaid cotton balls, Separated them evenly and layered  them in cups. Not sure how much weight they are.Followed the DVB #3 instructions for rest of the steps.

 

[chrislangley4253]

The cotton is frustratingly important. Seriously, I couldn't believe how important.. It's just dumb cotton, right?