Just listened to some Fostex T50RPs today... WOW!
Dec 1, 2011 at 4:50 PM Post #5,208 of 11,345


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I can see how modding them would affect and improve bass and possibly mids, but how does adding damping do anything to salvage the total latck of treble detail? without that these phones are pretty useless. But if modding does affect the treble, they may end up sounding great.....trouble is, not many of these posts say anything about what their mods do in any detail other than, "this is better, this is great". Talk about useless subjective statements !  HOW is each mod better ?



I wouldn't neccesarily say mine is better than the rest but I do have independent measurements...
 
Paradox:

 
Names TOTL headphone:

 
Another namesless TOTL headphone:

 
I like my Paradox because to me it sounds very flat, natural and neutral while maintaining great bass slam and fantastic detail and resolution across the frequency spectrum.
 
Dec 1, 2011 at 5:06 PM Post #5,209 of 11,345


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Yes, it is 3 conductor.
 
Craig, I had seen that cable, and may buy one though I only use 1/4" for the amp end. Anyone know how long this cable is?
 
I was really hoping for a connector that would work that I could wire with whatever i wanted to use. I have about 10' of Mogami mini quad that I was going to start with.
 
 




Ran across this connector the other day and was wondering if it would fit? Hate to waste $20+ to find out and will probably just recable.
 
http://www.moon-audio.com/diy-audio-parts/other-connectors/oyaide-3-5-stereo-mini-plugs.html#
 

 
Dec 1, 2011 at 5:08 PM Post #5,210 of 11,345
Very impressive LFF. You're in that competition at inner-fidelity right? 
 
M
 
Dec 1, 2011 at 6:23 PM Post #5,211 of 11,345
I can see how modding them would affect and improve bass and possibly mids, but how does adding damping do anything to salvage the total latck of treble detail? without that these phones are pretty useless. But if modding does affect the treble, they may end up sounding great.....trouble is, not many of these posts say anything about what their mods do in any detail other than, "this is better, this is great". Talk about useless subjective statements !  HOW is each mod better ?


lack of treble is lack of absorption in the cups. the cups diffuse the treble very easily and since each frequency was resonating like crazy in the cups it was causing cancellations at certain frequency bands from the resonance reflecting back into the driver itself. that's why it's important to prevent resonance in speaker cabs cause resonance cause cancellations. when you dampen the speaker cab not only do you make the drivers believe it's in a bigger box but absorption of usually midrange to air(upper treble) frequencies takes place as well since it slows down the frequency to a halt to prevent any type of resonance or you can have it completely absorb.

fiber glass is one of the cheapest and best man made absorbers. you can a buy 15''(width) x 9''(thick) x 25'(length) at home dept for 10 bucks. that hell of lot of fiber glass. there is slight difference. if looking for it it's marked ''attic'' or ''basement''. only difference there is thickness of the fiberglass. attic insulation is always thicker than basement version and reason why it's shorter in length but it's the amount of thickness that matters the most. can use it for headphones as well and works great. don't need much at all....maybe less then 1'' thickness or 1'' thickness for complete absorption down to 20hz(this is just a rough guess. i have no idea on ''exact'' measurements). it takes lot time and error but you learn to get the hang of it.

i finally got my lazy self a 25' roll of 9'' thick fiber glass cause i'm finally gonna work on my bass traps i been procrastinating for months now. don't need it all since my area not very big at all so gonna experiment with it on my fostex. just tiny bit of fiberglass alone should kill and completely absorb down to 20hz. 20khz is no worry about absorbing since upper high frequencies are fast and very short wave lengths so it takes very little to absorb them. the sub-bass is always the challenge at absorbing and where ''thickness'' matters.
 
Dec 1, 2011 at 7:09 PM Post #5,213 of 11,345

Is this measured with/without a dummy ear? I ask because I've noticed that the T50RPs don't have a bump at 2-3 kHz like my other headphones do (Superlux 668b for example). Is 3 kHz where the ear canal resonance is? So it should show up on Tyll's measurements, but not when measuring the headphones against e.g. the floor? 
Quote:
I wouldn't neccesarily say mine is better than the rest but I do have independent measurements...
 
Paradox:

 

 
@thelostMIDrange
My experience so far is that mods shelve the FR from about 1 kHz down. Below is an example of a quick in-ear measurement of the stock cup (+some foam, can't remember), using a MDF baffle instead of the stock baffle, vs a wooden cup.  Green is the wooden cup, which is probably overdamped here.
 
