[daveDerek]

have any of you guys tried also doing a kramer 'socket' mod, and if so what effect does this have upon your other mods?

http://www.head-fi.org/forums/showpo...9&postcount=49

 

[hwc]

In effect, what the "socket mod" is doing is eliminating the high frequency attenuation of the direct sound while still preserving the high frequency attentuation of the sound reflected from the back of the driver.

You could accomplish the same thing by removing the foam altogether from the front of the driver and applying foam to all of the surfaces of the cup behind the driver, including the inside of the grill. This is what I have done with the HD-595s.

I tried foam in front of the driver, which has some sonic benefits, but offset by a loss in detail by attenuating the high frequencies.

Going back to the no-foam configuration and damping the internal cup reflections by lining all of the surfaces with foam produces the best of both worlds. It's actually quite remarkable.

I'm convinced (or perhaps convinced myself!) that the internal reflections show up as a bit of "glassiness" or "glare" or "harshness" in the upper mids and highs -- noticeable on female vocals and particularly annoying on super bright recordings.

If I had the 580s, I would treat the inside flange of the cup and the inside surface of the grille with foam -- it's really easy to tack the foam down with rubber cement. Then, I would remove the foam in front of the driver.

 

[SK138]

hwc, I tried your mod...and all I can say is...(I am speechless for proper words)....just wonderful

The bass is controlled, deep, and very tuneful. The mid is smooth and highs are controlled, never being sibilant. It sounds like a different can. Today I also got MPX3 (toaster) with SLAM adapter and the combination is best I heard yet.

Thanks for the tip!


Quote:

Originally Posted by hwc /img/forum/go_quote.gif I'm thinking more along the lines of "shmooshing" the blu-tak down to form a thin layer that completely covers the large flat outer flange of the housing. Actually, the HD-580 is a pretty darn good design in terms of preventing resonances. The HD580 is so open that bass resonance shouldn't be an issue at all. The issue with headphones is not so much concern about those surfaces vibrating, because the energy levels in a heaphone are pretty low. It's not like a woofer or 5" midrange driver with energy levels that will start surfaces vibrating. So, the main issue is to damp out any reflected high frequencies bouncing around off flat surfaces or sharp edges. To the extent that you have reflections, you will blur the detail of the sound, perhaps audible as a bit of "glare" or harshness. You might be able to accomplish the same thing using rubber cement to glue down a layer of thin foam covering that entire flange. Likewise, a think layer of foam stuck on the inside of the grill will prevent any high frequency reflections from that surface. The grills don't change the sound because of the size of the openings (they are transparent to bass wavelengths), but because of the tiny reflections off all the little edges. That's a high frequency issue and the nature of acoustic foam is that it attenuates more as the frequency increases. From playing around with the 595s, a foam cover between the driver and your ear attenuates those resonances from inside the cup, but at the expense of dulling the direct sounds from the driver a bit. If you can kill the reflected high frequencies from the cup, you can replace the foam with transparent fabric in front of the driver and get the added detail without the "glare" from the reflected sound. BTW, I'd be careful applying the blu-tak on the little piece that carries the lead wires to the driver. That assembly is, from all reports, the mechanical weak point of the 580 design. Sennheisser replaced that whole Rube Goldberg design with a mini-circuit board built into the driver housing on the new generation of the driver in the HD-595. It's not a sonic thing, but rather an assembly and durability thing. The leads solder directly to the circuit board.

 

[hwc]

Glad it worked.

To visualize what's happening, imagine that the driver is replaced by a light bulb that emits light from the front and back. Now, imagine that the inside of the headphone can is a mirror surface. You are going to see light directly from the front of the bulb (good) and a whole bunch of diffuse light coming from the openings in the baffle -- after that light has bounced around inside the can. Sonically, all of those internal reflections (from say 1000hz on up) are just blurring the sound. So applying the foam is like lining our mirror light box with black felt.

So, why use an open baffle at all? Because if you use a solid baffle, you are forming a very small, undersized sealed box speaker enclosure around your ear -- an enclosure that is going to have very funky effects on the bass response. My guess is that an HD580 with a solid baffle would have big obnoxious mid bass peaks. The open baffle is important for tuning the bass, but you really dont want midrange/high frequencies coming through the openings in the baffle.

