T50MKIII

Discussion in 'Headphones' started by MuZo2, Oct 4, 2015.

  1. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    @Biodegraded Did you swap pads too between channels?

    Don't forget that one channel has the cable input. This is generally not perfectly sealed, so it can affect the response to some degree. That it adds additional parts inside one cup also has a minor acoustic response.

    If not that, it's likely pads. And if not that, it would be some oddball sort of material variance or misconfiguration.
     
  2. Biodegraded

    Biodegraded Friend

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    No, I didn't swap anything, just flipped them over on the coupler.

    Yeah, good point, the cable input's on the left, which certainly <del>changes</del> reduces the volume of that enclosure if not the seal...

    Update: Switched pads L<->R, channel imbalance maintained the same shape but INcreased slightly.
     
    Last edited: May 26, 2020
  3. dBel84

    dBel84 Friend

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    I have to say my bet is the drivers - that curve shift would be very hard to impact to that degree if both drivers were to measure identically.

    I know that this is a total pia suggestion - but you might try swapping drivers ( leave them attached to cups ) - unsolder, flip and test again.

    I am with you on this, if it is the driver - nothing you do will change their imbalance.
     
  4. rendyG

    rendyG Acquaintance

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    I had similar problems with my drivers, although nowhere near as significant.. This could be due to loose/overtightened driver housing. The bass imbalance seems too much though, so there could also be problem with a seal or something. From my experience tightening the screws changes mainly the dips in lower midrange (example 450hz in your graph).
     
  5. spoony

    spoony Spooky

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    This ^^^
    The membrane is either tighter or maybe has a crease. If you're feeling adventurous you could try a driver reassembly, it's not difficult but the magnets are very strong and you have to be extra careful.
     
  6. Biodegraded

    Biodegraded Friend

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    Thanks for the suggestions guys - yeah, the size of the imbalance does seem more consistent with a driver issue. I'll keep playing with things today, but if no cure I think I'll exchange this pair in the hope of getting a better match rather than risking driver-assembly surgery at this point.

    Edit: Out of stock at all stores and at supplier until July 15. Screw it (or rather, unscrew it) - let surgery begin!
     
    Last edited: May 27, 2020
  7. spoony

    spoony Spooky

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    Consider using tape or clamps before unscrewing the last 2 screws of the assembly, then grasping it firmly before separating the 2 halves, the magnet assembly tends to try to align itself through the membrane.
     
  8. mdr30

    mdr30 Acquaintance

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    Don't know if this has been discussed, but isolation differences between ear/cup, pad/cup can cause these phenomenons. Make sure everything is sealed/ventilated the same on L/R.
     
  9. Biodegraded

    Biodegraded Friend

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    LOL - were it not for your warning, even my spidey-strength & speed might not have been enough...

    No obvious problems I can see here. I'll swap L & R front magnets when putting them back together though and see what happens.

    [​IMG]
     
  10. dBel84

    dBel84 Friend

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    Nice looking drivers!
     
  11. Biodegraded

    Biodegraded Friend

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    Here they are after re-assembly. I did swap the front magnets around as stated above, but I doubt that had much to do with it. More likely just different tension on the driver-sandwich screws, as suggested by @rendyG above. Some little wobbles through the lower mids on L, but not concerning.

    We have a modding candidate!

    [​IMG]
     
  12. dBel84

    dBel84 Friend

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    Job very well done
     
  13. spoony

    spoony Spooky

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    That's pretty decent matching for starters!
     
  14. gixxerwimp

    gixxerwimp Professional tricycle rider

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    If it was the L channel that had less bass, I'd say try plugging the 3.5mm cable jack with some silicone as I found that to affect bass response. But since it's the other way around, then I don't know. Are they brand new? If used, maybe some modding has been done? Open up the baffles and take a look inside.

    Edit: "Note to self: check if there's another page of posts before replying" o_O
     
  15. Biodegraded

    Biodegraded Friend

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    That's something I'll do during modding for sure. From inside the cup, the hole does look impressive when there's no cable plugged in.

