TH500RP Modding (WIP)

Discussion in 'Modifications and Tweaks' started by Hands, Nov 4, 2015.

  1. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Pyrate MZR
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    If you can get that to work, that might be a good idea!
     
  2. bags

    bags New

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    This was like reading a book, that the last 5 Chapters are missing. What was the final plan? Did the cups of the 00 do the trick? I have a pair, but outside of female vocals and some 3-4 instruments plunking along in some down tempo 80's haze, they sit unused...
     
  3. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Oh jeez, sold mine long ago. The trick is to mostly close the cups (just a little bit of a port!) And add internal damping of choice. Maybe front damping if needed. Like any other T50RP mod, but with more enclosure work.
     
  4. Philimon

    Philimon Friend

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    TH500RP.jpg
    Stock pads foam is very soft and leather rubbery (bought used), don't like. Measurements above are with stock pads. Bass channel imbalance not sure I can hear, but it was measured consistently. The T50RP driver sound I am conditioned to. Probably listened to T50RP variants the most often during headphone hobby. The highs don't seem to bother me for some reason but on other phones those peaks could mean murder. The whole treble valley doesn't really bother me either. Does sound top to bottom duller compared to modded THX00 I was just listening to beforehand. From what I remember, best sounding stock variant of T50RP I've heard vs T50RPmk2, mk3, T-X0mk2, T60RP.

    Will try alternate pads. Will post before/after measurements and impressions of non-specific mods. I think TH500RP has most potential even though drivers are all the same. TH500RP is unique because much more open and larger cup, and driver baffle is semi-open for more tuning possibilities.
     
    Last edited: Jul 16, 2021
  5. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    The T50rp driver was designed to be close back. The engineers of this headphone themselves expressed frustration at a meet that Fostex wouldn't let them design a new driver. This headphone is just a big fat money grab by Fostex. Trying to make an open back audiophile ortho without actually designing one. I wish I had one of these so I could light it on fire.
     
  6. Philimon

    Philimon Friend

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    TH500RP AHl pads.jpg
    Accessory House lambskin pads. Channel imbalance persists. I feel I can hear a bass imbalance. Treble channel imbalance is related to my measurement rig (left is reference) and possibly the headphones. Will have to open these and see if something came loose. Maybe Fostex would sell replacement drivers.

    Based on @Hands experience, I was hoping for extra quality control on these drivers. They were definitely priced and presented as luxury. The headphone packaging was the biggest box I've ever seen for a headphone - that includes Koss 95X which came safely bundled with an energizer.

    @rhythmdevils No doubt these need to be damped up just like all other T50RP. Just wondering if more rear vents is more better. TH500RP cups stock I would consider semi-open, and way more semi-open than other T50RP enclosures. Would be interesting to try THX00 cups on these.

    I wonder why they decided to give these extra leaky driver baffles... Not unusual for a headphone, but only T50RP variant to get that treatment. I'll add a pic later.

    The highs peak adds a little painless fake detail. Not too shimmery, piercing, or distracting. And overall they don't appear to come up over bass or mids so it's not horrible.

    I like them! I keep going back to T50RP driver, sometimes rebuying same models to retry modding. Or buying thinking that I'll keep stock. Last time I tried that was with a T-X0 that I reluctantly sold to rhythmdevils. Not this time buddy!

    edit: BTW @E_Schaaf figured out a good mod on his first attempt. Good understanding of fundamentals. I just meddle until finally improvement or breaking or bored.
     
    Last edited: Jul 17, 2021
  7. spoony

    spoony Spooky

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    That bass imbalance could be fixed by re-seating the driver membrane in the capsules, I did this with one of my pairs:

    1) Loosen (don't remove) the following screws until you feel the top of the enclosure is able to move slightly:

    Untitled.jpg

    2) Put your mouth against the driver vent and blow / suck to make the membrane move, shift and crinkle (I don't think the membrane could tear by doing this but don't do it too hard just to be safe).

    3) Tighten the screws carefully in a crossing pattern, trying to achieve the same tension everywhere.

    That may do it.
     
  8. Biodegraded

    Biodegraded Friend

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    Phil, do try @spoony 's driver realignment suggestion (or maybe it's evening up the tension). Based on that, thanks again to him and @rendyG , I turned this into this.
     
  9. Philimon

    Philimon Friend

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    TH500RP AHL imbalance fix attempt.jpg
    Thanks @spoony ! Looks like bass imbalance is fixed but maybe a +1-2db louder right channel. However, could be my measurement rig or the pads. Inspecting the pads I noticed left side appears to be a tiny bit thicker. I have an extra set of AHl pads I could try... And I can check my old 6XX measurements to see if there is a level imbalance in my rig. Oftentimes I don't even measure RIGHT side of headphones as I've not refined the compensation curve for that side (lazy).

