[brewdog52]

good to hear, thanks waulta. I'll post some pics up later. But I don't know if I really feel comfortable taking them apart, what do you think? will I hurt anything? and will they go back together ok?

 

[ericj]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif I wish. Turns out the metal cup has a flange that sits in a cutaway just the right size with keyways to make sure it's oriented correctly, then a ring of plastic is sonic-welded (looks too neat to be solvent) down on top of it, locking it in place. You basically have to destroy the cup to get the thing apart.

Drat. They had to pick that one part to overengineer.

Quote:

Hee hee. I was thinking epoxy the heck out of the broken strut, then a steel ferrule (like a butt connector) clamped gently over the still-curing joint for reinforcement. The strut's hollow, as it turns out. Thick walls but still hollow. Couldn't believe it. The whole assembly seems needlessly complex for something that ends up being so vulnerable. Want to see a photo?

Hollow, eh? Perfect opportunity for some half-assed reengineering.

Drill through the L/R label, apply a small amount of epoxy to the insides of both halves of the strut, and drive a nail through the center.

Assuming there's significant strut to fit into on both sides of the break, at least.

As for my Pro 30 adventures, I've just replaced the original damping foam with scraps of a heavy woolen blanket cut to the same shape.

An improvement, but there may still be room for more. I suspect that i'm not damping effectively at the outer edge of the earcup. Will have to emulate the Yamaha damping there.

 

[Inkmo]

wowwow! how did I ever manage to miss this thread? Must have been in a stint away from headfi. I'll have to try and get some decent pics of my Audio Technica ATH-2 in here. They ain't the pinnacle of sound, but I give 'em a listen from time to time.

I suspect they could be improved by putting some pads in that will get some distance between the driver and my ears-- they are currently a little muddy and have *no* soundstage. I'm sure were I ever to do that, I'd be opening them up shortly afterwards to stuff fibrous materials in the backs. Just the way Wualta suggested I do the day I bought 'em almost 2 years ago.

edit: did you just hit 1,000 posts-even? Congrats!

 

[tyre]

Quote:

Originally Posted by Inkmo I'll have to try and get some decent pics of my Audio Technica ATH-2 in here. They ain't the pinnacle of sound, but I give 'em a listen from time to time.

Sadly, I parted with my pair of ATH-2's. But they are now in the capable hands of the curator of the Wualta Collection.

 

[wualta]

Quote:

Originally Posted by ericj Drat. They had to pick that one part to overengineer.

Yes. Whilst, and at the same time, underengineering that strut. They didn't even have a good reason to make the diameter as small as it is!


Quote:

Originally Posted by ericj Drill through the L/R label, apply a small amount of epoxy to the insides of both halves of the strut, and drive a nail through the center.

Or get a very long thin self-tapping screw, using the hollowness as a pilot hole. I stress that I haven't tried that. The hollowness is small, about the diameter of a finishing nail.


Quote:

Originally Posted by ericj As for my Pro 30 adventures, I've just replaced the original damping foam with scraps of a heavy woolen blanket cut to the same shape.

Wool blanket? Probably not dense enough, but it'll keep the driver warm.

Quote:

Originally Posted by ericj An improvement, but there may still be room for more.

Good to hear you consider the change an improvement, and yes, I think you'll find there's more performance to be had.

Quote:

Originally Posted by ericj I suspect that i'm not damping effectively at the outer edge of the earcup. Will have to emulate the Yamaha damping there.

It's always better to damp any vents or grilles that lead to the outside. Bass suffers if you don't. That's something I learned modding my Pro 30 twenty years ago; it's why the Pro 30's two circles of vents are covered with felt as part of the mod, and why the vents on the Yamaha are covered too (by the factory).

Here's the Pro 30 with the "pro" mod for single entry. Not pretty, but with this arrangement, if the cord got caught while I was on the job, the phones would simply be ripped from my head; using the stock Y-style cable routing, the cables would be strained at the point of entry, their most vulnerable spot. Not to mention that the yokes that hold the earcups are all plastic and break fairly easily. I used to mod my Sennheiser HD 414s the same way for radio duty.

