Orthodynamic Roundup
May 9, 2021 at 12:18 AM Post #26,387 of 27,131
Wouldn't the bass extension die out in this kind of headphone?
Yes, certainly. The center-pinned drivers are extremely low Q factor and extremely insensitive. They manage good mid tone with no seal but actually getting bass out of them requires a small front volume and a vehemently tight seal, arguably tighter than an electrostat.
 
May 9, 2021 at 12:34 AM Post #26,388 of 27,131
Before I settled with putting my Realistic Pro30 drivers into the Marshall Major housing they’re in now, I was experimenting with them in a Beyerdynamic T90 enclosure. I could not get lower bass, let alone upper bass, with that setup. I mostly experimented with various densities of felt and cotton stuffed into the cups.
 
May 9, 2021 at 4:19 PM Post #26,389 of 27,131
You could do a sort of mini chamber of damping directly on the rears of the drivers to make a double room.
Speaking about the Beyer housings of course and the low end stuff.
Had decent success with a couple mods in a large housing with that method.
Pretty sure I used a ring / collar of denser foam to make the walls of the direct-driver-rear chamber, with damping discs inside that.
Basically a two cavity thing.
 
May 12, 2021 at 11:58 PM Post #26,390 of 27,131
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@Music Alchemist hooked me up with a donor beyer w spare pads. RP18 is gonna be nice.
 
May 22, 2021 at 10:09 PM Post #26,391 of 27,131
My once bass deficient pair of HE-400i’s. Sealing the crevices between the driver circumference and cup with bluetac didn’t help. Brainwavz Pleather HM5 Angle pads gave midbass. A little subbass seemed to be added by lining the outer cup with foam (packing material that came with my HE-400se), plugging 3 holes with bluetac by the cable connector, and adding 1mm felt to cover rear driver opening.

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May 22, 2021 at 10:14 PM Post #26,392 of 27,131
My once bass deficient pair of HE-400i’s. Sealing the crevices between the driver circumference and cup with bluetac didn’t help. Brainwavz Pleather HM5 Angle pads gave midbass. A little subbass seemed to be added by lining the outer cup with foam (packing material that came with my HE-400se), plugging 3 holes with bluetac by the cable connector, and adding 1mm felt to cover rear driver opening.

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I used the same foam initially with T20v2 to add bass using stock pads

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May 25, 2021 at 1:18 PM Post #26,393 of 27,131
No ortho mods recently. Just waiting on RP18 for DT880 transplant. Mostly satisfied with T30’s current damping scheme, and the comfort is not too bad after strong-arm headband forming.

The defean velours I suspect are rubber or pleather with an exterior velour lining, which means they are not so porous and explains why I dont lose bass when switching between defean hybrids. The velours are much preferred because they are much slimmer and allow much closer driver to ear distance. Much clearer, smoother upper mids.

Less damping than seen in pics is too little. Lose too much bass focus/control. T30 undamped is still quite good and better than Yamahas overall by large margin. Its been too long since Ive heard Audeze, HFM, and Verum so cant compare but wouldnt say T30 better in any way (possibly except and most importantly in terms of tone). Im currently satisfied with T30’s sound. Knowing the incredible value and rarity makes it extra special.

RP18 I plan to use HFM focus-a pads. Those pads would be too large for T30 but Ill give them a try anyway. If they sound as good as I expect then I might have to do a T30 transplant too. The HFM focus-a are best type of hybrids, the interior ear chamber is velour so its extra porous and allows entire large foam pad to be part of the ear chamber equation. They are also thin (close driver to ear distance) and angled.

edit: :) The extra felt layer at back of cup is nah. Few db increase at 1-2kHz I think contributes to fatigue and a “hard” sound like 6XX. Not worth the little tighter bass trade off. Either reaching sweet spot of technicalities vs tone, or damping and pad combo not optimal. I believe these pads are okay but could be better...
 

