Oberheim Electronics Inc.
The "OB-X" is the first model from the "OB series". It was sold with 4, 6 or 8 voices (in this concert the 8-voice-version was used, that's why "OB-X 8 voice"). It was a little overshadowed by the bigger OB-Xa and OB-8 later.
Usage in Kitaro's music:
This instrument was used in the concert In Person Digital. It wasn't played by Kitaro, but Ryo Okumoto. If it was used on other studio recordings from Kitaro is not known.
To hear on which album or to see on which DVD?