## 2 Methods
### Case Studies  
The case studies correspond to five soundscape campaigns carried out by Tecnalia from 2011 to 2014, with 534 evaluations by individuals, in 10 places considered analysis units. Each analysis unit corresponds to a homogenous urban area (HUA) with similar acoustic characteristics, functionality and use.  
These places are part of 5 urban environments (spaces) located in Bilbao (Basque Country, Spain). The studies were carried out as part of several projects that applied the concept of \"islas sonoras\", or sound islands (led by Bilbao City Council) [24; 25], and the QUADMAP LIFE project [26].  
The urban spaces and places are (Figure 1):  
1. Paseo del Arenal (2011): Pedestrian urban square located in Bilbao's historical district, considered the best way of entering the city's old quarter. This space was subdivided into 3 places, differentiated by their functionality and use, but which have similar acoustic characteristics: 1. Playground zone (1.1): An area containing playground equipment for children, where the main sound sources are the voices of children and their carers. 2. Trees (1.2): The place closest to the estuary. It contains dense vegetation, as well as small pools and water fountains along the 3 walkways comprising it. The predominant sound sources are voices, footsteps and running water. 3. Walkway (1.3): Place connecting the square with the old quarter of Bilbao, where the main sound sources are traffic and human voices.
2. Plaza Nueva (2011): Pedestrianised urban square located in Bilbao's historical quarter surrounded by arcaded buildings. This space was subdivided into 3 places with common acoustic characteristics, but differentiated by their functionality and use: 1. Arcades (2.1): Covered, arcaded walkway, close to nearby bars (human sound sources) where people get together to socialise. 2. Centre (2.2): Open area in the centre of the square that is used mainly by children playing. The main sound sources are children's voices. 3. Terraces (2.3): Open zone close to the arcades, for use by clients of the nearby bars (bar terraces), where the main sound sources are human voices.
3. Plaza Levante (2012): A small square situated in the San Ignacio neighbourhood, close to the underground entrance. This place is used for spending time in as well as being a pedestrian thoroughfare (3.1). The predominant sound sources are road traffic (buses) and people (voices and footsteps).
4. Plaza San Pedro Deusto (2012): Space located in the Deusto neighbourhood, near the church of San Pedro de Deusto and the main urban traffic thoroughfare in the area. The place selected corresponds to the area containing large plane trees, mainly used for spending time in, as well as being a pedestrian thoroughfare (4.1). The main acoustic sources are traffic, human voices and footsteps.
5. Plaza General Latorre (GLT): Urban square located in the Basurto neighbourhood. It was renovated to make it the city's first sound island, according to soundscape criteria, as part of the LIFE QUADMAP European project [26]. The place was evaluated prior to its renovation in 2012 (5.1) and afterwards (2014) (5.2). Initially, it was a noisy square (road traffic), with poor access and primarily used by elderly people. The refurbishment led to an enormous improvement in this public space and its acoustic comfort, as traffic sources now coexist with the noise of humans and water fountains.  
Figure 1: Images of the five public spaces and specific analysed units.  
This study includes people's different uses of each of these places. At the different locations analysed, the predominant use is as a place to pass time (except in the centre of Plaza Nueva) and as thoroughfares (except for the playground area in Paseo Arenal and the terraces of Plaza Nueva). Recreational use is fundamentally limited to the zones where children play (the playground in Paseo del Arenal, the central area of Plaza Nueva, and Plaza General Latorre after renovation) although Plaza Nueva and Plaza GLT have no specific facilities for this purpose.