Koss UR-55 Soundstage and Grill MOD
Jan 18, 2011 at 4:01 PM Post #16 of 41
OK, done the mod, there is a slight difference, removing the fabric between the metal grill and the housing takes off some of the boxiness and extends the soundstage, but for me these differences were very subtle, but then my ur55's have only got about 40 odd hours on them, so maybe they will open up  bit more with time.
 
Mar 18, 2011 at 8:55 AM Post #17 of 41


Quote:
It's OK, I've worked it out, the foam pads are mounted onto a thin plastic base, that is then glued onto the main housing, you place the screwdriver between the plastic base of the foam and the housing, then lift up, I'll post some pics in a bit.


Could you please post the pics as promised? Thanks! :)
 
 
Mar 18, 2011 at 10:57 AM Post #18 of 41
I'm using the screwdriver in between the plastic base and the rest of the plastic housing part but working around with it lifts the base only so much. It just won't come off and I'm afraid I might break what seems like plastic latches extending from the housing to the base (one of these latches is seen in the pic, it's the shiny part to the left of where my screwdriver is stuck):
 

 
Mar 21, 2011 at 3:48 AM Post #19 of 41
Anyone?
 
Mar 23, 2011 at 9:36 AM Post #20 of 41
Is this mod officially dead now? :)
 
Apr 2, 2011 at 5:56 PM Post #21 of 41
Sorry globalist, I've got the pictures and will post when I get the usb cable for my blackberry from my PC at work...
 
I did the exact same thing as you at first, but don't pry up the plastic casing, this will break the phones, basically the pads are glued on to the housing if you run your finger nail under the foam pads you will find a very thin plastic base that the foam is attached to, this needs to be lifed up and gently removed.
 
The foam is actually pretty robust, but use a bit of care when lifting up from the housing.
 
Since posting the extra bits to Travis' original post, I have worked out another huge enhancement to greatly improve the top end resolution.
 
This involves some felt and sticky back foam (from hobbycraft - total cost about £1.50).
 
I'll post very soon in the DIY section.
 
Apr 3, 2011 at 1:23 AM Post #23 of 41
Sorry for not replying to all these comments. I should have subscribed to my own thread and I often don't visit the portable section much.
 
Yeah the plastic is behind the foam and the foam pad will re-attach when removed. Just be careful to not rip the foam.
 
Once the foam is off there are screws below it. I should have posted pictures when I did this mod!
 
I bet with mods this headphone can be improved even more! I want to figure out how to add even better clarity to it's sound.
Maybe removing the felt from the driver would help, but I haven't tried it yet.
 
I don't suggest this mod on new pairs, since it can be a risk if you don't like the results.
 
BTW Koss now sells a closed version called the UR-50. Not sure how much different the sound is.
 
I bet it could be modded with some blu-tack or something. I have to say that I'm not a fan of the UR-55's foam pads.
 
Apr 3, 2011 at 8:05 AM Post #24 of 41
OK, to improve the top end and upper mid range of the phones, you will need to remove the ear pads as shown above, and stick on some adhesive foam (2mm thick), and a layer of self adhesive felt (same depth), the pictures below show how this can be acheived.
 
The felt reduces the seal of the ear pads and lets some air get between the housing and the base of the ear pads, onve the felt and foam are in place, the ear pads can be re-attached using double sided sticky tape.
 
The results push the sound quality of the UR 55's well above the Grado SR-60's (I compared A-B), and remove the recessed top end of the UR 55's (this looks to have been caused by the tight seal of the ear cups to improve isolation by Koss):
 

 
Add the felt to the front of the housing so it is facing forward with the phones on your head.
 

 
Once the felt (the darker more matt stuff above), is in place, glue the ear pads back on with double sided sticky tape and enjoy.
 

 
The top end can be increased or reduced depending on the ratio of foam and felt (by reducing or increasing either way).
 
Good luck!
 
Jan 28, 2013 at 8:30 PM Post #26 of 41
just bought these for 40$, sound is good, but not as amazing as i read they were. Comfort is also an issue.
 
Very interested in performing this mod, but have no idea how, can someone explain step by step, or maybe post a video...
 
Dont want to ruin them since they are still new.
 
Aug 14, 2013 at 8:49 PM Post #27 of 41
I know that I am reviving this dead topic, but these headphones are so good that I had to create an account to show my appreciation. I have been using the grado sr60 extensively for about a year. I love the smooth treble (I find that other headphones have sparkly/sibilant treble which irritates me) on the Grado, the forward vocals and airy sound. However, I really hate the gargantuan cable with a passion. I was searching a while for a more portable headphone with a similar sound signature with no success...until now.
 
