Data from a study of electroencephalographic and behavioural responses to a set of microtonal pitch interval stimuli; together with data on the computational roughness and computational inharmonicity of the stimuli. The data represent the time course of responses at 26 electrodes from a set of musically untrained and musically trained participants. Information on participants' musical sophistication (the OMSI index), and on linking for individual stimuli is included. The stimuli are also classified in music theoretic terms related to theoretical consonance and dissonance. The analytical approaches are discussed in the paper to which they pertain. The authors of the study (conducted at MARCS Institute, University of Western Sydney), are Freya Bailes, Roger T. Dean and Mary Broughton.