An acoustic structure in which acoustic septa are located in the cells of a honeycomb for reducing the noise generated from a source, said acoustic structure comprising: A) a honeycomb comprising a first edge to be located closest to said source and a second edge, said honeycomb comprising a cell having a left side and a right side, said cell being defined by a lower wall that extends between said first and second edges (14, 16) and an upper wall that also extends between said first and second edges (14, 16), said lower wall comprising a lower left end portion, a lower right end portion and a convex portion located between said lower left and lower right end portions (28, 30), said upper wall comprising an upper left end portion, an upper right end portion and a concave portion located between said upper left and upper right end portions (34, 36), wherein said lower left end portion and said upper left end portion are connected to form a left junction along the left side of said cell and said lower right end portion and said upper right end portion are connected to form a right junction along the right side of said cell; the structure characterised by B) an acoustic septum comprising: a) a planar acoustic portion extending transverse to said upper and lower walls (26, 24), said planar acoustic portion having a top side located nearest to said first edge, a bottom side located nearest to said second edge, a right boundary, a left boundary, a lower boundary and an upper boundary; b) a right tab portion protruding from said acoustic portion at said right boundary; c) a left tab portion protruding from said acoustic portion at said left boundary; d) a lower tab portion protruding from said acoustic portion at said lower boundary; e) an upper tab portion protruding from said acoustic portion at said upper boundary; and C) an adhesive that bonds said right tab portion, left tab portion, lower tab portion and upper tab portion to said honeycomb wherein said right tab portion is bonded to said lower right end portion and said upper right end portion, said left tab portion is bonded to said lower left end portion and said upper left end portion, said lower tab portion is bonded to said convex portion and said upper tab portion is bonded to said concave portion. A) a honeycomb comprising a first edge to be located closest to said source and a second edge, said honeycomb comprising a cell having a left side and a right side, said cell being defined by a lower wall that extends between said first and second edges (14, 16) and an upper wall that also extends between said first and second edges (14, 16), said lower wall comprising a lower left end portion, a lower right end portion and a convex portion located between said lower left and lower right end portions (28, 30), said upper wall comprising an upper left end portion, an upper right end portion and a concave portion located between said upper left and upper right end portions (34, 36), wherein said lower left end portion and said upper left end portion are connected to form a left junction along the left side of said cell and said lower right end portion and said upper right end portion are connected to form a right junction along the right side of said cell; the structure characterised by B) an acoustic septum comprising: a) a planar acoustic portion extending transverse to said upper and lower walls (26, 24), said planar acoustic portion having a top side located nearest to said first edge, a bottom side located nearest to said second edge, a right boundary, a left boundary, a lower boundary and an upper boundary; b) a right tab portion protruding from said acoustic portion at said right boundary; c) a left tab portion protruding from said acoustic portion at said left boundary; d) a lower tab portion protruding from said acoustic portion at said lower boundary; e) an upper tab portion protruding from said acoustic portion at said upper boundary; and a) a planar acoustic portion extending transverse to said upper and lower walls (26, 24), said planar acoustic portion having a top side located nearest to said first edge, a bottom side located nearest to said second edge, a right boundary, a left boundary, a lower boundary and an upper boundary; b) a right tab portion protruding from said acoustic portion at said right boundary; c) a left tab portion protruding from said acoustic portion at said left boundary; d) a lower tab portion protruding from said acoustic portion at said lower boundary; e) an upper tab portion protruding from said acoustic portion at said upper boundary; and C) an adhesive that bonds said right tab portion, left tab portion, lower tab portion and upper tab portion to said honeycomb wherein said right tab portion is bonded to said lower right end portion and said upper right end portion, said left tab portion is bonded to said lower left end portion and said upper left end portion, said lower tab portion is bonded to said convex portion and said upper tab portion is bonded to said concave portion.