The Koss UR55 sound like your typical bassy, muddy, boxy, muffled headphones you get for 50$ or less out of the box. I find the comfort pretty good for cheap cans though. I am used to having maximum clamping force on my head with headphones such as the Audio Technica ES7, the Incipio f38 or the JVC S400. Koss could do a lot worse. Anyway, I did the mod successfully. the pads peeled off nicely using my nails. However, the cheap screws proved to be a challenge once I had to put the headphones back together. 
 
About the sound:
 
- I really love the treble. It's smooth, maybe rolled off but that's what I want.
- The vocals are forward, the distorted guitars sound amazing. It's very "in your face" like a Grado.
- The bass is there, but it's shy. I like that extra kick in the drums feel, and it's not really there. I am sad to say that the Grado sr60 has more bass. 
- The soundstage is very impressive. I can't think of any sub 100$ headphone with better soundstage.
- Overall, I am blown away for 29$. The Grado sr60 looks really over-hyped and over-priced right now.  
 
There is one problem though: How can you recommend people this headphone if you have to tell them to take it apart? 
 
Nov 22, 2013 at 2:20 PM Post #29 of 41
Well, it's more like a fine layer of felt paper that lies right beneath the grille. It is far from the driver so there is no damaging risks. Unfortunately, it's glued on this plastic structure so you will have to tear it off.
 
On a side note, I just got the Koss KSC75 (as the headband on the UR55 was a tad too small, and the foam earpads were so uncomfortable).
 
Well I have to say that the sound is nearly identical to the modded UR55, but with less bass and grainier treble. This is a trade-off I am glad to accept as the price is much lower and the comfort is so much better.
 
And I have to mention that I used the KSC75 straight out of the box. 
 
Jan 5, 2015 at 5:51 PM Post #30 of 41
got a pair, doing a lot of experiments and taking lots of (subpar) photos.
 
my pads came off really clean

 
i used a dull knife and stuck it under the plastic film that the foam is attached to. its easy to slip it under there if you don't start at a sharp angle, find the edge of the plastic and start putting pressure and a 90 degree angle (perpendicular from the driver) then do sort of a prying motion.
 
grills can't be reused? that sounds like a challenge
 

 

 
the trick is to pry up the tabs and get them at the right angle and then push out them out from the inside, going back and forth between the tabs until you've pushed out the entire grill. don't even touch the outside of the grill until you can't push the tabs out anymore. you should be able to get one side off, then you can GENTLY grip the sides of the grill and wiggle it around, pulling the remaining 2 tabs STRAIGHT off, don't do any prying or any of that.
 

 
when you put the grill back on, you have to stick the tabs back in the order that they were removed. if you get one side off first then the tabs on the other side will be bent outward a little more so they need to go in first
 
at least on mine, the fabric isn't actually glued down everywhere, so it wasn't too bad to remove it.
 

 

 

 
scraping away the excess with a knife. better to use a sharp razor blade, i took some of the plastic with it. other methods i considered:
lighting it on fire
using my safety razor and shaving it like i would shave my face
using adhesive remover (probably the cleanest option)
 
anyway it wasn't a big deal, came off pretty clean
 

 
i put the grills back on and listened with and without the grills (after removing the fabric) and didn't notice any difference.
 
next i wanted to try improving the low end a little
 

 
does anyone know what this little sticker over the back of the driver is?? i removed it, though i guess i shouldn't have. it didn't seem to make much of a difference. it occurred to me that it might be there to seal out dust or something.
next i did one of the common grado basshead mods:
 

 
HOLY HERTZ BATMAN
THIS IS LIKE A VIBRATING BRAIN MASSAGER
 
....seriously its WAY too much bass, seems pretty distorted. i wish i had a better ear, i produce but i don't know a lot about mixing. anyone have a guide on improving your ear for mixing/audiophile purposes? i've been listening some bjork off volta and homogenic and some of aphex twins new album as well as young montana. the treble actually seems a bit tinny to me and the high mids seem a little muffled.
anyway i want to try the felt/foam mod because my grados still have more clarity in the treble and soundstage for sure. i'm thinking maybe it will make the bass less distorted as it will reduce the seal around the pads/ears. i seem to remember some grado modders doing the opposite and increasing the bass by wrapping tape around the circumference of the pads to increase the seal. much more experimentation ahead.
 

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