The KODA^2 – Optimizing the prototype
Since I made the prototype – I have done some optimizing of the design. It still looks the same on the outsize – but inside has been optimized with the correct sized bass port and 20% less material in overall. This makes them lighter and gives them just the right bass port directly from the laser cutting process. I feel that the weight of the KODA^1 is their only real downside and the new optimized design should issue this and make them below the acceptable 500 grams.  There was so many things that needed a bit of grinding in the prototype on the inside to fit the drivers and it has all been corrected on the KODA^2, making it a better and more polished product while including the almost countless optimizing I did on the prototype J (OK – not countless, but quite a few I assure you).
The background story of the KODA headphones is that I was following the ortho dynamic round-up thread on head-fi.com. That got me interested in making my own custom cans. I knew right away that the T50RP driver was just what I needed for my custom headphone project. A driver capable of delivering an extraordinary detailed midrange – with potential for delivering a fast and tight oomph in the bass region while maintaining detailed highs, without emphasizing them too much. This was why I made the KODA headphones and you can read about that project here: http://diy.koenigs.dk/2014/02/22/koda1-koenigs-ortho-dynamic-acrylic-headphone/Â
The changes from KODA^1 to KODA^2
- Nicer veneer – I will let you choose between a couple of types like walnut burr or zebrano
- Nice thick black felt on the inside of the headband – very discrete
- Minor tweaks and optimization to the inside dampening
- Bass port micro-tuned for even bette balance
- Less reflective, matte finish on earside of baffle
- About 20% lighter
- Reflective felt spot behind on back of cup
I got all the parts and I have started making the first 4 units. I’m using a wood board with nails to control the pieces and to make sure they are perfectly aligned. This is only two units on this picture though.
Three types of very fine veneer – not even varnished yet, but they are sanded with 400 grit. My favorite is the Macasser Ebony farthest to the right. The other veneers are Walnut burr and Australian Walnut.
New and very improved baffle, unbelievable stiff and it’s matte polished to be less reflective and have a nicer feel.
Australien Walnut – first finished cups.
Matte polished with veneer almost completely polished away for a burned look. Then it is treated with bee wax. The polishing of the parts is a tiresome process and I have used almost 6 hours doing so.  But I think this is becoming my favorite look. I really love the look of the matte polished acrylics with bee wax. It feels fantastic too.
Much smaller ball joints – I had to do some drilling to get the aluminium rods to fit. The result is a much lower weight and nicer and more balanced look, than on the KODA^1
Baffles with the T50rp planar magnetic / ortho dynamic drivers and flet hole damping. Notice the silicone gaskets for air tightness.
The last cups is finished – It’s the second from left, ebony.
Internal dampening felt. The nuts will be covered with a reflex dot made in hard felt.
Reflex dots. The felt with hole over the driver makes sure the bass is deep and the reflex dot lifts the treble a notch.
My hearing says it’s working beautifully.
Closing the first cup – embedded screws and matte rough surface.
Finally the first finished KODA^2 – IMHO it’s much nicer looking than the prototype and almost 100 grams lighter.
Very nice wiring, Neutrik plug and they are so comfortable.
Ear side of cup (Australian walnut veneer cans)
Some shots of the finished unit:  MACASSAR EBONY + Bee Wax  -  KODA^2
Matte polished acrylic with walnut burr and bee wax  -  my own headphones
Finally for some measurements, done after a lot of fine tuning. The light grey line is the KODA^2 before I got my test bench made and unfortunately it also the pair of headphones that was used for review.
