Various studies have shown that haptic interfaces could enhance the learning efficiency in music learning, but most existing studies focus on training motor skills of instrument playing such as finger motions. In this paper, we present a wearable haptic device to guide diaphragmatic breathing, which can be used in vocal training as well as the learning of wind instruments. The device is a wearable strap vest, consisting of a spinal exoskeleton on the back for inhalation and an elastic belt around the waist for exhalation. We first conducted case studies to assess how convenient and comfortable to wear the device, and then evaluate its effectiveness in guiding rhythm and breath.Results show users' acceptance of the haptic interface and the potential of haptic guidance in vocal training.

Breath is a significant component in singing performance, which is still underresearched in most singing-related music interfaces. In this paper, we present a multimodal system that detects the learner's singing pitch and breathing states and provides real-time visual tutoring feedback. Specifically, the breath detector is a wearable belt with pressure sensors and flexible fabric. It monitors real-time body movement of the abdomen, back waist, and twin ribs. A breath visualization algorithm is developed to display real-time breath states, together with the singing pitch contours on an interactive score interface. User studies show that our system can help users not only gain deeper breath during singing but also improve pitch accuracy in vocal training, especially for those with some musical background.