OB-Xd is based on the Oberheim OB-X. It attempts to recreate its sound and behavior, but as the original was very limited in some important ways, a number of things were added or altered to the original design.
OB-Xd was designed to sound as good and as rich as the original. It implements micro random detuning. Also, like many synths of the OB-X's generation, the OB-Xd has no internal effects so its sounds and textures can be greatly enhanced by the use of additional processing like chorus, reverb, delay, etc.
Resolved an issue where the Bend Octave button MIDI CC was being overlapped by another parameter. This has been rectified by reassigning the MIDI CC to number 32.
Scope AUv3 Visualizer 
Schroeder AUv3 Reverb 
OPL AUv3 FM Synth 