[bluemonkeyflyer]

I have never seen a trough in that region with the baffle port open from 100's of measurements of my modded sets and my LCD2s. I routinely get a 3 dB dip at 40 Hz and a trough at 7 to 8 kHz.  Some very clever measurement gymnastics were suggested by symphonic and Arleus using myB&W 803S speakers and McIntosh MX-136. I followed their advice and the results revealed the same dip and trough with the conclusion that they're due to my HRTF aka weird ear shape, I suppose.
 
I wonder if your measurements could be due to your HRTF and/or calibration error? Do you see similar troughs with other 'phones? If not, I'd re-calibrate the audio/measurement chain and repeat the test.  If you cannot solve the puzzle, maybe something happend to your measurement kit.  If you have a multimeter, you could remove the circuit from the box and test all the connections for continuity. If you find a problem or don't have a multimeter, send it back to me and I'll check it over, fix it, and return it, or make a Paypal refund.
Quote:

Another set of odd readings!
The first one is regarding the baffle port...

Spoiler: Baffle%20Port

**LOTS OF SPECULATIONS IN THIS ONE**
 
With regards to the baffle port, unfortunately I wasn't able to get proper measurements on the sub-bass region but one thing I did notice: whatever frequency below 60Hz became consistently higher. Notice the OPEN position the bass drops rapidly after 60 with a deep trough at ~29Hz? Well that is gone.

While certainly such squiggly lines can NOT represent much, but the disappearance of the trough once the baffle port sealed is consistent. Perhaps sealing the baffle port allows better sub-60Hz frequencies presence.

 
The second one is more stretched HM5 specific (may also apply to other pads).

Spoiler: Pad%20Orientation

 
Let me first explain: HM5 pads as well as 840 pads are both smaller and more of a slimmer oval than the original T50RP pads. Positioning them in different orientations may also shift the shape along the inner rim. This test has been tried out with HM5 pads only, and was originally more focused on whether the stitching layout will affect sound... It seems the sound is indeed affected, although be it by the different deformation (sag location) or the stitching line, I don't know.

The region most affected in my setup is here (50Hz ~ 400Hz region also but the readings were not as clearly consistent). Notice that with the outer stitching line facing anything but UP decreases the drop at 3.5kHz, and likewise affects the recovery right after.
 
Another part that cannot be seen in this graph is the 10kHz region, where mine has a peak. The 10kHz (sibilance?) peak is most apparent with the stitching facing up, with descending magnitude in DOWN, FRONT, and BACK, which is about 5dB less than the UP case.
 
These variations have been confirmed for consistency throughout different damping schemes.

 
As always, read relative changes only.

 

[kalbee]

I believe that odd trough is due to the also odd mod I currently have in there. Other 'phones don't have it.
But it certainly can be a measurement artifact more specific to my T50RP due to the shape of my ears in relation to its particular sound or sound emission pattern. With the mic left in the ear I measured many times, taking on/off the headphones just to reposition it as I go. That trough is pretty consistent today when the ports are open. The same can be said with the port closed (mic still there, took off headphones, opened it, and sealed the baffle port), just without that trough.
 
By ear the bass port sealed does give me more impactful bass indeed.
 
I don't think the microphone itself is at fault, more my computer hardware still, or the ambient noise my desktop is ringing off (P.S. its pretty loud). I normally don't look at the readings under 50Hz. I don't think my onboard sound card handles it well. Intriguing that most of my measurements give wavy sub-50Hz readings (thus discarded) except the ones I made for the Q701. HP-1A and SJ5 where the bass extends relatively straight down past 20Hz.
 
I'll try recalibrating again though.

 

[mrscotchguy]

Hey guys, just got my V-moda cable in (not purple or red either! 

)
 
I am truly amazed how bad the channel imbalance was pre-cable-replacement.  I thought if I just fiddled with the stock cable jack enough it would even out... I can rotate the V-moda cable around and have no change at all in either channel!  Super exciting 

 
Edit:  I am not used to this volume level on my right ear, I think I am going to go deaf in the right ear unless I can compensate for the the under compensation of the stock cable.

 

[dorino]

You probably had a bad plug on your stock, if you had channel imbalance. I have none with my stock fostex cable.
 
Does anyone have a picture of the V-Moda cable hooked up to a T50RP? I'd like to see what the 45' jack looks like in context - the V-Moda cable is very nice, from what I recall of the M-80, and I'd love the red one with my Mad Dog.

 

[mrscotchguy]

Quote:

You probably had a bad plug on your stock, if you had channel imbalance. I have none with my stock fostex cable.
 
Does anyone have a picture of the V-Moda cable hooked up to a T50RP? I'd like to see what the 45' jack looks like in context - the V-Moda cable is very nice, from what I recall of the M-80, and I'd love the red one with my Mad Dog.

 
Most likely DeoxIT would have fixed the problem... but this cable was the same price 

 
http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/7965#post_8349262
 
This linky has some picture pron.  I will take a picture later with my gray/black cables when the are not on my head.

 

[nick n]

Quote:

Hey guys, just got my V-moda cable in (not purple or red either! 

