Naked HD650's -- HOLY SHEEAT! - Page 3

I rather suspect it's more like an "acoustic foam" that is either acoustically transparent, or close to it. I just don't see Sennheiser or any reputable headphone company using something that affects the sound negatively in an objective sense, and I don't believe "we know more than they do." But if someone wants to do this, knock yourself out of course... can't tell ya what to do with your own set of cans.

Note that there's always a chance the material you choose (pantyhose, socks, etc) has some subtle properties that degrade the sound in ways you may not consciously notice. If you're not absolutely positive it's acoustically transparent, why risk it?

Edit -- here's what JaZZ had to say about it in another thread:

Beagle:

With my setup, its the highs that was most clearly affected. Tizz, for lack of better words, sounds like a tizz instead of a diffused one with the stock foams. Clarity has been noticably boosted as well. Bass sounds the same to me. As a matter of fact, my silver-dragoned HD-650 is now slightly on the bright side (with the same mid-treble dip though) and I like it!

I don't know if these foams are 'specially engineered' to tune the drivers of their specific headphones. The HD-650 as well as my previously owned HD-580 and HD-570 feature the exact same foam materials. I'm more inclined to perceive Sennheiser's choice of foam is mainly economic. They just have to ensure the foams are reasonably thin so as not to impose considerable sonic colouration.

Regards.

I'll give you a quick run through of how this is done, its easy. Buy a pair of thin black stockings or use your girlfriends, shes never getting them back!


Completely remove earcups for added ease, or leave in situe if you want. To remove, unplug cable, rotate earcup 90º(driver pointing down) it will click and you can remove from headband. Note left & right

You have to take the pads off. To do this just grab a load of the velour(not any hard surround) and pull, it unclips and comes off, take out foam underneath.

Cut out a big square portion of the stocking, much larger than the foam. Use the leg, its much thinner. I cut off like a 6" 'tube' and then cut down an edge and open out into a square.

Place this square of stocking over the driver, like making a pie, leave plenty overlapping. Clip the earpad back into place, use another person to hold the stocking taught if needed...

Now run a pair of scissors around. Cutting close to the edge of the pad, Anything left exposed can be poked out of sight.


Lol, a quick explanation grew!

Heres my 580s after modding:


Tights = Stockings btw.

I find the highs bright enough on the HD 650 and sibilant on some stuff, perhaps not as airy as AKG 501 but bright enough. The removal of the foam made no difference to me, in fact I kinda teared the foam from the left cup

I must say, you have great hearing. Consider yourself lucky!! I am 39YO and can still here most high frequencies, but to consider HD650's bright , I wonder what you would say about a Grado!

I also removed the foam and use pieces of fly-screen instead. Two layers for each earcup, but still very thin compared to the normal foam.
This slightly "boosts" the trebles and details (imo).

I'm with fewtch here... modding headphones is bad news!

I'm usually skeptical about upgrading this quote is sooooo true. I just bought an sr-71 and I can't believe how much better my hd-650's sound! I had only listened to amps previously with grado headphones and the difference was only slight. But with 300 ohms the difference is amazing, not just in the highs but in the overall presentation. If I were any of you I would try my damnedest to get to a head fi meet and open that evil box for yourself.

I also am a de-foamer myself by the way. I use a piece of black, sheer fabric that I bought at jo-ann's fabrics for about 99 cents a half yard. I can't remember the type of fabric it was but if you ever see old ladies with that super thin handkerchief over thier hair when its windy thats what it is!

I think it's legitimate to tweak an audio component to your liking. It's not always necessary to exactly know what physically causes the desired effect to make use of it, but it may be useful nonetheless to question it -- since the accumulation of false, impressive short-term effects can lead to a sonic result that will not convince in the long run.

I've tried removing the foam with my HD 580 and my HD 600 -- replacing it with nylon gauze --, and I have become an advocate of this tweak. But after a source change it (the HD 600) sounded better with the foam back in place. There are two factors in play: Sound passing a foam or fabric gets slightly changed and muffled by nature. This effect may be well known from speaker protections. On the other hand there's the beneficial effect from foam and other matters with slight sound-absorbing properties: They can help to reduce reflections on the speaker baffle -- and even from the moved air back to the driver membrane! --, thus make for better sonic contours and transient response.

