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. <EOS>