    Pics coming in a minute.

    edit: I did the membrane reseating procedure for both sides. Loosening the screws didn't seem to make driver come loose at all. There are also 4 tabs that tightly hold down / sandwich the driver as well...
     
    Last edited: Jul 17, 2021
  10. Philimon

    Philimon Friend

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    [​IMG]

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    THX00 cups do not fit well. Cup and driver baffle lip do not meet, like 1/2cm gap.
     
  11. Philimon

    Philimon Friend

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    Attached is demonstration of channel imbalance in my rig using trusty Sennheiser 6XX. Zoomed-in graph. Each set of 6XX L/R measurements shows the same imbalance. These 6XX were lightly modded (spider removal and damplifier pro).

    I'll try matching AHl pads with extra set to see if that helps explain the larger disparity.
     

    Attached Files:

  12. Philimon

    Philimon Friend

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    That one LEFT pad was fatter than the other AHl pads I had around, so I switched with another L pad. Looks pretty consistent now with my regular EARS L/R imbalance as tested with HD6XX. Left side should be closest to SBAF EARS compensation. Thanks again @spoony and everyone. That's all for now folks.

    BTW I did all my recent THX00 mod measures with that fat L pad too. So, highs should be a little lower than shown. I thought it was odd, which is why I had included right side measurements too in that THX00 thread.
     

    Attached Files:

  13. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    From the pictures, it looks like the T50rpmk3 came from tweaks to the driver and enclosure for the TH500rp. The driver damping is the same, and they added baffle vents to the MK3. Stupid Fostex. The MK2 is the better headphone. The only good thing about the MK3 is the addition of lips on the baffle for proper earpad attachment.
     
  14. Tekker

    Tekker Facebook Friend

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    I had the TH500RP in 2017. Sold it off because of the huge lack of dynamics and recessed vocals.

    Had the Denon Dx000 pads on them
     
  15. Philimon

    Philimon Friend

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    T50RP mk2 and mk3 have tiny pressure release vents, 1-2 tiny holes in the driver baffle. Mk3’s new earpad mounting lip were leaky, designed to allow front side pressure relief (or whatever), which added another variable to modding (simply seal off if wanted to remove new variable). Mk3’s other difference was the rear of driver damping scheme (the white paper filter with one square hole uncovered) which was the other major tuning difference vs mk2. Stock for stock, I recall the mk3 sounding much more balanced than mk2. Drivers were all the same, it was just the enclosure / tuning tweaks by Fostex.

    TH500RP does not have those tiny pressure release vents (ports?), instead has those big holes with some paper filter covering.

    @rhythmdevils You are free to borrow my TH500RP. I know you cant buy them new anymore without paying some OOP premium. Can only find at reasonable prices used, which generally hovers just above new street price back when TH500RP were normally sold. Dont light them on fire though. I bought them out of curiosity, mod challenge, and to use. Always wanted one but seemed way overpriced, then realized recently from mod adventures how important enclosure is to a headphone so wanted to try. Fully modded it seems @Hands already discovered that its just another T50RP. Any redeeming quality considering price is negligible. Rather go T60RP for the hard woody sex appeal. BTW, did you ever complete your T60RP?
     
  16. Philimon

    Philimon Friend

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    Even if they are totl stock T50RP, the more I mod for bass the more closed in they become and sound and the less I like them. Have a HE400s arriving soon I could compare before selling. Create classified soon, @rhythmdevils gets dibs if to light on fire. Also prefer my other planar the T30 because smoother freq response, larger driver, and very open including magnet array in comparison.
     
  17. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I’m good thank you though @Philimon f**k the TH500rp
     
  18. Philimon

    Philimon Friend

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    [​IMG]

    I cannot get a frequency response nicer looking than stock using a more open configuration. So, I've tried semi-open, sealed, etc. and cannot get anything as nice as @Hands or @E_Schaaf . This puzzle is too difficult for me.

    Front and rear of driver baffle are each half of equation. More damping means more technical ability but not more nicer to listen to since I lose something in the tone etc. in exchange. I don't have the mod power. And I have lost patience. I have some other projects and headphones I want to work on.

    Best I could do is attached. This is more open than stock, no filters on rear of driver or closing driver baffle. Couldn't tell if I preferred to stock but knew it wasn't ideal.

    Trying without cups was to try and test if 8-10kHz had anything to do with some cup reflection, but no - still lurks there. That peak is hard to hide.:
    https://www.superbestaudiofriends.org/index.php?threads/fostex-t50rp-mods-compendium.7824/
     

    Attached Files:

  19. spoony

    spoony Spooky

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    Yep you need a tighter seal around the ears to 'preserve' the little bass energy / displacement there is, if the sound is not agreeable to you like this, perhaps it's not worth your time. IME the the strenghts of this driver lie in the relative neutrality that can be achieved, 'blackground', separation and speed, not dynamics or overall percussive engagement.
     

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