Noise attenuating device in order to equip the end of an air conduit with a gas stream running through it, wherein the device comprises: - a deflector , which is suitable to intersect the axis (xx) of the stream at the end of the conduit , - wherein the deflector is formed from: * resonator cavities , which are provided with necks , * wherein these cavities are covered with a layer of absorbent foam , and * wherein the necks of the cavities traverse the layer of absorbent foam , wherein the noise attenuating device comprises an open body , which is provided with a connector for the conduit and with an inlet/outlet opening , characterized in that the body is provided with a cut-out at the point of intersection of the stream out of the conduit and into the opening , wherein this cut-out is closed by a cover which is combined with the body in order to form the deflector, by including: - a frame (3, 3a, which is provided with partitions and is fixed in the cover and which, together with the cover , delimits resonator cavities , with: * a sheet which carries tubular elements which form the necks of the resonator cavities , * wherein the sheet is covered by a layer of absorbent foam and is traversed by the tubular elements . - a deflector , which is suitable to intersect the axis (xx) of the stream at the end of the conduit , - wherein the deflector is formed from: * resonator cavities , which are provided with necks , * wherein these cavities are covered with a layer of absorbent foam , and * wherein the necks of the cavities traverse the layer of absorbent foam , wherein the noise attenuating device comprises an open body , which is provided with a connector for the conduit and with an inlet/outlet opening , characterized in that the body is provided with a cut-out at the point of intersection of the stream out of the conduit and into the opening , wherein this cut-out is closed by a cover which is combined with the body in order to form the deflector, by including: - a frame (3, 3a, which is provided with partitions and is fixed in the cover and which, together with the cover , delimits resonator cavities , with: * a sheet which carries tubular elements which form the necks of the resonator cavities , * wherein the sheet is covered by a layer of absorbent foam and is traversed by the tubular elements . * resonator cavities , which are provided with necks , * wherein these cavities are covered with a layer of absorbent foam , and * wherein the necks of the cavities traverse the layer of absorbent foam , wherein the noise attenuating device comprises an open body , which is provided with a connector for the conduit and with an inlet/outlet opening , characterized in that the body is provided with a cut-out at the point of intersection of the stream out of the conduit and into the opening , wherein this cut-out is closed by a cover which is combined with the body in order to form the deflector, by including: - a frame (3, 3a, which is provided with partitions and is fixed in the cover and which, together with the cover , delimits resonator cavities , with: - a frame (3, 3a, which is provided with partitions and is fixed in the cover and which, together with the cover , delimits resonator cavities , with: * a sheet which carries tubular elements which form the necks of the resonator cavities , * wherein the sheet is covered by a layer of absorbent foam and is traversed by the tubular elements . <EOS>