Panel for the acoustic treatment with a progressive thickness

An aircraft nacelle comprising:

• an air intake (110) with a lip (114) that is extended toward a rear of the air intake (110) by a pipe (116) constructed and arranged to channel an air flow in a direction of a power plant (112), wherein said pipe (116) comprises at least one acoustic treatment panel (120) that comprises, from the outside to the inside:
• an acoustically resistive porous layer (122),
• an alveolar structure (124, 136), wherein all cells of the alveolar structure (124, 136) are of uniform width and are sized for acoustic treatment, and
• a reflective or sound impermeable layer (126), wherein close to an end that is oriented toward the lip (114), said reflective or sound impermeable layer (126) includes an inclined face (130) in such a way as to be connected to the lip (114) and a non-inclined face, the alveolar structure (124, 136) being in contact with both the inclined face (130) and the non-inclined face of the reflective layer, the inclined face (130) forming an angle of less than 30° with a tangent to the acoustically resistive porous layer,
• wherein the acoustically resistive porous layers defines a plurality of pores disposed under both the inclined face (130) and non-inclined face of the reflective or sound impermeable layer (126).