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May 25, 2021 at 10:09 PM Post #26,394 of 27,131
Holy crap. Cool to see you guys still going.
Yes, certainly. The center-pinned drivers are extremely low Q factor and extremely insensitive. They manage good mid tone with no seal but actually getting bass out of them requires a small front volume and a vehemently tight seal, arguably tighter than an electrostat.
What kind of bass are you talking about? They'll never have the bloated bass of a T50RP, but with a few dB's of EQ they are perfectly adequate for my preferences with reasonably sized ear chambers and normal clamp force. If I knew how to measure headphones I would, I suppose, but I don't so I can't really show you what I think I've accomplished, I can only tell you. The YH-100 model that I made isn't far off from RP-18's in a Superlux/Beyer enclosure, it just lacks the stereo image SIZE and last bit of detail retrieval. The YH-100's sound really good to my ears once you free them into a circumaural enclosure (good enough to make me forget about Arya's most of the time), but due to the going rate of used YH-100's I don't really recommend buying them when other stuff so close in performance is so much cheaper. Uncovering all the magnet perforations (stock pads cover half of them) really makes the sound more spacious and details jump out more, imho, but compared to RP-18 they still sound slightly constricted, especially with certain instruments. Some sounds/instruments they sound clear as day and then with others there's almost like a grain to the sound. Orchestral pushes them to their limits, but most other music sounds fine.
 
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May 25, 2021 at 11:13 PM Post #26,395 of 27,131
T-X0. Never really liked the sound of these stock, but could not part with them since the serial # corresponded to my birthday. With my current mods, they’re keepers imo.

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May 26, 2021 at 8:58 AM Post #26,396 of 27,131
YH-100 drivers installed into Sony DR-ZX701IP frame. Epoxy putty holds drivers in place on baffles and also seals damped baffle vents. Single layer of Arctic bamboo for damping driver. Sorbothane applied to rears of baffles. Cups filled with Cellucotton rayon fiber. I bought this stuff called Acousta-Stuf polyfill because I forgot what Twaron Angel Hair was called. The Acousta-Stuf did not sound good so I returned it. Then I found this Cellucotton stuff which I used for vaping purposes. This stuff is made to keep chemicals out of women's eyes when they get a hair perm, but I spread it thin and bunched it up to damp the enclosure. Seemed to do its job. It killed the bass when I used too much, so it seemed to act in a similar manner to the Angel Hair.


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I also built a headphone exactly similar to this one except it uses sintered YH-1 drivers. I could probably obsess over mods to make YH-1's sound extremely close to YH-100's. I just feel YH-100's are a little more extended on both ends and they also have more upper midrange and treble energy which sounds closer to "correct" to my ears. I could probably try a/some reflex dot(s) to get the YH-1's closer in this regard. I completely forgot about some of your guys' modding techniques!

But anyone who says center-pinched 55mm ortho drivers have no bass needs to hear these, imo. They're not bass monsters and never will be, but for someone like me who doesn't really appreciate the sound of the T50RP (way too much bass which sounds loose, recessed upper mids and treble compared to other things) these are perfect. They remind me of an Etymotic ER4XR in a full sized headphone.
 
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May 26, 2021 at 9:16 AM Post #26,397 of 27,131
I recently got back on the modding saddle with a nemisis headphone that has been in the attic for about 3 years out of frustration.

Fostex T40RP mkII

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It sounds very tastefully v-shaped. No bass bloat at all.
Almost surprisingly, vocal tonality is totally fine.. it just takes a bit of a backseat.

• Open the rear ports (remove plastic covering the vents)
• Inside of cups completely covered with adhesive felt - leaving just the bottom vent open (opening more vents cuts off sub bass slightly)
• Aftermarket Ori pads
• Paxmate around driver front (make sure to leave the side vent open)
• All stock driver damping removed (this was causing HUGE bass energy around 100-200hz)
• Replaced stock damping with micropore tape, leaving middle and top vents open
• 'Mad dog' style adhesive felt rectangle on back of driver
• Smaller adhesive felt rectangle on front of driver
• 1g of Twaron Angel Hair acoustic filler
• One circle of acoustic filler (arctic cotton/thermolam/whatever you have) inside the ear pad - this does 2 things - treble attenuation and 'spacer' that drastically improves sub-bass response.
• DIY suspension headband - makes the biggest improvement, obviously.

