The cobla according to the gramophone; The interpretation of sardanes between 1920 and 1950 is a PHD that emerged from the interest in the historical recovery of cobla music of the first half of twentieth century. The study is based on auditory observation that, in the future, can be applied and used to recover any kind of interpretative practice that has been recorded in a sound document –beyond of music for cobla-. The PHD raises the following hypotheses: • All the cobles of the second quarter of the twentieth century played the same types of repertoire but not all used the same criteria when performing it. • There were cobles who specialized in a type of sardana or another and there was a difference between what is called to play in Girona’s or Barcelona’s stlye. • Also, in that period (1920-1950), the distinction between what nowadays is called sardanes to dance or sardanes for concert was produced. • The cobles played differently depending on whether the sardana was more or less danceable. • Throught the period studied there was a progresive homogenization of compositional and interpretative styles. • The state of conservation and precision in the documentation of the sources is relevant to obtain reliable observation and analysis results. The results of this thesis confirm the hypotheses raised and they show that digitization, understood as the production and conservation of a singular recording reproduction, that can be more or less manipulated (with criteria that can be described or not) so that the results of the analyzes are always subjected to these considerations. In summary, the thesis states that from the year 1920 to the year 1930 most of the recordings we have documented were produced. It is also noted that the most recorded authors were Vicenç Bou, Enric Morera, Pep Ventura, Josep Maria Tarridas, Joaquim Serra, Juli Garreta and Josep Vicens. Bou, Tarridas and Vicens were considered the main authors of sardanes to dance while Morera, Serra and Garreta were considered the greatest exponents of sardanes of concert. The thesis shows that each cobla had its own interpretative criteria, but with slight variations depending on the style of the composition; and this unique interpretative criteria of each cobla used to go together with the compositional style of some authors or others and this caused that the cobles had, each one, a certain degree of specialization when playing more danceable or concert sardanes. It was during the twenties that the difference between dance and concert sardanes was consolidated, and probably the interpretative differences between cobles such as Montgrins and Barcelona helped this division. In a way, even today, some of the most popular interpretative practices known as “tocar de Girona” and other more elitist are currently identified with academicism known as “tocar de Barcelona”. However, the analytical study of the recordings also shows that over the years studied there was a progresive process of homogeneization in the way of performing sardanes, which has led to the way of performing sardanes nowadays.