[EN] This Letter presents practical realization of a two-dimensional low loss acoustic cloak for airborne sound obtained by inverse design. The cloak consists of 120 aluminum cylinders of 15 mm diameter surrounding the cloaked object¿a cylinder of diameter 22.5 cm. The position of each cylinder in the cloak is optimized using the data from two different techniques: genetic algorithm and simulated annealing. The operation frequency of this cloak is 3061 Hz with the bandwidth of about 100 Hz. Being a multi-step approach to the desired cloaking, the inverse design is also valid, in principle, for non-symmetric cylinders and even for three-dimensional objects. VC 2011 American Institute of Physics ; ONR N000140910554 ; Spanish MCINN TEC2010-19751 ; Spanish MCINN TEC2008-06756-C03-03 ; Spanish MCINN CSD2008-00066 ; CSIC JAEDoc-08-00351 ; Garcia Chocano, VM.; Diaz Rubio, A.; Cervera Moreno, FS.; Sánchez-dehesa Moreno-cid, J.; Sanchis, L.; Martínez Pastor, JP.; Llopis Pontiveros, R. (2011). Acoustic cloack for airborne sound by inverse design. APPLIED PHYSICS LETTERS. 99(7):74102-74102. doi:10.1063/1.3623761. ; Senia ; 74102 ; 74102 ; 99 ; 7