## 1 Introduction  
At present, the need of sustainable buildings is rising all over Europe and thus their construction is growing quickly [1]. Therefore, high-rise wooden edifices are more and more requested in the market [2, 3, 4]. These edifices are composed using different elements. Often, timber frame is used for the construction of walls [5, 6] and Cross Laminated Timber (CLT) for floors [7, 8]. In this light, CLT horizontal partitions have to fulfil many requisites like structural integrity etc., but recently sound insulation and impact noise reduction as well as indoor acoustic comfort are becoming important issues to manage. Anyway, bare horizontal partitions do not easily fulfill acoustic law requirements [9] and thus many other layers have to be added. In order to solve these problems, many works were developed in years to study the acoustic behavior of this type of timber element. In a recent review, [PERSON] and [PERSON] [10] focused on bare structures elucidating their properties and construction phases. Such structures have several advantages:  
(1) eco-sustainability;  
(2) anti-seismicity;  
(3) thermally insulating;  
(4) possibility of dry construction;  
(5) possibility of raising existing structures thanks to the reduced weight. When focusing on layered CLT elements, [PERSON] and [PERSON] [11] presented a dedicated study using laboratory and field measurements of sound insulation and impact noise reduction of some CLT components. Anyway, no parametric study related to the influence of the single layer is included. The same consideration could be applied to many other works [12; 13; 14; 15]. Due to the reduced weight of CLT elements, their poor acoustic performances could lead to problems in the lower frequency range when in presence of impact noises such as children or adults walking or running. In order to reduce impact noise or to increase sound insulation, some other technologies have to be coupled to the bare timber floor. Two of the most used are (i) floating floor and (ii) suspended ceiling. [PERSON] et al. [16] found that a floating floor addition using resilient materials ensures good performance against lightweight impact noise, but has rather negative effects due to the resonance on the heavy weight impact noise caused by the falling of heavy objects or children walking/running. It is thus evident how there is a lack of parametric studies, discussing the influence of single noise reduction action on CLT floors and, in addition, their overall contribution when laid together on the same horizontal partition. Furthermore, there is a lack of studies comprising different acoustic excitation techniques on such floors [17], providing single configuration influence on final sound reduction. Timber constructions are relatively new in the European market. People usually live in traditional heavyweight ones made of masonry and/or concrete. When moving on new sustainable edifices, people feel new indoor environment and new noises, which were not present in traditional houses. Thus, subjective evaluations are now part of the research order to understand if timber buildings could provide a suitable environment from the point of view of acoustic comfort [18]. In this view, the rubber impact ball was demonstrated to be the noise source most associated with subjective reactions [19; 20]. However, to the authors' knowledge, no parametric research comparing the influence of noise reduction technologies on CLT floors is available in literature, using such a source. For these reasons, this research presents the results of acoustic measurements using rubber ball and tapping machine for impact noise and dodecahedral source for airborne noise. Tests were carried out in situ in a timber building featuring CLT floors. The measurements were made step-by-step during the construction phase, firstly considering the bare CLT floor and after all the various layers.