"Open Alpha" DIY project from MrSpeakers

Discussion in 'Headphones' started by Pyruvate, Nov 18, 2016.

  1. Baten

    Baten Friend

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    That capture looks really nice spoony. Good work :O
     
    • Agreed, ditto, +1 Agreed, ditto, +1 x 2
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  2. spoony

    spoony Spooky

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    Thanks! There's still a few things I'd like to improve upon but time has been scarce:
    • Better sub-bass extension
    • Remove a bit of glare that remains at ~6-8 KHz
    • Midrange distortion (maybe this is driver-specific and there's better samples out there)
    Things I'm not sure can be fixed here:
    • Slight macrodynamic compression
    • Slight lack of microdynamic nuance (plankton)
    That said, there's still a bunch of things I very much enjoy about this headphone:
    • Deep 'blackground'
    • Clean decay and fast midrange transients
    • Images come from everywhere and 'float around' in a way I enjoy
    • Decent clarity
    Hope some of this will be useful to people messing with these cans, they're a lot of fun.
     
    Last edited: Jan 25, 2023
  3. Biodegraded

    Biodegraded Friend

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    What amp(s) are you using with them? Recent experience has me thinking the Tx0RPs are significantly harder to drive than their specs would suggest, perhaps more so than other planars with impedances in the same order. @purr1n has mentioned this elsewhere too.
     
    Last edited: Jan 25, 2023
  4. spoony

    spoony Spooky

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    Jot2 @ high gain, single ended. Previously Vali 2 @ high gain. They 'woke up' with the extra juice when I first got the Jot2, I've still to be arsed to convert them to balanced to get more juice out of the amp. This is a relative measure to the high-efficiency dynamic drivers I got installed in my other headphones, perhaps an unfair comparison.
     
  5. Philimon

    Philimon Friend

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    T20RP driver baffle and stock under pad vent foam, stock flat pads.
    Im no expert obviously so cant make any inferences about cup or driver resonances or quality of measurements. fwiw:
    [​IMG]

    [​IMG]

    T20RP micropore VS T20RP butt naked.jpg
    T20RP driver CSD.jpg
    T20RP driver micropore CSD.jpg
    T20RP paper removed CSD.jpg
     
  6. BearFacts

    BearFacts Rando

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    The issue that I am struggling with on my open alphas is they sound very dark and seem to lack clarity, even compared with my T50RPs that include a mayflower-like mod (similar mod using materials that I had on hand). I currently have the cups lined with paxmate, two layers of loose wool roving, paper still on the back of the driver but with a 12 mm X 10 mm patch of stiff felt stuck on. Using 1 mm wool felt on the ear side of the baffle. The patch of stiff felt brought more sparkle, but still pretty veiled sounding headphones. All holes are open....closed 2 or 3 but didn't seem to make much difference. Baffle sealed to the cups with caulking and pads are alpha dogs.
     
  7. spoony

    spoony Spooky

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    I've had mixed results using ear-side filters, most of the time I get agreeable treble level but blunted transients and indistinct imaging, that's why I favor pad rolling before ear side damping. As an exercise, try removing any front damping from all your pairs and A / B, plus points if you can switch the pads between them too. General darkness could be due to a scooped presence region which is fixed with direct damping of the driver's back side, that's why I use the cosmetic pads, they raise 2-5 KHz.
     
  8. spoony

    spoony Spooky

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    This is great, shows that the scooped presence region is not the result of a destructive interaction with closed cups, and probably has more to do with diaphragm damping, as shown: more damping = less scoop. The trick lies then in achieving a good FR balance without killing dynamics or producing other undesirable effects.

    BTW: I also found that achieving a flat or level-measuring presence region in a flat-plate coupler led to kinda hot upper mids with this driver to my ears, I balance that region by ear and using other headphones as reference.
     
  9. Philimon

    Philimon Friend

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    And that’s where it gets tricky. I like modding headphones because theyre like a puzzle game. But I get impatient and stumped pretty easily so Im ready for the solution now. Ill try my best to copy you (and company from mk3 thread), thanks. I should probably start by getting new pads.
     
  10. BearFacts

    BearFacts Rando

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    Thanks. I probably wasn't clear - I have a square cut in the wool felt the same size as the driver, so the wool felt on the ear side isn't filtering. In any case, I'll do a bit of pad rolling to see how that works out....have some shallow pleather and thick velour pads that I can try.
     
  11. spoony

    spoony Spooky

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    Most of the fun is in the journey ;)
    FWIW: Not claiming that my mod is better than anyone's, it's worked for me and it's probably worth a try to see if any of the tricks I used are down your alley (preferences and all), but it's likely you'll arrive at a different place when you are happy with the results.

    I'd remove anything that covers the front when making judgement calls about clarity or doing A/B comparisons. I used to have one or more 'doggie treats' installed with certain deep pads, but then found out that a pair I had just started modding sounded clearer than my extensively modded pair and it was down to the front obstructions, when I removed the dots the clarity was leveled but of course I now had hot, spiky treble due to the pad choice.
     
  12. BearFacts

    BearFacts Rando

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    Good call on ear side materials impacting clarity. I removed the 1mm wool felt with the driver size hole cut in it and clarity improved immensely. With just the plastic surface of the baffle, there was too much sibilance/sparkle, so I just put some card stock with a hole cut out for the driver in there and that tamed things quite a bit. I wouldn't have thought that a gram of 1mm thick felt around the driver would impact things as much as it did.

    I also tried velour pads and some shallow pads. Although I'm not a basshead, the velour killed the bass a bit too much, and the shallow pads did not sound as full as the deeper, angled alpha dog pads, so I'll stick with this configuration for now.

    Thanks again for the good advice.
     

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