The improvement on the HD-595s is stunning. They have some advantages over the 580 in driver placement, a more transparent cover in front of the driver, and dead-flat bass response, but are worse from an internal reflection standpoint. Damping the internal reflections makes a huge difference, but preserves the liveliness of the headphones.

I'm noticing stuff I've never heard on any audio system. Things like the sound of a thin-guage pick striking the strings of strummed acoustic guitar. It's a really familar sound to anyone who plays acoustic guitar, but I've never noticed it so prominently in recorded music -- it's the kind of instantaneous attack that would be masked in a living room or by those internal reflections in a headphone. The soundstage gets huge with the damping.

 

[SK138]

Now, you done it!!!! You are going to make me get HD595

I will report back once I get it, mod it, and burned in

Thanks mucho!


Quote:

Originally Posted by hwc /img/forum/go_quote.gif Glad it worked. To visualize what's happening, imagine that the driver is replaced by a light bulb that emits light from the front and back. Now, imagine that the inside of the headphone can is a mirror surface. You are going to see light directly from the front of the bulb (good) and a whole bunch of diffuse light coming from the openings in the baffle -- after that light has bounced around inside the can. Sonically, all of those internal reflections (from say 1000hz on up) are just blurring the sound. So applying the foam is like lining our mirror light box with black felt. So, why use an open baffle at all? Because if you use a solid baffle, you are forming a very small, undersized sealed box speaker enclosure around your ear -- an enclosure that is going to have very funky effects on the bass response. My guess is that an HD580 with a solid baffle would have big obnoxious mid bass peaks. The open baffle is important for tuning the bass, but you really dont want midrange/high frequencies coming through the openings in the baffle. The improvement on the HD-595s is stunning. They have some advantages over the 580 in driver placement, a more transparent cover in front of the driver, and dead-flat bass response, but are worse from an internal reflection standpoint. Damping the internal reflections makes a huge difference, but preserves the liveliness of the headphones. I'm noticing stuff I've never heard on any audio system. Things like the sound of a thin-guage pick striking the strings of strummed acoustic guitar. It's a really familar sound to anyone who plays acoustic guitar, but I've never noticed it so prominently in recorded music -- it's the kind of instantaneous attack that would be masked in a living room or by those internal reflections in a headphone. The soundstage gets huge with the damping.

 

[hwc]

Well, the HD-595 is not as easy to "modify" as the 580. The inside of the cups has a million little shapes. You pretty much have just sit there with a sheet of foam, a pair of scissors, and a can of rubber cement -- cutting and piecing little shapes of foam like a mosaic puzzle. The only big piece is for the inside of the internal grille. Everything else is little tiny pieces cut to fit. Fortunately, the end result doesn't have to look good.

I'm pretty much convinced that the differences in sound between the 595s, 580s, and 600s are almost all the result of differences in impedance, the cup designs, the amount of damping, the placement of the drivers, the materials used for the "silk" covers on the drivers, the grilles, and so forth.

 

[Mrvile]

I'm very curious about your mod design, hwc. I read through all your posts and understand what is trying to be done, but I can't quite visually the actual mod you are doing. Can maybe you or SK138 provide a picture or something illustrating the actual mod?

Thanks!

 

[SK138]

Mrvile, click on my mod HD580 link in my sig below. It's not pretty...but it works for me

Quote:

Originally Posted by Mrvile /img/forum/go_quote.gif I'm very curious about your mod design, hwc. I read through all your posts and understand what is trying to be done, but I can't quite visually the actual mod you are doing. Can maybe you or SK138 provide a picture or something illustrating the actual mod? Thanks!

 

[hwc]

Mrvile:

Well, it depends on the headphone. The basic idea is to open up the headphone (this means removing the grille on the 580s or unscrewing the driver baffle on the 595. Then, take thin (1/8 inch thick) foam -- like the earpad inserts from the 580. Cut out shapes of foam and attach them to all the hard, flat surfaces inside the headphone that you can using a little rubber cement. On the 580, that would be the entire outer "flange" -- on the photos posted earlier, it's the surface around the edge of the cup that has a whole bunch of little squares of blu-tak. Line that whole surface with foam. Then cut a piece of foam and use a little rubber cement to glue it to inside of the grille.

