[bashot]

The Kramer mod is very good. Drilling holes in the grill really does improve the SQ. They sound great in fact, but they still have a bit of a 'canned' sound - the mids are recessed and a bit 'honky', the bass is unrefined, and the highs can sound tinny. In short, they still have many defects that closed cans have. You can't remove the plastic backing because its fused to the coil.

So I drilled out the backing. Aesthetically, this first attempt is far from perfect:

I first started with the slots rather than the tiny holes. YOU CANNOT DRILL OUT THE SLOTS! Beneath them is a hard plastic frame that stabilizes the driver to the plastic shell. It extends far down, very very close to the back of the membrane. But under the tiny holes there's plenty of space:

The second cup I did looks much better:

I used a 11/64" drill bit because my tools aren't well organized and I tried to grab a 3/16". Both would work well. Drilling at slow speeds works best so dremels might be too fast for this unless you have very sensitive hands. I say sensitive because you can tell when you've drilled far enough by feel. I firmly stabilized the cups on a table top with my left hand and applied low/moderate pressure with the drill while drilling. The bit was perpendicular to the curvature of the cup, not straight down, and placed in the middle hole to start. When the tip of the bit punctures through the plastic there's a sudden increase in friction on the bit, which I felt as a sharp increase in the torque on the cup. This increase is due to the fact that the angled tip of the drill bit is no longer in contact with the plastic but the sides of the bit are: more surface area = more friction = more torque. A couple small flakes of plastic made their way into the cup but these were easily blown out from the side once all the holes were done.

Oh yeah. The sound. I wouldn't be posting this if I damaged the membranes and they are indeed fully intact

. The added holes do help alleviate the closed sound of the KSC75 but not fully. Although its not hugely dramatic, the low are crisper, instrument separation is improved and the mids are more in the foreground to me.

My apologies for not giving credit to anyone who has done this before. I searched but didn't find anything.

 

[Lad27]

Good idea. I'll give it try on mine 75's. Looking at the pics, holes could be of even larger diameter. Is that right?

Cheers

 

[GreatDane]

Great idea. I'd like to hear this.

...I knew I should've bought 3 pairs at Radio Shack for $35 a few weeks ago. D'OH.

 

[eruditass]

interesting, i wholely agree about the mids and highs. i havnt done the kramer because i fear more tinny treble.

 

[veryfaststuff]

Pardon me for gravedigging, but I would like to make a caveat--I made a mistake and badly pierced a driver. When you drill a hole into the exterior, make sure you're using a bit with a relatively shallow/flat tip*; pressure in the center would create an uneven distribution. Otherwise, you risk the chance of build-up plastic around the interior of the hole that would push/pierce the membrane; even if not so, the build-up would be tedious, if not difficult to remove.

*That said, I cannot guarantee drilling the phones for relatively marginal improvement. Additionally, a shallow/flat tip might not even make a difference for those without the proper technique. I'd recommend drilling a plane of plastic to make sure there is no excess dipping that results on the opposite side.

 

[eruditass]

interesting, i forgot about this, has anyone else tried it?

i'm still experimenting with different combination hoes in the kramer mod.

im scared of leaving plastic at the back of the driver

 

[PhoxHound]

Anyone tried doing both on one set? wonder how that would sound...

 

[i_don't_know]

What if you were to completely drill an open space between each of the slots? Wouldn't that technically open them up even more, and possibly make an even more significant difference? I'm sure there must be a tool that could scrape the edges of the drilled holes out further to do this. Of course it would look disgusting, and might even need some sort of mesh or something stretched over it to keep random objects from entering your headphones, but I think it's worth trying.

EDIT: By the way, I don't know anything about this. I'm just expanding on your idea.

 

[buffpants24]

any update on this mod? i just picked up a couple of these from radioshack and i'm thinking about modding one of them.

 

[GreatDane]

Quote:

Originally Posted by buffpants24 /img/forum/go_quote.gif any update on this mod? i just picked up a couple of these from radioshack and i'm thinking about modding one of them.

Thanks for bumping this. I totally forgot about trying this. I might do this over the weekend.

 

[havieri23]

aww man i knew i shouldn't do this mod. i was fine with the kramer mod, but i kept on going. when i did this, i accidently drilled and broke the rear mesh and one side (i didn't hit the driver) but now my 75 is crackling on one side (it takes alot of concentration and a sharp drill bit). what a waste, and i was looking forward to the lifetime warranty. luckily i got a second pair. i'm going to leave it alone.

 

[Leonchan]

I didn't have access have a drill so I the next best thing I could, and highly effective too! Oh my god, it sounds much better now. It's no longer tinny. Tremble, and mids are more refined. It does help alleviate the closed sound indeed. Sorry about the pics. I used my blackberry.

It's fairly simple to do. Use something that can go into those holes, and strong enough to scoop the extra stuff in between out.

No damage what so ever. 13 slots instead of 7. Much less resonances