The dataset contains 96 multimodal recordings of string quartet performance. Acquired data includes the audio of each performance in separate tracks: up to two ambient tracks and individual tracks acquired through contact microphones. In addition, each recording includes instrumental motion capture and a set of derived instrumental bowing descriptors for each performer, upper body movement for each performer, as well as high-quality video. The recordings were carried out as part of the experiments on ensemble performance inter-dependence reported in the following doctoral dissertation: