Fostex T50RP : Impressions and Future DIY PVC Housings
Jul 11, 2010 at 12:57 AM Thread Starter Post #1 of 23

peli_kan

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I've gotten listen to and compare the Fostex T50RP, stock and modded, to a bunch of other headphones.  Stock, the Fostex were terrible.  I'm usually able to convince myself that a pair of headphones could lend itself to a unique set of user "preferences" but...no.  The midrange was lumpy and distorted, highs were absent, and 100hz and below bass was present but just that.  There was no electrostatic bite that I'd expected, and the sound as a whole wasn't worth listening to.  On the plus side, build quality was superb, and comfort was what you'd expect from circumaural smooth vinyl pads.  User replaceable EVERYTHING was a welcome change from the norm.
 
My mod consisted of 4oz. total of blu-tack against the back of the housing and inside the front plastic face, a 5.5 x 5.5 x 0.5cm piece of dense felt with notches cut out to fit the housing on top of the blue tack, and four total pieces of shredded jumbo cotton balls very tightly packed between the felt and driver. 
 
First, these headphones are HEAVY now.  Unless I turn to lead tape (of which I have heaps) I've maxed out these stock housings as far as mass goes.  I had to tighten the headband lest the weight of the housings drag them off my head.  Secondly, the sound is COHERENT.  Where before nothing made sense, with voices twisting about while rattling and hissing, vocals now sounded real.  Bass is dampened to around Ety levels, while the midrange is now realistic.  There is no treble sparkle, something that I may or may not remedy with a reflex dot.  I'll decide once I've enjoyed enough music with this particular frequency response.  In truth, the treble seems totally in line with the proverbial Ety presentation, which I'd argue to be NOT peaky but instead seamlessly integrated with the rest of the spectrum.  In fact, after A/B-ing with Etys, I'd go as far as to say that a pair of modded T50RP sound very similar when it comes to transparency, frequency response, and blackness of background.
 
I'm happy too hear none of the symptoms of backwave reflection, credit to either the modding or bad hearing skills and expectation fulfillment.  Either way, the mod did its "trick" and I have a pair of clean, closed headphones that punches far above its weight. 
 
I'd like to audition a pair of Thunderpants to see how they compare to my hack job, but even without that I'd be satisfied with what a few dollars in parts have done to these Fostex t50rp.  I will be using PVC pipe ends, very heavy, dense, and rigid, to make my own housings.  With some careful cutting, filing, and black matte spraypaint, I'll have myself a poor man's version of Smeggy's creation.  All credit goes to him for demonstrating what creative craftmanship can do; I'd be merely following in his footsteps.
 
Jul 11, 2010 at 2:50 AM Post #5 of 23
Congratulations on the success of the mod. Please consider tucking it away in the Ortho Roundup Thread (with photos and diagrams, of course) so that the readership who might not want to set up a wood shop might approach the sound of the T50RP driver transplanted into a custom enclosure by cleverly modding the stock housing. Others have tried this, of course, but you might have come up with a unique wrinkle. Eventually, the hope is to have all the mods up on Wikiphonia.
 
Jul 11, 2010 at 3:08 AM Post #6 of 23


Quote:
Congratulations on the success of the mod. Please consider tucking it away in the Ortho Roundup Thread (with photos and diagrams, of course) so that the readership who might not want to set up a wood shop might approach the sound of the T50RP driver transplanted into a custom enclosure by cleverly modding the stock housing. Others have tried this, of course, but you might have come up with a unique wrinkle. Eventually, the hope is to have all the mods up on Wikiphonia.


Thanks for checking in on my impressions, I'd be glad to contribute to both that monstrosity of a thread along with Wikiphonia. 
 
The reasons I chose PVC pipe end caps were that they're cheap, universally available, consistent, accurately finished, heavy, and easily shaped.  There's even the chance that the plastic parts themselves may be softened in an oven and fitted to a metal mold, such as a small cake tin or some other shape.  At that point, raw plastic pellets may be integrated into the process to either supplement or replace the PVC pipe altogether.  In any case, plastics have been overlooked and hold potential. 
 
I fell in love with using ALL CAPS in my original post.  Shall I MAKE this a HABIT?
 
Jul 18, 2010 at 9:27 PM Post #7 of 23
Using a tone generator, I've been testing the effects of clamping pressure, and what frequencies it affects. 
 
With a proper seal, even 20hz was audible with only moderate roll-off.  High clamping pressure increased the loudness of all sounds below 250-300hz, above which proper sealing produced no change.  I wish I could properly attribute decibel increases to each frequency span, but my ears aren't reliable enough... yet. 
 
Jul 24, 2010 at 12:30 PM Post #10 of 23


Quote:
The only question here is what is your source, audio format, DAC and hps amp ?


Good question.
 
FYI, my T50RP's sound quite good stock, they just need decent power.  I will be modding them of course.
 
Sep 1, 2010 at 8:47 PM Post #15 of 23
thanks for the link! so I've:
-removed the nasty felt before the drivers
-removed the felt before the cups side holes
-added some papyrus behind the drivers to kill resonances a bit
 
the mids/trebles are pretty awesome now! the drivers are still too slow to my taste, but PRaT is quite good and the sound is very laid back and not fatiguing.
 
next stops are 1) adding some foam to win bass volume, it really sounds like a tin can atm 2) add some bluetak
 
BTW, how can I know whether I've got the v1 or v2? I don't have the box...and this phone is really bass shy atm.
 

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