Just listened to some Fostex T50RPs today... WOW!
Dec 6, 2011 at 10:22 PM Post #5,356 of 11,345
That's always been my main criticism...that and the ridiculous price for such a flawed headphone. Same goes for the LCD-3. However, people never seem to hear those recessed mids....


over dampen maybe? i know people have limited high frequency hearing but they should atleast be able to identify the midrange area. that looks pretty bad in the midrange area and seem like i would not like them since i'm all about midrange quality. i do appreciate the work they done on the cups. great work. just not on sonic characters. Fostex should hit the high-end market with their vast knowledge since their first planer full range drivers. i think they have better chance in the high-end market compared to Audeze and Hi-fi man.

 
Dec 6, 2011 at 10:29 PM Post #5,357 of 11,345
       Quote:


The driver is too big. Way too big.


really? i don't know what to say to be honest causing i'm trying to think here how that'll affect it's HF extension. i'm mind-blown right now trying to figure that out. i think i need to fuel-up on some weaties to give my brain a jump-start here.
 
Dec 6, 2011 at 11:03 PM Post #5,358 of 11,345


Quote:
really? i don't know what to say to be honest causing i'm trying to think here how that'll affect it's HF extension. i'm mind-blown right now trying to figure that out. i think i need to fuel-up on some weaties to give my brain a jump-start here.


 
With a large driver, distance between ear and driver's center and ear and driver's edge are highly different - so there is a phase difference in waves coming from edge and center. Hence, they may add to each other or subtract from each other, making dips and peaks.
A "bass lens" should take care of that to some extent, though.
 
Dec 6, 2011 at 11:16 PM Post #5,359 of 11,345
 
With a large driver, distance between ear and driver's center and ear and driver's edge are highly different - so there is a phase difference in waves coming from edge and center. Hence, they may add to each other or subtract from each other, making dips and peaks.
A "bass lens" should take care of that to some extent, though.


i get now. i could picture in my head like a demonstration video and see how your explanation is possible. thanks again!
 
Dec 6, 2011 at 11:47 PM Post #5,360 of 11,345


Quote:
Does the Rp2i config need to remove the bass vent felt or just cover 20% of it by pax mate or electrical tape?



Remove the felt.  I covered the vent with electrical tape on the outside to tune, then taped and paxmated the vent inside and removed the outside tape once the tuning was done.
 
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Dec 7, 2011 at 12:58 AM Post #5,361 of 11,345
Thanks hans and mrspeakers for your replies. Last night, i tried the rp2i with shure 840 pad with the vent closed 3 slot inside with paxmate and 3 slot closed outside with tape and it sound very well but bass is quite bloated. After that, i tried hans config with the felt ( my felt is 100% wool, about 2.5mm thick), the bass port like the previous config and this time, i feel like it lacking the very deep bass. So in my experience is the more i open bass vent, the more bass i get and the more i close the bass vent outside, the more mid bass is  tamed. So i tried this: cover 2 bass slot inside with paxmate and close 3 slot outside with tape and now it's well balance, the bass is deep and tight without bloated. I was wondering is there any mod that get the mid really really foward because using the pad riser which was introduce by HDman, i get very good seal so the bass but midrange is too recessed.
Here are pictures of my config ( this is the previous config so bass vent was closed 1 slot)
 

 

 

 

 
Dec 7, 2011 at 1:19 AM Post #5,362 of 11,345
Quote:
Thanks hans and mrspeakers for your replies. Last night, i tried the rp2i with shure 840 pad with the vent closed 3 slot inside with paxmate and 3 slot closed outside with tape and it sound very well but bass is quite bloated. After that, i tried hans config with the felt ( my felt is 100% wool, about 2.5mm thick), the bass port like the previous config and this time, i feel like it lacking the very deep bass. So in my experience is the more i open bass vent, the more bass i get and the more i close the bass vent outside, the more mid bass is  tamed. So i tried this: cover 2 bass slot inside with paxmate and close 3 slot outside with tape and now it's well balance, the bass is deep and tight without bloated. I was wondering is there any mod that get the mid really really foward because using the pad riser which was introduce by HDman, i get very good seal so the bass but midrange is too recessed.
Here are pictures of my config ( this is the previous config so bass vent was closed 1 slot)


I'm not sure if it would make much of a difference, but my felt looks different than yours (check the link in my previous post). That, and you'll want to use a bit of rubber cement to hold it in place. That tape might be messing with the sound. Also, the hole in my felt is a bit bigger than yours while still only exposing the center area of the driver. Lastly, I have the bottom vent as my open one (tune to your liking). Against, not sure if that makes a difference or not. I get plenty of deep, tight, non-bloated bass if it's called for with the top 3 vents closed and the bottom vent closed about 50-75%. 
 
But, hey, tweak them to your liking! Half of the fun is experimenting.
 