It uses a 38mm driver that looks like this:

.

 

[ericj]

This is the damping solution i've settled on with my Pro 30 for now. To do better I'll have to actually print up patterns to cut more accurately.

They sound pretty good now. Won't be unseating any of my favorite cans, but they're pleasant. I could see wearing them in public if only to be obtuse.

The first disc is one of the original foam pads. second is a disc cut from a scrap of a heavy wool blanket. The other pieces are very high density (but thin) wool/rayon felt.

 

[matt fury]

Hey, I got ATH-2s, and I don't think that I even realized that they were orthodynamic. W00t!

PS: If I've posted about my ATH-2s in this thread before, ignore that.

lol

 

[wualta]

Here's a sequence showing the disassembly of the damping pads and the original foam pads. Everything's pretty squashed after being inside for 20 years, and the foam and felt have both molded themselves to the inside of the cup. They eventually resemble the vacuum-formed soundproofing pads installed in cars at the factory.

Interestingly, the Pro 30 is vented not only around the circumference of the black plastic driver cup but also, very sneakily, around the circumference of the aluminum cap. You can just see a tiny gap in the photo in my previous post. Here's a photo (by JadeEast) of the Pro 30's public face without its snazzy aluminum cap. Strange but somehow beautiful.

Much better mechanical design than the Yamahas, as you'll see.
There are [only] 3 decent-sized rustproof screws holding the cup halves (earcup and driver cup) together. As usual, the screw heads are hidden underneath the outer circumference of the earpads, which do not have to be removed to gain access. The sequence begins with the earcup facing down and the driver cup (the part with the aluminum cap) lifted off.

(1) What you see at first is all felt:

(2) We've removed that felt disc you saw on top and a smaller black original foam disc that was underneath it (it's visible at left); they covered the cap vents.

(3) We've removed the ring of felt that covered the circumferential vents. You're seeing the original main disc of foam the 'phones came with. Now it's squashed like everything else and no longer makes a very good spring.

(4) I've taken that original foam from the photo above and turned it upside down to show the felt damping disc that was underneath, next to the driver.

(5) We can't forget the auxiliary foam spring necessary to hold the felt damping disc tightly against the driver. This wasn't necessary when the 'phones were new, but it is now. If you look closely you'll see that the pink foam shown is mostly closed-cell (too many sparkly highlights) and therefore unsuitable. So this is for illustrative purposes only. If you can get some aquarium-filter "fishfoam", use it.

(6) Finally, here's the driver with its integral damping pad sitting in its clamp. There's an actual gasket underneath that seals the driver to its baffle-- very important for bass.

As I was finishing this up I saw that ericj has posted photos of his damping bits. Compare and contrast among yourselves.

Again, the aim of this mod, as with all my mods, was to improve the sound but to be completely reversible. For example, the large factory foam disc could have its center cut out so it could be dedicated to the task of keeping pressure on the vent damping ring, but I wanted to keep everything as it was so modders would have the option of going back to stock.

Team Critical Damping!


UPDATE: It turns out that the extra-dense felt ericj found in the remnant bin at the fabric store was too dense for the Pro 30. I've added a warning about the signs of overdamping to post #83. Fortunately, fabric stores all seem to have the cheap acrylic felt that I've been using. About a dollar a sheet, comes in a wide variety of colors. I bet that dense felt would be perfect for the Fostex T20v2 and Yamaha HP/YH-3 and YH-50, though.

UPDATE 2: I noticed when I reassembled my Pro 30 that it had developed a tendency toward overly ripe midbass, thus the advice to add fresh stiff opencell (aka reticulated) foam to keep the damping layer firmly pressed against the driver. The foam needed is fully open-cell and ~6-13mm thick. Ideally it should project at least twice as far above the clamp as the height of the clamp itself. This is to keep from pulling the large factory foam disc in from the perimeter. The factory black foam disc shown above is about the minimum thickness needed, but I don't recommend using it because its age renders it prone to collapse-- some of mine are as flat as a piece of paper. In fact, it wouldn't hurt to replace all factory foam with new stuff.

