A gas turbomachinery comprising: an air supply unit, having a first end and a second end, wherein the second end is capable of releasing a volume of air to a blower; the blower, having a first end and a second end, wherein the first end is capable of receiving the volume of air from the air supply unit; and a silencing unit (12, 20; 40), comprising a first aperture (24; 44) and a second aperture (26; 46) connected via an air flow duct, the silencing unit (12, 20; 40) placed between the air supply unit and the blower, the air flow duct comprising two layers of acoustic absorbing material (31; 51); wherein the first aperture (24; 44) of the silencing unit (12; 20; 40) is adapted to receive a volume of air released from the air supply unit which is positioned in proximity of the silencing unit (12; 20; 40), and the second aperture (26; 46) of the silencing unit (12; 20; 40) is adapted to release the volume of air and to direct the volume of air to the blower characterized in that: the blower is positioned in proximity to the silencing unit (12; 20; 40), wherein the first aperture (24; 44) of the silencing unit (12; 20; 40) is bigger than the second aperture (26; 46); and in that the two layers of acoustic absorbing material (31; 51) are arranged in two concentric layers (28, 30; 47, 48) from the centre of the air flow duct, wherein a clearance (34; 55) is arranged between the two concentric layers (28, 30; 47, 48). an air supply unit, having a first end and a second end, wherein the second end is capable of releasing a volume of air to a blower; the blower, having a first end and a second end, wherein the first end is capable of receiving the volume of air from the air supply unit; and a silencing unit (12, 20; 40), comprising a first aperture (24; 44) and a second aperture (26; 46) connected via an air flow duct, the silencing unit (12, 20; 40) placed between the air supply unit and the blower, the air flow duct comprising two layers of acoustic absorbing material (31; 51); wherein the first aperture (24; 44) of the silencing unit (12; 20; 40) is adapted to receive a volume of air released from the air supply unit which is positioned in proximity of the silencing unit (12; 20; 40), and the second aperture (26; 46) of the silencing unit (12; 20; 40) is adapted to release the volume of air and to direct the volume of air to the blower characterized in that: the blower is positioned in proximity to the silencing unit (12; 20; 40), wherein the first aperture (24; 44) of the silencing unit (12; 20; 40) is bigger than the second aperture (26; 46); and in that the two layers of acoustic absorbing material (31; 51) are arranged in two concentric layers (28, 30; 47, 48) from the centre of the air flow duct, wherein a clearance (34; 55) is arranged between the two concentric layers (28, 30; 47, 48). the blower is positioned in proximity to the silencing unit (12; 20; 40), wherein the first aperture (24; 44) of the silencing unit (12; 20; 40) is bigger than the second aperture (26; 46); and in that the two layers of acoustic absorbing material (31; 51) are arranged in two concentric layers (28, 30; 47, 48) from the centre of the air flow duct, wherein a clearance (34; 55) is arranged between the two concentric layers (28, 30; 47, 48).