It seems to me that we can do more to bring the cliff down to earth than to raise the treble. The enclosure should have less of an effect on high frequencies, whose wavelengths are small compared to the length scale of the enclosure.
 

 
 
 
Dec 1, 2011 at 7:35 PM Post #5,214 of 11,345
OMG, this phone sounds so horrid stock ^^
 
I've slapped that isolation foam into a brand new T50RP: fantastic isolation but yay, the sound is mushy, bass shy and the mids are unbearably resonant and sparkly...so I've decided to add newplast in the baffles, no improvement huh? I guess the secret to deep bass lies in proper foam lining inside the cups, you really don't want any plastic to be in contact w/ the back wave...I will install AcoustiPak tomorrow, and possibly add that isolation foam on top
evil_smiley.gif

 
It's true that once you open the side vents, the SS doesn't make sense anymore...and I get to hear my computer fans and my dog snorting, so keeping them closed might end up being a totally acceptable compromise after all.
 
PS: deep bass is far more percussive and louder on my Akasa lined pair, but there's something I prefer w/ the isolation foam hah! I guess you can only get the exact sound you want by A/B'ing several pairs indeed, the brain DSP smoothing things out too quickly
very_evil_smiley.gif

 
Dec 1, 2011 at 9:29 PM Post #5,219 of 11,345
well seems like combination of fiberglass and polyfill works best for me. the fiberglass does all the absorption while the polyfill adds more ''space'' so to say to make the driver believe it's in a larger enclosure improving imaging,dynamics and soundstage. i'm pretty happy with my results and defiantly......defiantly done...well for now. seemed just adding loads of fiberglass made it ''over-dampened'' , while good combination of fiberglass over the open bass ports(yes, i opened the bass ports) and polyfill seems to give me satisfactory.
 
Dec 1, 2011 at 9:52 PM Post #5,220 of 11,345


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Recabled with 4 core MIC cable (first time, went well)
Completely gutted the cups, applied Response Super Sound Deadener (5.0mm thick & foam combo mat, $29.95 from Jaycar)
 

 
 
1.5mm Butyl (same as dynamat), 3.0mm Foam (like paxmate but heaps better)
This stuff is really good.
 

 
Gutted the cups, removed the gay little box, sealed up the hole with Response, lined it tightly with a sheet of Response evenly on both cups.
 

 
Lined the earside with Response and the plastic risers.
 

 

 
Afterwards, I slit one of the vent stripes and bored it out for the bass tuning from the outside, this Butyl is much easier to work with than Dynamat.
Electrical taped the 840 pads, right on the edge with the risers.
 
Conclusion.
Bass is so tight, like I have not herd before on any of the previous mods. On bass heavy tracks, you could feel the drivers moving a bit, now they stand firm, no shaking about, just the music.
Mids are more laid back, some may not prefer this, I like it not to in your face, but definitely not what I would call D7000 recessed.
Highs are silky smooth now, all harshness is now gone, vocals are really clean.
 
The best way I could describe the sound, is that it is a cleaner sound, as if they are a completely open can. My take on this is that, open cans have less or no reflections from a closed enclosure, so you only here the music and not a muffling reflection. Room correction technologies curb reflections because they muffle the sound when they bounce back, so essentially open cans sound airy because they have no reflections, not because the sounds goes out into the air.
 
So my take is that if in an enclosed cup you can kill all the reflections, essentially you are performing the same task as an open design, but most manfactures find it to cost counter productive to spend much money on the acoustical treatment inside the cups and opt for an open design, mush easier and less costs to produce. Hence the reason many of us DIY modders always seem to open up the closed cans to modify them, like the D7000, which I must say drastically improved after treating the insides.

I think I can safely say that my experience was very similar. I used a spray on sound deadener inside the cups and used some natural cellulose sponge material tight up against the driver to dampen it.
 
My results are almost exactly as you described in yours. With the exception that my mids are not laid back at all, but just forward enough to be perfect for me. The result is so close to an open can. I actually grab these more often than my HD600's (paired with a modded Matrix M-stage). And I love an open sound.
 
I am torn between humility and being convinced that my mod is the s*&t!    I really need to connect with another T50rp owner/modder locally to compare. Suffice it to say I have not even been tempted to open them and tinker since I hit on this configuration.
 
-Dogwan
 
 
 

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