)
 
I am truly amazed how bad the channel imbalance was pre-cable-replacement.  I thought if I just fiddled with the stock cable jack enough it would even out... I can rotate the V-moda cable around and have no change at all in either channel!  Super exciting 

 
Edit:  I am not used to this volume level on my right ear, I think I am going to go deaf in the right ear unless I can compensate for the the under compensation of the stock cable.

I wonder how much of what people are attributing driver imbalance has to do more with this cable issue. Even if it is slight, if many are experiencing things like this, would it not be better to get a proven slightly thicker plugged replacement so you can start mods off from square one and adjust them properly each side as you go.  Without the  unknown variables of a known issue/
 
I would hate to think the fussies that spent so much time tuning  get a new cable and have to go readjust things all over again. But then again that's part of the fun I guess.
 
Think I will eliminate this variable for myself soon ( yeah and I call others fussy )
 
How prevalent is the iffy TRS end on these T50's I haven't paid attention to that

 

[wdahm519]

I think the baffle port should always be closed by default before finite tuning is performed because it yields an increase in bass, but not only that, it yields tighter bass.  Opening the cup vents all the way leads to a lot of bass (which isn't always good) but its flabby and uncontrolled.  When you reach that perfect balance with the baffle port closed and the cup vents closed or barely open, the bass is deep, tight, and very controlled.

 

[dorino]

That cable looks very fly. I think I'll get one. 

 

[LFF]

Quote:

I wonder how much of what people are attributing driver imbalance has to do more with this cable issue. Even if it is slight, if many are experiencing things like this, would it not be better to get a proven slightly thicker plugged replacement so you can start mods off from square one and adjust them properly each side as you go.  Without the  unknown variables of a known issue/
 
I would hate to think the fussies that spent so much time tuning  get a new cable and have to go readjust things all over again. But then again that's part of the fun I guess.
 
Think I will eliminate this variable for myself soon ( yeah and I call others fussy )
 
How prevalent is the iffy TRS end on these T50's I haven't paid attention to that

I've been saying the same thing over and over since I discovered the V-Moda Audio cable. It cures the T50RP of the channel imbalance that many people find with the stock cable and is a great solution for those not want to do a full re-cable.
 
The V-Moda cable is also super durable.

 

[nick n]

ordering some now. Got so sidetracked with modding junk I overlooked that. Thanks Appreciate the overconfirmed confirmation, red will have to do

 

[bluemonkeyflyer]

Quote:

I think the baffle port should always be closed by default before finite tuning is performed because it yields an increase in bass, but not only that, it yields tighter bass.  Opening the cup vents all the way leads to a lot of bass (which isn't always good) but its flabby and uncontrolled.  When you reach that perfect balance with the baffle port closed and the cup vents closed or barely open, the bass is deep, tight, and very controlled.

^ +1
 
Closing the baffle port also reduces sub-bass ringing for cleaner SQ.

 

[kalbee]

BMF, is there any preferred material to seal the baffle port? That is, if in your experience that causes any difference.

 

[dorino]

I ordered a V-Moda cable. Quite frankly, unless you want a custom cable or have spools of cable on hand, it's probably cheaper or at least as expensive as buying the parts/cable to make your own.
 
I think the red and black will look quite good with my Mad Dog.

 

[bluemonkeyflyer]

Quote:

BMF, is there any preferred material to seal the baffle port? That is, if in your experience that causes any difference.

 
For temporary purposes while tweaking and measuring, I've used a little square of electrical tape to close the baffle port. For permanent sealing, I've used hot glue and silicone. They work equally well and are still reversible. Whatever you use should completely seal the baffle port and stand the test of time without shrinking, drying, or cracking. Tape is not a permanent solution. As it dries and shrinks, the baffle port will gradually open over time, changing the SQ ever so slowly.

 

[wje]

[Major Depression]
 
While I love listening to the Fostex headphones, I think I love modifying them and working on them nearly as much.  With that said, I desired to re-work another revision and sold off my existing pair.  While I have my HIfiMANs, I don't think I'll be able to use them as I try to go to sleep as my wife will kill me.  The Fostex isolated the music so well.  Now, I just have to wait it out for about 5 or 6 more days.  I was frantically searching Craigslist for some closed headphones that might suffice, but nothing was too appealing for night listening.  Then, I thought it would be pretty stupid to spend $40 to $60 on a pair just for such a short period of time and then to have them go on the shelf and collect dust.  I guess I'll just have to head to bed about 5 hours earlier than my wife, so I can get my music listening in.
 
[/Major Depression]
 
 
On another note, I have never really been a fan of Paul Simon.  I think about 25 years ago, I actually despised his Graceland album.  Compared to the Black Crows, etc. - Paul Simon could do nothing that would appeal to me.  Well, I thought I'd check out the new, 25th Anniversary edition of Graceland.  All I can say is "wow."  With the Fostex T50RPs, the album sounds fantastic.  There are passages with some great percussion as well as some bass beats and finally a bit of side-to-side wavering of some of the tracks.  All of these features in the music really affirmed how capable the Fostex headphones really were.