Fostex T60RP Teardown

Discussion in 'Headphones' started by purr1n, Oct 8, 2020.

  1. purr1n

    purr1n Finding his inner redneck

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    To put an end on speculating blah blah blah on the T60RP, I've decided to buy one and tear it down. The T60RP appears to be very similar to the T50RP in many respects. From the outside, the major differences are the wood cups, the 4-pin connector (should one want to run balanced from the amp), and a suspension headband. The stock sound is a bit different from the T50RP, but will we get into that later. First let's have a few photos.

    DSC01825.JPG
    DSC01827.JPG
    DSC01826.JPG
     
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  2. purr1n

    purr1n Finding his inner redneck

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    Taking the pads off, the baffle design looks to be a bit different as well. It looks like Fostex may have a taken a page out of the Drop T-X0-ii with the foam inset. However the foam is ring is much wimpier: it doesn't cover the entire baffle area around the driver, and the foam is of much lower density. TBH, I don't even know why Fostex bothered as I doubt it does all that much.

    T60RP
    Wimpy foam ring
    DSC02084.JPG

    Drop T-XO-ii Baffle
    "15" thickness foam baffle insert
    [​IMG]
     
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  3. purr1n

    purr1n Finding his inner redneck

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    The inside of the cups is interesting. The vents are sealed off with a layer of felt. This itself will affect the bass response. The area right directly behind the driver looks like be some kind of "meta" material that may absorb sound waves or cup resonances. The difference is that Foster isn't as insidious as KEF to market it so shamelessly as seen here: https://www.superbestaudiofriends.org/index.php?threads/new-kef-ls50-meta.9918/page-2#post-319581.

    DSC02340.JPG

    The back of the driver looks interesting. I know many T50RP modders have played around with this, but I don't recall a T50RP driver with selective venting. I am not sure if this is a good thing yet.

    DSC02341.JPG
     
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  4. Philimon

    Philimon Friend

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  5. purr1n

    purr1n Finding his inner redneck

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    I took these very quickly without being as anal-retentive as usual for quick baseline, knowing that I would be exploring ways to mod this into something fairly decent sounding. The T60RP seems to have better, that is more normal frequency response than the stock T50RP. Last time I remember, the T50RPs tended to be really bassy with a scoop in the presence region (also seen here) and a slight return in the mid-treble. (It's hard to say because of the variants). The stock T60Rp mostly just sounds bright.

    Fostex T60RP
    Frequency Response
    miniDSP EARS (SBAF comp)
    upload_2020-10-8_13-32-29.png

    [​IMG]

    This is interesting!. From what I understand, the T50RP driver has no suspension. The more porous paper on the T50RP driver may explain why it's so f'ton bass oriented. The T60RP looks to control the driver with more of an air cushion via it's thicker paper, but with a vent, maybe to emphasize a certain frequency, perhaps the mid-bass?
     
    Last edited: Oct 8, 2020
  6. Biodegraded

    Biodegraded Friend

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    T50RP mk2 had the porous paper; T-XO-ii, T50RP mk3 and now T60RP have the thicker paper with the single vent.

    From the Innerfidelity and a lot of other measurements indicate that compared to the 50 mk2, the mk3 is boosted around 100 Hz but falls off quickly below, whereas your FR of the 60 (what coupler and comp, btw?) seems more even through the bass than either of the predecessors.

    Another difference between the mk3/XO-ii and mk2 was the front baffle, which has 8 vents around the edges (the outside of the fat foam ring). Can't tell from your photos - does the 60 have (m)any? That could also account for some of the bass difference.

    Is the 60 cup volume larger than the 50 mk3/XO-ii? Looks like it in various photos.
     
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  7. purr1n

    purr1n Finding his inner redneck

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    The T60RP baffle does have the same eight vents outside of the foam ring. The volume does appear larger with the wood cups. This could account for the bass difference - broader mid-bass boost with more extension.

    The first thing to start is addressing the highs. The significant boost will probably mean at least some front damping. Not ideal, but at least T50RP takes front damping better than MrSpeakers headphones where the dynamics are killed.
     
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  8. purr1n

    purr1n Finding his inner redneck

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    Here the effects of 2ply Kirkland TP over the driver. The highs are better, but the 3k-4kHz dip is still there.

    YEL = stock
    GRN = 2ply TP over driver
    upload_2020-10-9_11-29-53.png

    Now, lets add Brainwavz Angled pads on top of that. FWIW, the stock pads suck and are kind of shallow. The dip is better addressed, but yikes, that bass!

    YEL = 2ply TP over driver
    GRN = 2ply TP over driver and Brainwavz Angled Pads
    upload_2020-10-9_11-32-39.png

    I'm getting the feeling that the T60RP may be a tough cookie to crack. The highs still need some work, but I am hesitant to apply thicker front dampening. I'm going to go with the old trick and stuffing the inside of the cups to see what happens.
     
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  9. spoony

    spoony Spooky

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    Yes, you will see improvements on bass elevation and fill out the 500 Hz dip.
     
