An experimental system for studying acoustic signals generated by a modulated MeV ion beam in metals is described. For detection, a closed cell on the rear side of a copper or aluminum sample, a half‐inch condenser microphone, and a lock‐in amplifier were employed. The pressure signal was found to be proportional to beam current and particle energy, and inversely proportional to cell length. Decrease of the signal magnitude and increase of the phase delay with increasing modulation frequency and sample thickness were also observed.