Are there any dealers that specialize in wind controller gear?
Yes. Patchman Music is a unique dealer that specializes in sales and support of all things relating to the wind controller. If you are in the USA, you can buy a variety of new and used gear from Patchman Music. New Yamaha wind controller gear is available here. New AKAI wind controller systems are available here. New Roland wind controller systems are available here. Patchman Music also maintains a stock of quality used wind controllers and wind controller related accessories and synthesizer modules that work well with a wind controller. Details are here. Patchman Music also repairs wind controllers. and creates sounds specifically designed to be played with a wind controller or breath controller.