- More pics of mods here - https://www.head-fi.org/threads/fostex-t50rp-incremental-mods-and-measurements.618659/post-16356751
(to avoid some multi-posting spam)
 
May 26, 2021 at 10:04 AM Post #26,398 of 27,131
• All stock driver damping removed (this was causing HUGE bass energy around 100-200hz)
Maybe this is what I've been hearing? The bass is just too much for me. My T50RP mods are very unconventional, however, I transplanted the drivers into a Sennheiser HD535 frame with Brainwavz HM05 pads. I guess I should check the damping scheme.... I know there's arctic bamboo on the back of drivers, but don't remember if stock damping is intact. Grrrr. Can they be helped? I just wonder if bass isn't my thing and they sound perfectly fine to others. Even your measurements look "dark" and overly bassy to me.

I updated the mod to bring down the mid-bass.
Increased quantity of Twaron Angel Hair from 0.30g to 1g
Haha. I was literally just thinking about this. Might have to try.
 
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May 26, 2021 at 10:16 AM Post #26,399 of 27,131
Maybe this is what I've been hearing? The bass is just too much for me. My T50RP mods are very unconventional, however, I transplanted the drivers into a Sennheiser HD535 frame with Brainwavz HM05 pads. I guess I should check the damping scheme.... I know there's arctic bamboo on the back of drivers, but don't remember if stock damping is intact. Grrrr. Can they be helped? I just wonder if bass isn't my thing and they sound perfectly fine to others. Even your measurements look "dark" and overly bassy to me.
In an open-back config like your Sennheiser, I would guess the sub-bass will be almost non-existant, but the mid-bass bloat should still be there, making a VERY wonky bass response... but that's my guess.
As soon as I opened up more vents on my T40, the sub bass just got a bit quieter, so I can only imagine it gets worse the more open-back it gets.
Also the online graphs of the TH-500RP kind of 'prove' this point to a degree - VERY poor bass extension on these.
I would put the drivers back into a mostly closed back shell, or close off almost all the vents on the Sennheiser, leaving three or four of the smallest ones open at the very bottom.
That might start putting things back in order, but I have no idea how it responds in that frame.

Overall the bass 'shelf' on mine is only 5dB louder than the top of the treble peak, so it doesn't sound obnoxiously bassy to me... although I was going for a bassy tuning for sure.
I've got so many neutral headphones, I wanted something a bit more bonkers going in a similar direction to DT1770 Pro or MDR-Z1R.
 
May 26, 2021 at 10:37 AM Post #26,400 of 27,131
In an open-back config like your Sennheiser, I would guess the sub-bass will be almost non-existant, but the mid-bass bloat should still be there, making a VERY wonky bass response... but that's my guess.
Ok, I should have explained the mods a bit. I sealed the back vents entirely with pleather fabric and then lined the fabric with modeling clay, so basically they are fully sealed. Then I drilled a bass port on the bottom, sealed up the cable entry points as well as around the yoke hinges (openings in baffles where yokes attach). It's not so much sub-bass extension I'm worried about, it's the mid-bass bloom that does me in. The mid-bass just never seems to STOP. I'm debating if it's worth $80 to get some Angel Hair shipped my way. I have a feeling if I just stuffed the right amount of Angel Hair in there it would damp the mid-bass enough to make them TRULY listenable for me.

-Edit- Curiosity got the better of me. I stuffed a little Cellucotton rayon fibers in behind the Twaron Angel hair that was already in there. Mid bass seems a bit more tame immediately. I like what I'm hearing.
 
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