In the case of headphones said beneficial effect is even more beneficial: The sound waves radiated by the membrane are reflected by the listener's outer ear back to the headphone driver and from there again back to the outer ear, etc. A thin piece of foam makes quite a difference in this scenario. And it's easily audible if you know what to listen for. The higher clarity and brilliance without the dampening foam comes at the price of a tendency to shrillness and softening of the first wavefront with transients, with the result of reduced accuracy and especially reduced depth of image -- everything sounds relatively close, the differentiation between instruments playing further back (thus with a relatively high content of reverberation) and the ones playing in the fore gets somewhat blurred.

That's not the only downside in the case of the HD 580/600/650. If you have a closer look to the innards, you'll notice that the baffle (the surface where the driver is mounted) only consists of a grid covered with fine mesh. It's actually sound permeable, so the design can be seen as totally open, like e.g. the Sony MDR-F1; there's virtually no isolation between front and rear of the driver. This causes the sound waves from both sides, with their opposite phase, to cancel each other -- the further down the frequency range, the more. Of course that's calculated in the over-all design, so don't think the Sennheiser developers don't know what they're doing! But one thing has to be considered: The thin foam pad makes for a slight, but noticeable acoustic isolation between front and rear. So removing it has the consequence of not only increased brilliance, but also decreased bass. Head-fi member j-curve has done some measurements which prove this.

BTW, in my now system -- with HD 650 -- I tried the foam-pad mod several times, but found it to sound worse than the original configuration. I prefer the tightness and control the foam pads provide, as well as the better coherence and spatial reproduction. In the end it's a matter of taste -- and of the own system. Nothing wrong with trying and preferring it -- I'm guilty of this myself.

Yeah, nothing wrong in trying after all. Provided that you put everything back in its proper place soon after having satisfied your insane curiosity. jk


More seriously, I'd agree with the argument expressed by JaZZ. Anyhow, with my modest speaker/headphone "tinkering" experience, I really believe it comes down to problems lying elsewhere than your poor high end headphone (not taking into account hearing problems & such, which would be ).

Look at the difference in sound that using the flat pads and the bowls, make with a Grado. The difference is not subtle, is it grandiose.
Evidently, something as small as moving a thin diffusor screen in front of the 600 family drivers, can change it's characteristics.
But there is always a sacrifice. If it removes the veil, sweetens the highs, but muddles the bass, it's a tough call.
On Grados...the flats bring the drivers closer to your ear, and is great for rock and roll. But the bowls offer a wider soundstage, and is better for jazz and vocals, IMO.
With the Omega II's (which are a wonderful electrostat headphone), the bass is crystal clean but lacks punch. However, if you pull the pads slightly away from your head, the bass on the Stax gets intense. It seems if you break the seal a little the bass improves (the antithesis of most cans). If you rotate the "D" portion of the pads (they are rotatable), the bass increases because there is more padding there, and it provides more distance from your ears, but the soundstage gets kooky.

To each his own.

You see, now I've gone and did it. With all the talk posted on this thread, I decided to put the foam back, just to honestly see if there was no difference, like some say! I learned, that I'm now stuck , with the cans defoamed, because IMHO, it just sounds more crisp, and alive. I thank Vertigo-1, for getting me started on this SHEEAT!

The RS-1 os overall a step brighter but somehow feels good to me. Vocals are sibilant depending on the material. I guess my setup is not very forgiving even with the HD 650. I find the HD 650 highs to be bright (coming from the HD 595) which makes it stand out more compared to the other frequencies.

I just slapped the foams back in place on my 650s...upper bass instantly bloomed and lower bass definition decreased, midrange and treble both become slightly obscured. And annoyingly the tips of my ears touch the foams, and the foams are flattened against the protective driver mesh. But, truth be told, I personally could probably adjust to the sound with or without the foams, now that I'm off the "more details!" horse. I'd defoam them just to stop my ears from touching something more than anything I think.