The Spin Doctor has been around for quite some time now. It offers 16 rotary controllers, which can be assigned in 25 different programs. The unit must be powered from an external power source as it only has MIDI connectivity, though it is capable of merging an incoming MIDI signal with the outgoing signal (this contains the MIDI events produced by the unit). The Spin Doctor can also serve as a MIDI Analyser, making it a potentially useful problem-solving tool to have in your studio.
The basic four-digit LED display shows the control value that´s being transmitted. It´s also used to demonstrate the functionality offered by the current preset -- a brief description scrolls across the display.
The Spin Doctor is supported natively in Reason, and as with many control surfaces, the knobs available are effectively multiplied through the use of keyboard shortcuts. This means that practically the entire Reason mixer can be controlled using just the 16 rotaries.
A simple PC-based utility can be used to edit, load and save templates to and from the control surface -- useful if you find editing on the device to be a bit convoluted. The Spin Doctor has an all-metal case and is built like a tank. In terms of value for money, it compares well with the Evolution X-Session, but unfortunately lacks the convenience and ease of use of a USB connection.