I must start this post with a sincere acknowledgment to Kramer. If not for his bold and creative mod, I would not be enjoying my KSC -75s as much as I am now. Thanks very much for pioneering this work, Kramer! And a big thanks to all who contributed to the thread. I have learned quite a bit from many comments and ideas here. And props to tstarn06 for convincing me to give it a go.
I approached my version of the Kramer mod with a few thoughts. I did not want to drill out the center hole for fear that this would add even more treble to a slightly bright overall sound signature. I also wanted to keep the foam intact for now to protect the drivers and to see if it really needed more opening up upon after mod audition. And I wanted to do something to keep the bass sounds focused.
With those thoughts in mid I set out to do the Kramer mod. I used a fellow members guidelines for size of holes starting with four 1/8 in holes around the perimeter and then four 5/32 in holes around the next inner most circle. The 1/8 in holes drilled fine with my regular Black and Decker variable speed drill, but the 5/32 holes did not. They must be drilled with a much slower speed and with a slight angle tipping the drill slightly away from the slanted material and into the side of the surface a bit. If you go directly in vertical and with high speed you may experience some bit slip and then have the entire grill end up twirling up your bit. That caused a problem with extra material being lost instead of a nice hole.
After cleaning up any jagged bits with a razor blade cutting knife, I was on to creating a foam surround donut for the perimeter of the gray housing. I installed the grills back on to the housing and prepped the surround. I used foam Light Switch Sealers that I picked up from Lowes for $1.47 a pack. There are 8 in there and you can get 2 surrounds out of one piece. I chose this because it is fairly dense foam and because it has a lower profile so it will not stretch the foam pads significantly and because it would probably focus the bass a bit more than a more open foam.
I first tried tracing a pattern on paper to use with the foam as a template. Not so good, so I went right to cutting the foam by scoring a line around the housing, being careful to not cut the cord. I thin cut all the way through with the razor knife. Then I took off the grill and pushed it firmly into the foam to make marks. I cut out the center along those marks. I replaced the grill and got ready to mount the surrounds. I am not a good craftsman and my close work is sloppy but I got it done. I used Elmer’s Craft Bond tacky glue which promises to remain flexible should I want to reverse the surround mod, by cutting through it some day. I applied a thin bead around the solid perimeter of the gray housing and carefully positioned the foam on the housing face. I let it dry and then reattached the foam pads. I did not do the Quarter mod to the foam because I wanted to see how the mids improved and how prominent the treble was first.
Upon listening with my Toshiba T-400 later that night, I was very impressed with the results. First the treble was not in your face. It is balanced and smoother with perhaps a bit less air but with a similar sound signature as before. Not as breathy is what I perceive, but that could have more to do with what happened to the mids. The mids are way better. Better definition,, clarity, a bit more immediate and so nicely integrated with the treble that I think they were almost as good as my memories of the AKG K271s. The dynamics of the mid presentation are also much better. The mids just get transformed with this mod.
As for the bass, it has become more easy to hear but not much more defined. It still has limited extension but it has become a bit more focused. It blends nicely with the mids and has not become too bassy. This area is still a bit weak for the KSC -75b, I’m afraid. But overall the mod has elevated the sound to a smooth and fun level. I can think of half a dozen over $50-$150 cans that I would replace with these.
The foam surround have an added benefit of applying more pressure to the ear and coupling the phones more tightly to your ear. While this helps the bass focus, it feels like someone is pinching the ear. It hurts a bit at first but then you get used to it or numb. Have since bent the silver piece outward to relieve the tightness.
A quick note on sources. With the Toshiba, differences between stock and mod are really easy to hear using WMA lossless. With my Creative Zen V Plus the differences are also audible but you really do not hear what the mod can do without a top notch source. I must say the Toshiba trounces the Zen V Plus for sound quality. Now I can see why some folks have commented that some mods are slight if nothing else. Sources matter.
My next steps are to try the quarter mod, but I do not think I will go with a recable. I need to use these when on the treadmill and the weight and flexibility of the cord matter to me. If anyone has any thoughts about the quarter mod and it’s affect alone on the sound of the Kramer mod, I would like to hear those.
I hope this will be helpful to those who have not tried the Kramer mod yet, and inspiring for other great mod ideas to come.
