Ocharaku are a little-known Tokyo-based earphone maker. Their claim to fame is the proprietary Twin Equalised Element technology (TEE). TEE places two drivers of the exact same spec in a single sound chamber. In order to reduce unwanted resonance, the drivers fire in different directions and a 'phase correction tube' ensures equal sound pressure is delivered to the ear.
Recently, the Flat4 was updated with a maple sound chamber. It has been crafted by master craftsman, Takayama Hida.
The Flat4-SUI is finished in aluminium, KAEDE in maple. KAEDE costs 71.400¥; SUI costs 33.000¥, taxes included. Obviously, these are premium products meant for discerning audiophiles.
Ocharaku earphones are designed by ex-Sony earphone/speaker designer, Mr. Yamagishi, and as such employ cutting-edge technology. At their prices, and considering that each one is completely hand-made, a typical run of Ocharaku earphones is about 200. Once sold out, another run may not be made. This is especially true with the KAEDE. Ocharaku are exceedingly careful with the materials they use. Curing, laminating, and carving another maple tree may not result in the same sound as a different production line.
NOTE: ohm-image did not take the wonderful images seen on Ocharaku's webpage.
Details in Japanese and English are listed at Ocharaku's Flat4 product page.