The 595 is a little more complicated because there aren't any flat surfaces inside the headphone. The idea is the same; it just takes a little longer with foam and scissors to cut little shapes to fit all the little nooks and crannies, working around the posts that the front baffle screws into. It's not difficult, it just takes a little time -- maybe a half hour per earcup. If anyone wants to look inside the 595, you can't remove the grille from the back. Instead, you yank off the earpads. Then, lift out the fabric driver cover by slipping a finger nail under the edge and releasing it from the little plastic retainers. Then, use a jewelers Phillips head screwdriver to remove the three screws. Once the screws are loose, the entire driver baffle lifts out, revealing the inside of the cup.

Edit: See SK138's photos above for the locations. I think you could accomplish the same thing by using foam (as he did on the inside of the grille) instead of the blu-tak he used around the perimeter. The foam is easy to apply -- just use the little brush from a jar of rubber cement to smear a little rubber cement on the plastic surface, then slap the foam down. It doesn't stick very much, so it's easy to remove the foam later -- just enough to keep the foam in place. You can't use blu-tak on the inside of the grille, because you don't want to block the holes. The foam is totally transparent to bass, but attentuates mids and high freq reflections a bit.

 

[Mrvile]

Quote:

Originally Posted by SK138 /img/forum/go_quote.gif Mrvile, click on my mod HD580 link in my sig below. It's not pretty...but it works for me

Thanks! Just wanted to know what parts to cover and what parts to leave open. I might try this soon.

 

[Alleyman]

I'm interested in the 595 pictures more than 580. Maybe a step by step guide wouldnt hurt too. Please

...

 

[hwc]

Quote:

Originally Posted by Alleyman /img/forum/go_quote.gif I'm interested in the 595 pictures more than 580. Maybe a step by step guide wouldnt hurt too. Please ...

For the HD-595:

1) Get some foam, by ordering 580 replacement foams or buying Radio Shack replacement headphone foam pads and cutting around the edges to get a flat disk.

2) Get some rubber cement and scissors.

3) Remove the earpads by grabbing one side and giving a swift tug.

4) Remove the protective fabric over the drivers by slipping your finger under the edge and sliding around the perimeter to pop it lose.

5) Remove the three Phillips head screws holding the driver baffle in place and lift the driver baffle out. It's attached with wire leads, but there's enough slack to sit it on the table beside the earcup. DON'T LOSE THE SCREWS!

6). Glue as big a piece of foam as you can onto the inside of the perforated cup. Just brush an little rubber cement on the inside and press the foam down.

7) If you have the patience, just start cutting and gluing little pieces of foam on all the other surfaces of the cup. It doesn't have to be pretty, you can shove the foam around to fit. The only places you can't put foam:

a) There's a little ledge around a third of the perimeter that the driver baffle sits tightly against. If you put foam on this ledge, the driver baffle won't go back in!

b) You have to leave the three screw posts and two more alignment posts clear of foam so the driver baffle can be reinstalled. Either work around them or cut a hole in the foam and slip the foam over the post.

Put it all back together. That's it.

 

[Autochthon]

I have a thought. Back in the day we all made little felt lined wooden boxes in wood shop. The felt was applied by coating the inside of the box with a thin coating of Glue then dumping in finely ground felt and shaking much as you might make Shake n Bake chicken. I suspect that if you were to seal all the critical openings to the driver you might be able to use a similar method to put a thin coating of some rough sound dispersal material on the flat reflective plastic surfaces.

edit aerosol based contact cement comes to mind as an adhesive.
Hmm - On second thought I'm wondering if you can get a thick enough layer to serve your purposes.

 

[hwc]

I think spray adhesive would make a huge mess. That stuff is really aggresssive and tends to go everywhere.

Remember, you've got drivers and connectors and wires and screw holes and stuff that you really don't want to cover in spray adhesive.

 

[Mrvile]

Quote:

Originally Posted by hwc /img/forum/go_quote.gif I think spray adhesive would make a huge mess. That stuff is really aggresssive and tends to go everywhere. Remember, you've got drivers and connectors and wires and screw holes and stuff that you really don't want to cover in spray adhesive.

Spray adhesive might be some of the worst stuff to ever be invented by man. I can't even think of a legitimate use for that crap.

Do not - I repeat, DO NOT - use it on your headphones.