INTERESTING THOUGHT: Hmm, a loose damping layer pumps up midbass... could come in handy those times when you need to add some warmth to the sound of a particular 'phone...
.

 

[wualta]

Quote:

Originally Posted by matt fury Hey, I got ATH-2s, and I don't think that I even realized that they were orthodynamic. W00tl

Excellent. Same driver, near as I can figure, as the Pro 30. Here's the ATH-2-busted-open thread. Put a felt disc over the back of the driver (under the wires), stuff a stiff piece of foam in the back of the cup to hold the felt tight against the driver, and see what you think. Don't like it? It all comes out again, no harm done.

.

 

[wualta]

Quote:

Originally Posted by brewdog52 I don't know if I really feel comfortable taking them apart, what do you think? will I hurt anything? and will they go back together ok?

I didn't have any trouble my first time. I figure if I can do it, anyone with the right size Phillips screwdriver can do it. Just don't force anything. Disassembly of the HP-1 has been detailed by a helpful Nederlander, Joop Nijenhuis:

http://home.hccnet.nl/joop.nijenhuis/headwize/rhp1e.htm

I'll assume the YH-1000 is at least similar, for the moment. You don't have to remove the earpads to take the cups apart; just peel them back a little where the photos show the screw heads are (scroll down to the bottom of the page).

.

 

[ericj]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif As I was finishing this up I saw that ericj has posted photos of his damping bits. Compare and contrast among yourselves. The only thing I'd suggest is to cut a small disc of that dense black felt and put it next to the driver. Then the wool, then the foam, etc. etc.

Ah, well, the way I'd stacked it, the large disc of felt was directly against the driver. The smaller pieces were on top of that, as well as the blankie, and then the dark disc of foam. All this together made it slightly challenging to close the capsule.

For kicks I've reconfigured with a small disc of felt right against the driver, followed by the large foam disc, followed by the small one, and then finally the large felt disc. So, a bit more similar to your configuration.

Your felt might be thicker than mine, my felt might be more dense than yours. Impossible to tell i guess.

 

[wualta]

UPDATE:
Quote:

Originally Posted by ericj Your felt might be thicker than mine, my felt might be more dense than yours. Impossible to tell i guess.

Too true! Eric sent his Pro 30 on a cross-country trip here to The Lab and we found that yes, his felt was denser than the cheap acrylic stuff and sure enough, it was enough to kill the bass and boost the highs, though the transient response was so crisp it broke my heart to break them back down to merely flat response.


By the way, since we're on the subject.. General rule for adding a damping disc: Your prime directive is to make sure that any and all air coming out the back of the driver must go through whatever you're using as an acoustic resistance. In other words, an acoustically transparent spring (made from some kind of opencell foam) must firmly and uniformly press the damping disc against the driver. The alternative is to glue the disc directly to the driver, but we're all still learning, and I'm not ready to declare an end to experimentation yet.

Inkmo, glad to have you back. Long time no 'mo. Hope everything's clickin'.

 

[matt fury]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Excellent. Same driver, near as I can figure, as the Pro 30. Here's the ATH-2-busted-open thread. Put a felt disc over the back of the driver (under the wires), stuff a stiff piece of foam in the back of the cup to hold the felt tight against the driver, and see what you think. Don't like it? It all comes out again, no harm done.

Thanks for the tip. As soon as I find some time and grow some balls, I'll have to give it a go. Gotta ask though, what happened to the "To be continued..."?

 

[wualta]

Quote:

Originally Posted by matt fury Gotta ask though, what happened to the "To be continued..."?

http://www.head-fi.org/forums/2376787-post5.html post

Last sentence.

.

 

[matt fury]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif http://www.head-fi.org/forums/showpo...36&postcount=5 Last sentence. .

Oh no! I'm sorry to hear it. All the best..there are definitely more important things than head-fi!