This book contains the complete MSc research that has been carried out to gain insight in the possible improvements of sound insulation of membrane structures, from a state-of-the-art review to practical solutions. Membrane structures are used in temporary structures, e.g. festival tents, or other structural solutions. Three different kind of filling materials were used in the present study: (lightweight) glass wool, polyester wool and aerogel. Acoustical measurements were carried out in a laboratory, of which the outcomes were compared to a number of computer and mathematical models. A well performing triple-layer membrane system is discussed, which met the restriction of 7kg/m2 for the surface density of the membrane package. This system includes one layer of aerogel for reasonable sound insulation at low frequencies, and one thicker layer of glass wool yielding good sound insulation at higher frequencies. Furthermore, details have been worked out at the end of the book for a number of practical membrane structure applications using this result, focussing on tent structures.