    Thanks everybody for the suggestions and encouragement - have to say I was surprised by the magnitude of the difference made just by disassembly & reassembly. Looking at the result, both channels changed a bit: L bass extension is now reduced, R increased. When reassembling, I started with a corner screw, then the diagonally opposite corner, then a side screw and its opposite, etc., trying to get about the same torque (by hand, of course) on each; and then going around in a final loop. (squeezing the two sides pretty hard between thumb & forefinger while getting the first couple of screws in - like spoony said, the magnets really don't want to be in their correct relative positions!).

    [​IMG]

    The pic above is from Innerfidelity. The little clips on the sides are very fragile, and are redundant anyway because the screw-holes have recessed lugs that locate and secure the two halves of the driver sandwich. I broke the first clip accidentally, but then snapped off the rest to ease disassembly.
     
  16. Biodegraded

    Biodegraded Friend

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    Progress...
    • Stock pads
    • 6 of 8 front vents taped over
    • Thin 2-ply TP (no expense spared!) in front of drivers
    • 4/2 layer gauze/paper bandage taped behind driver (like in the 3rd photo here, but different material)
    • Cotton wool stuffed inside cups, pretty full and covering lower halves of vents (had to do this iteratively to get decent channel balance in the bass):
    [​IMG]

    The main effects vs stock are flattening out the bass through lower mids and taking down the 10k peak - but also broadening the dip in the upper mids.

    Compared to HD6XX:

    [​IMG]

    So far I'm not minding the stock pads for comfort. I have Brainwavz angled ones on order, but nobody knows when they'll make it out of Hong Kong; and I have plasticine coming for the back of the baffle-plate. Might also try taping up one or both of the remaining front vents to extend the sub-bass.

    Any ideas on how to bring up the upper mids? Rug liner?
     
  17. spoony

    spoony Spooky

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    My resource has been pad swap + cosmetic sponge pad damping behind driver inside the cup, the ones that look like this:

    [​IMG]

    It's a very dense, rubbery open-cell foam.

    I use a hole punch to make a vent that I align with the driver vent, experiment with the diameter to move the bass resonance up and down the spectrum.

    I think this measurement was with T50RPmk3 + cosmetic pad with 5mm hole + stock pads with no TP:

    mod.jpg

    Flat plate coupler. I've found this driver to interact with the pinna somewhat, with a resulting increase of the 2-3 KHz range, I wouldn't aim for a flat line there without measuring on-ear or tuning against a known reference by ear.
     
  18. Biodegraded

    Biodegraded Friend

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    Thanks - they look like a better solution than the gauze. Do you cut them square to size and tape them over the back of the driver (presuming they're bigger), or leave them as they are and just let them squish into place when screwing the baffle plate back into the cups?
     
  19. spoony

    spoony Spooky

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    Both work as long as the back of the driver is wholly covered. Some of them fit exactly between the posts and don't move around when re-assembled, I favor those. You can always add more stuff with diminishing returns (plasticine, more damping on the back of the cups, etc).
     
  20. Biodegraded

    Biodegraded Friend

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    I think I found exactly the things: 5.5cm diameter (which fits exactly between the 4 posts in the cup), 7mm thick. I punched a 5mm hole for the driver vent and removed the cotton wool, but left the front TP filter and 6/8 front vents taped up as before. Here's the result in red vs yours in brown (roughly aligned in the upper bass through lower mids):

    [​IMG]

    Not too different from my previous one. Still a big apparent dip in the upper mids, but I think you're right, there might be some ear interaction - with a frequency sweep I hear some difference but not that much between these and the HD6XX, and certainly not a 9 dB climb from 4 to 5.5 kHz. I'll wait with interest to see what new pads will do.

    Subjectively this didn't seem as clean in the bass as my previous mod, so I might put some cotton balls back in (and plasticine).
     

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