Fostex Orthodynamic Line Overview
The Fostex Company was founded in July 1973 by Foster Electric Co., Ltd. (founded 1949). Fostex was established to brand high quality speaker components from Foster and sell them direct to consumers and dealers in the Japanese marketplace. As to be expected of a division of Foster Electric Co., Ltd., Fostex also produces a range of microphones, headphones, studio monitors and portable PA speakers.
Orthodynamic Headphone Line History
Fostex started making orthodynamic headphones in the mid 70's and continues to manufacture them to this date under the RP (Regular Phase, or as Fostex now calls it, Regulated Phase) moniker. Fostex describes the technology this way:
Key to the transparent sound reproduction is Fostex's RP Technology, a proprietary transducer and diaphragm design that has earned Fostex more than twenty international patents and has been successfully applied to microphones, headphones and loudspeakers used and relied upon in professional and commercial sound installations worldwide.
There have now been three generations of RP headphones. With each, the sound signature has moved farther away from audiophile to one tailored to the specific needs of studio professionals. Which is not to say that the sound of the latest generation can't be wrestled back into the audiophile realm-- it will simply take a lot of work and expense.
Fostex Orthodynamic Line Models of Interest
Fostex T50 v2 & OEM headphones
As you might have noticed the names of the models were reused over the years and sometimes the same name was used for two completely different headphones. Wualta created a simple guide in the orthodynamic thread, here is the link to the wiki article with this Fostex orthodynamic headphone identification guide.
In addition to the models listed above there were several probable Fostex OEM headphones:
Brochures and Various Pictures
Current Fostex RP lineup
Fostex 1986 RP lineup
Fostex 1980 RP lineup
Fostex 1978 RP lineup