 
Dec 7, 2011 at 3:39 AM Post #5,364 of 11,345
I have a question about a good amp for T50RP. My iBasso D4 portable DAC/Amp combo cannot drive them without the stutter. Here's a link for D4 specs : http://www.ibasso.com/download/2010226223657.pdf
 
The options:
 
1. Leave D4 as DAC and invest in amplifier.
2. Replace D4 with usb DAC/AMP combo. I can use D4 at home, since I have no rig there.
 
If I sell some of my gear, I can go as far as $500, if it is reasonable (is head-fi reasonable anyways) of course. But with so many options I'm totally lost, so I'm turning for the help here.
 
I'm looking at Maverick D1 or Schiit Asgard, are they a good option? Any other good amps or usb amp/dac combos I should know about?
 
Thanks in advance)
 
Dec 7, 2011 at 3:46 AM Post #5,365 of 11,345
You could try two per cup. Paxmate in cup outer rings improves seal.

Thanks! Much more understandable now.
Is the seal between baffle and cup still good that way? There's not much clamping pressure, I suppose..
 
 
 
Dec 7, 2011 at 4:08 AM Post #5,367 of 11,345


Quote:
I have a question about a good amp for T50RP. My iBasso D4 portable DAC/Amp combo cannot drive them without the stutter. Here's a link for D4 specs : http://www.ibasso.com/download/2010226223657.pdf
 
The options:
 
1. Leave D4 as DAC and invest in amplifier.
2. Replace D4 with usb DAC/AMP combo. I can use D4 at home, since I have no rig there.
 
If I sell some of my gear, I can go as far as $500, if it is reasonable (is head-fi reasonable anyways) of course. But with so many options I'm totally lost, so I'm turning for the help here.
 
I'm looking at Maverick D1 or Schiit Asgard, are they a good option? Any other good amps or usb amp/dac combos I should know about?
 
Thanks in advance)
 
 
 


Have you looked into the Objective 2?  Before I stumbled upon it, I was looking into all sorts of amps I couldn't afford, all with their own drawbacks (from the Asgard, to the Lyr, to the upcoming FiiO E15, to the NFB-12, the Matrix M-Stage, etc.).  It's a DIY project, but every once in a while someone builds a bunch and sells them off for ~$150.  It's powerful enough to drive almost anything, yet it also has a low output impedance, so it's suitable for sensitive, low-impedance headphones too.  (When I say "almost" anything, I mean, "HE-6:  Yes," but "Sextets and K1000:  No.")
 
Other than limited commercial availability (and the potential for DIY'ers to make mistakes, etc.), its biggest drawbacks are a cluttered front panel and 1/8" minijack output only.  Because of that, I got the V-Moda cord for use with my T50RP's.  (The designer is making another amp called the Objective Desktop Amp though, which includes 1/4" and RCA jacks...and a few DIY'ers have added them to their O2's.  The upcoming design also includes a high-resolution USB DAC daughter board.)  You also don't want to use the O2 with extremely high voltage inputs, since it'll clip the signal with those, but most inputs are fine.
 
As the name suggests, it was designed objectively using measurements, so it's provably neutral/uncolored and "correct."  No reliable third party measurements have been done yet, but it measures very well across the board according to the designer's own dScope measurements (conducted properly with a real headphone load).  While it doesn't compensate for any headphone's frequency response flaws, it doesn't exacerbate them or add additional flaws either.  It's basically a "wire with gain," but it's pretty unique in that it measures well without being a complete overkill or a "no expenses spared" design.  (Another similar DIY amp to look into would be The Wire, which slightly more expensive and much heavier on the overkill...but I haven't seen any prebuilt ones for sale.)
 
I'm completely happy with mine, even though I don't have a point of reference for subjective comparison.  LFF uses it for his T50RP Paradox too, and it's the amp he used to tune his mod...so apparently it matches up very well with the T50RP.  (I can't weigh in on that personally, since I don't have my Paxmate yet!  I can say that it drives the heck out of the stock cans though.)
 
Dec 7, 2011 at 4:20 AM Post #5,368 of 11,345
Another very good amplifier with inexpensive design is "The Wire". Though kit run has just completed and I don't know when'll another one start. It's somewhat more expensive than O2 though, but seems to have even better measured parameters. Plus the circuit looks more favorable to me.
 
Ah, SobbingWallet has already mentioned it. :)
 
Dec 7, 2011 at 5:15 AM Post #5,369 of 11,345
 
Originally Posted by Cortlendt /img/forum/go_quote.gif
 
I'm looking at Maverick D1 or Schiit Asgard, are they a good option? Any other good amps or usb amp/dac combos I should know about?


The Maverick is using an utterly obsolete DAC chip, so be careful: http://www.head-fi.org/t/446764/maverick-audio-dac-amp/720#post_6333834
evil_smiley.gif

 
 
Dec 7, 2011 at 7:15 AM Post #5,370 of 11,345
Did any one try the T-amp Ta 2024/2021 for the T50rp? I have read that this amp is very cheap (under 40$) and can drive ortho (LCD-2) very well, someone prefer it to the Maxtrix M-stage. The only down side is that you must have some diy skill to recable with the banana plugs to use this amp.
 

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