The sound of pitched orchestral instruments consists of harmonic frequencies which, in performances, are transmitted over room acoustics. The amplitude relations of the harmonic peaks affect the timbre of one tone. When two or more notes are played together, the effect of consonance and dissonance becomes prominent. The degree of consonance for intervals of musical pitches have been explained by the frequency separation of their harmonic components in relation to the width of critical bands in human hearing. When the playing dynamics is varied, the changes in the instruments’ spectral envelopes are foreseen to alter also the consonance of simultaneous notes. Furthermore, the room acoustics influence the overall harmonic spectra conveyed to the listeners. This paper presents experiments on the tonal consonance of orchestra instruments at contrasting dynamic levels in various concert halls. By combining binaural hall measurements and anechoic instrument recordings with a consonance-estimating model, the following hypothesis is investigated: do the acoustics of concert halls change the orchestra sound’s consonance in different music dynamics?