Pianists often use asynchrony with the purpose of making multiple voices more transparent or providing extra emphasis at particular locations. This study evaluates the perceptual effects of such asynchronies in performances of three pieces with varying textures: a Bach Fugue, a Brahms Intermezzo and a Chopin Prelude. By varying onset times (+55ms, 0, -55ms) and key velocity values (0, +10 units) of the bass and melody voices of a pre-recorded professional performance on a Yamaha Disklavier, 11 different performances were synthesised. 21 participants were presented these performances in random order and asked three questions in consecutive sessions: How rich is the timbre? How transparent are the different voices? How expressive do you think this performance is and is it appropriate for the piece? Strong agreement is found for ratings of richness and transparency, but few significant differences appear between different levels of asynchrony and key velocity. ANOVAs reveal effects of asynchrony in Bach, and pianists differ from non-pianists in their ratings of transparency and expressiveness for Chopin and Brahms.