  10. purr1n

    purr1n Finding his inner redneck

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    Ugh. This with the Brainwavz Angled pads, 2ply TP over the front of the driver, and a big chunk of memory foam inside the cup (always worked for prior T50RP versions). 1kHz onward is nice though.

    upload_2020-10-9_12-58-5.png
     
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  11. Philimon

    Philimon Friend

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    Open up the t-x0mkii for inspiration since they both use t50rpmk3 driver/baffle?

    Edit: I mostly wonder if t-x0ii modified the back of driver damping and its one hole vent.
     
    Last edited: Oct 9, 2020
  12. purr1n

    purr1n Finding his inner redneck

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    I gave the T-X0mkII away. Perhaps a light touch with the foam like what I did with the TX0mkII is the way?
     
  13. JK47

    JK47 The Beer Houdini

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    Maybe cotton balls, I think I used one and a half in each cup on my MKIII's.
     
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  14. purr1n

    purr1n Finding his inner redneck

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    This is with the Brainwavz pads, 2ply TP, and a small 1" x .o75" chunk of memory foam. Now we are getting somewhere. Maybe a bit more padding in the insert around the front of the driver.

    upload_2020-10-9_13-35-40.png

    Note: do not cut additional holes or remove the stock paper on the back of the driver. It totally screws things up (midrange peak, upper mid dip). I can kiss one driver goodbye already, unless I can find the same exact type of paper.

    This is getting to be a bitch. Wish Drop still sold their T-X0-ii or folks picked up on how good it could be with very simple mods (everything needed included in the box): https://www.superbestaudiofriends.org/index.php?threads/fostex-t-x0-ii-headphones.7972/

    Drop page here (the Drop failed): https://drop.com/buy/drop-fostex-t-x0-v2-planar-magnetic-headphones
     
    Last edited: Oct 9, 2020
  15. spoony

    spoony Spooky

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    You can always tweak stuff to taste with enough elbow grease, I salvaged my MK2 pair with micropore, felt and cosmetic pads after removing the stock damping paper. The new paper is too thick to block the venting hole as well without losing all bass. Things to try are firmer, more breathable materials (stiff craft felt?) directly behind the driver so you can make a breathable 'buffer' between the driver venting and your absorption materials. You can poke a hole in your denser materials to allow some airflow between the cup vents and the driver vents. You can use less dense stuff.
     
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  16. purr1n

    purr1n Finding his inner redneck

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    I tried Creatology felt (too breathable) and foam (not breathable) with the same stock cutout pattern. Ultimately, I just don't have the time since I have more interesting gear coming in.

    I'll follow up with the above solution on one driver that works and take it where I can with existing materials. Or maybe I will send to @rhythmdevils to experiment.

    The keep it simple easy to do still lies in the domain of the last Drop release. I'm chalking this up as a fail in respect to the time constraints I put upon myself. Or at least some half-baked ideas to be pursued.
     
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  17. Philimon

    Philimon Friend

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    Last edited: Oct 9, 2020
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  18. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    Bah what was Fostex thinking replacing the driver damping of the MK2 it was perfect. They went with something too thick then had to cut a piece out to compensate. This seems half baked compared to the T50rp mk2 driver.

    differential (uneven) driver damping can be a good thing because it changes how the driver is moving and could be calculated to stop a driver resonance by lessening the pressure on that particular spot on the driver. But they already used expensive equipment and considerable effort to eliminate driver resonance in the T50rp driver. I think it was a quick attempt to get more treble and then “oh shit we need more bass ok just cut a hole in the driver damping we can’t afford the time to reinvent the driver damping material.”

    you really don’t want to be covering the front of the driver if possible. I honestly would rather mod a T50rp mk2 than this. Everything I see here looks like a misstep except for the possibly thicker material on the cup vent but that’s easy to do yourself.

    baffle vents on an ortho? No no no. Except for that one hole right next to the driver which works for reasons I won’t go into.

    fail
     
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  19. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    Also the cup volume couldn’t be bigger because the enclosure isn’t bigger as far as I can tell from the pictures and a wooden enclosure couldn’t possibly be thinner than the T50rp plastic enclosure material. Unless the enclosure is much bigger the cup volume has to be smaller which damps the driver and gives you more treble and less bass (and smaller soundstage btw). A smaller cup volume is part of how Smeggy tuned his Thunderpants.

    Looking at all this I’d rather mod an mk2.
     
    Last edited: Oct 9, 2020
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  20. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    I believe a lot of what you describe as bad design choices were used in the Drop T-X0 v2. In and of itself, it wasn't great, but with the simple mods @purr1n mentioned, it was pretty darn good. One of the better, though not the absolute best, sounding T50RP variants I'd heard and cheap.

    I don't disagree with your thoughts in general. I think they're generally good design rules to follow. But you can make these odd choices work in tandem surprisingly well on these T50RP variants with just a wee bit of tweaking and the right materials. Well enough to the point you'll scratch your head and contemplate if what you thought you knew was only part of the truth.

    Then again, when messing with orthos, I find them all so goddamn variable with how they respond to mods...
     
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