**3. The methodology used for the in-site measurements**

The four environments have some features of open-air places. However, bearing in mind studies on the evaluation of outdoor space acoustics [39], we analysed them using a closed concert hall acoustic method. This decision was taken after considering three factors. The first concerns the openness of the places: the four environments can be seen as boxes in which the floor and walls are made of stone, and the ceiling of the most absorbent material that ever existed, because no sound will bounce in the open air. The second consideration for the decision concerns size: the smallest environment, the Carrer de Santa Llúcia, holds an air volume of 1800 m3 , which makes it similar to a typical hall for speeches; the largest environment, the Plaça del Rei with a volume of 12,000 m3 , does not exceed the volume of a big concert hall such as the Berlin Philharmonic Concert Hall. Finally, the third consideration explains that in an open-air environment, the sound sources change their position every moment. This situation could be definitive if we were studying the soundscape of an everyday configuration, with running children, singers, street vendors or even police sirens. However, we are recording the place in a street concert configuration, and this means that there is one player at a fixed point and the listeners stand up in the quietest mode.

The measurement methodology was *previous controlled reproduction.* This method consists of the previous recording of an acoustic signal in an anechoic chamber and the following recording of the same signal in the environment. Subsequently, the two signals are compared. The first of the recordings in the anechoic chamber were made with a calibrated reproduction system and a calibrated recording system. The reproduction system consisted of a directional speaker LD 90 W connected to a 230 V power supply. It was positioned in one of the corners of the anechoic chamber. The recording system consisted of RODE NT-55 pair-matched microphones connected to a ZOOM H6 handy recorder on a stand. This recording system was positioned in the middle of the chamber, which was 2.5 m from the speaker. Additionally, the anechoic measurements were recorded with a HATS system connected to a laptop (**Figures 1** and **2**).

The in-site measurements were performed with the same equipment as the anechoic chamber measurements, except the HATS system. The distance of the measurements varied in each environment, as shown in **Figure 3**:

only in Plaça de Sant Felip. Track 16 (the initial measures of Puccini's *Nessum Dorma*) was reproduced in Carrer de Santa Llúcia due to the usual type of music played in this environment. Tracks 14 (initial measures of Victoria's choral work *O sacrum convivium*) and 15 (a flute-guitar piece by Dvorak) were played in Plaça de Sant Iu. Finally, track 19 (initial measures of Orff's *Carmina Burana*) was recorded in Plaça del Rei. The dates of the recording

Evaluation between Virtual Acoustic Model and Real Acoustic Scenarios for Urban Representation

http://dx.doi.org/10.5772/intechopen.78330

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**Track Plaça de Sant Felip Neri Carrer de Santa Llúcia Plaça de Sant Iu Plaça del Rei** 1. La oboe 30/3/2017 24/04/2017 07/04/2017 06/04/2017 2. Brahms 30/3/2017 24/04/2017 07/04/2017 06/04/2017 3. Mendelssohn 30/3/2017 24/04/2017 07/04/2017 06/04/2017 4. Tchaikovsky 30/3/2017 24/04/2017 07/04/2017 06/04/2017 5. 63 Hz 30/3/2017 24/04/2017 07/04/2017 06/04/2017 6. 160 Hz 30/3/2017 24/04/2017 07/04/2017 06/04/2017 7. 400 Hz 30/3/2017 24/04/2017 07/04/2017 06/04/2017 8. 1000 Hz 30/3/2017 24/04/2017 07/04/2017 06/04/2017 9. 2000 Hz 30/3/2017 24/04/2017 07/04/2017 06/04/2017 10. 4000 Hz 30/3/2017 24/04/2017 07/04/2017 06/04/2017 11. White noise 30/3/2017 24/04/2017 07/04/2017 06/04/2017 12. Pink noise 30/3/2017 24/04/2017 07/04/2017 06/04/2017 13. Shotgun 30/3/2017 24/04/2017 07/04/2017 06/04/2017

14. Victoria 07/04/2017 15. Dvorak 07/04/2017

16. Puccini 24/04/2017

**Table 1.** Relation of tracks played and recordings at the environments.

The four environments were studied using a reproduction-recording system. In this system, an impulse signal previously calibrated in the Anechoic Chamber was emitted in the environment. This signal was captured in different positions in each environment, as already mentioned. **Figure 3** shows the measured positions. Each of the recording points was subdivided into two channels corresponding to left (L) and right (R). Therefore, the naming of each recording consists of the number of the recording point, followed by an underscore and

19. Orff 06/04/2017

are as follows (**Table 1**):

**4.** *What* **is evaluated?**

17. Stravinsky 30/3/2017 18. Lucien 30/3/2017

capital letter L or R: 1\_L, 1\_R, 2\_L, 2\_R, etc.

**Figure 1.** Recordings in the anechoic chamber of Universitat Politècnica de València, Gandia.

**Figure 2.** Recordings in Plaça de Sant Felip Neri, Barcelona.

**Figure 3.** The plans of the four environments: Plaça de Sant Felip Neri, Carrer de Santa Llúcia, Plaça de Sant Iu, Plaça del Rei.

To ensure uniform measurements, some were repeated in the four environments, while others were recorded in specific places, considering the normal musical use of the environments. Tracks 1–13 were repeated in the four environments. However, tracks 17 (the final part of Stravinsky's *Firebird Suite*) and 18 (a solo harp piece by Lucien) were reproduced only in Plaça de Sant Felip. Track 16 (the initial measures of Puccini's *Nessum Dorma*) was reproduced in Carrer de Santa Llúcia due to the usual type of music played in this environment. Tracks 14 (initial measures of Victoria's choral work *O sacrum convivium*) and 15 (a flute-guitar piece by Dvorak) were played in Plaça de Sant Iu. Finally, track 19 (initial measures of Orff's *Carmina Burana*) was recorded in Plaça del Rei. The dates of the recording are as follows (**Table 1**):


**Table 1.** Relation of tracks played and recordings at the environments.
