Acoustic panel for an aircraft propulsion unit, intended to be arranged at the edge of a fluid flow stream of the propulsion unit, the acoustic panel comprising: - a core having an opposing first face and second face, and comprising a plurality of cells designed to form a honeycomb structure, each cell opening onto the first face and the second face; and - an entry layer extending opposite and in contact with the first face of the core, the entry layer comprising a lower element and an upper element, each of the lower and upper elements comprising a plate having an opposing inner face and outer face. the acoustic panel being characterised in that the inner face of each plate is disposed opposite and in contact with the inner face of the other plate, each plate comprises at least one through-hole opening onto the outer face and the inner face of said plate, the inner face of at least one of the plates comprises, for at least one through-hole, a corresponding groove into which the through-hole opens, each groove of a plate is opposite a through-hole of the other plate, in such a way as to form a channel comprising the groove, the through-hole which opens into the groove and the through-hole opposite the groove, for each channel, the through-holes is offset in a direction different from a direction of thickness of the entry layer, the through-hole of the plate of the lower element opening into a cell of the core, and the through-hole of the plate of the upper element being intended to open into the fluid flow stream. the acoustic panel comprising: - a core having an opposing first face and second face, and comprising a plurality of cells designed to form a honeycomb structure, each cell opening onto the first face and the second face; and - an entry layer extending opposite and in contact with the first face of the core, the entry layer comprising a lower element and an upper element, each of the lower and upper elements comprising a plate having an opposing inner face and outer face. - a core having an opposing first face and second face, and comprising a plurality of cells designed to form a honeycomb structure, each cell opening onto the first face and the second face; and - an entry layer extending opposite and in contact with the first face of the core, the entry layer comprising a lower element and an upper element, each of the lower and upper elements comprising a plate having an opposing inner face and outer face. the acoustic panel being characterised in that the inner face of each plate is disposed opposite and in contact with the inner face of the other plate, each plate comprises at least one through-hole opening onto the outer face and the inner face of said plate, the inner face of at least one of the plates comprises, for at least one through-hole, a corresponding groove into which the through-hole opens, each groove of a plate is opposite a through-hole of the other plate, in such a way as to form a channel comprising the groove, the through-hole which opens into the groove and the through-hole opposite the groove, for each channel, the through-holes is offset in a direction different from a direction of thickness of the entry layer, the through-hole of the plate of the lower element opening into a cell of the core, and the through-hole of the plate of the upper element being intended to open into the fluid flow stream.