**5.1. Usability evaluation**

We could define usability as a general quality that indicates the suitability for a specific purpose of a particular artefact (appropriateness for a purpose) [48].

This term is linked with the development of products (which could be systems, technologies, tools, applications or devices) that can be easy to learn, effective and enjoyable in the user's experience. Nevertheless, usability can be considered another factor in a wider process called the acceptability of a system. Thus, acceptability defines whether a system is good enough to meet all a user's needs [49].

In ISO/IEC 9126, usability is defined as "software product capability to be understood, learned, used and attractive for the user, when it is used under specific conditions." However, usability is not limited to computer systems. It is a concept that can be applied to any element in which an interaction between a human and an artefact occurs.

In addition, in ISO/IEC 9241-11, the guidelines for the usability of a particular product are described. Here, usability is defined as "the level in which a product can be used by particular users in order to reach specified goals with effectivity, efficiency and satisfaction in a particular context of use." In our research, the effectivity of a system is related with its goals, efficiency is related with the performance of the used resources to reach the goals, and satisfaction is related with its acceptability and commodity [50]. This definition is based on the concept of *quality in use*, and describes how the user does particular tasks in particular environments in an effective way [51]. For Bevan, the quality of use, measured in terms of efficiency, efficacy and satisfaction, is not only determined by the product, but also by the context (kind of users, tasks of the users and physical environment). Therefore, the usability, understood as the quality in use of a product is the interaction between a user and a product while a task is being accomplished in a technical, physical, social and organisational environment.

In our study, usability defines the general quality, indicating the suitability for educational purposes of an immersive scenario. In a similar line as [52], the goal is to evaluate the student motivation before and after the use of such technologies. Users are asked to evaluate the quality of the soundscape representation in this scenario. Both visual and acoustic data have a direct impact on the perception of the space and the realism of this representation is the focus of the evaluation.

acoustic and sonic features of the outdoor space, and to obtain feedback on the most relevant

**index MI (%) for option A**

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

**Option B Mention** 

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

**100** C50 (500 Hz) = −7.5 dB (from

track)

**29.4** EDT (500 Hz) = 2.3 s

**82.4** (Plaça del Rei, recording

**58.8** (Plaça Sant Iu, recording point 4, Dvorak track)

**88.2** T60 (500 Hz) = 1.75 s (from **Figure 4**, Plaça del Rei, recording point 4, Orff track)

**82.4** (Plaça Sant Felip Neri,

track)

**Figure 5**: Carrer Santa Llúcia, recording point 3: Puccini

point 1, Tchaicovsky track)

(from **Figure 8**: Plaça del Rei, recording point 4, Mendelssohn track)

recording point 4, Lucien

**index, MI, (%) for option B**

57

**0**

**17.6**

**70.6**

**41.2**

**11.8**

**17.6**

The results should allow for an initial approximation of whether people are aware of the nuances and differences between a street music recording and a concert hall music recording. Above all, it should be possible to test people on the big differences between the acoustics of the different public spaces. Therefore, different recordings of the same music but from different spatial points were compared. A total of six questions, each with a new melody, covered the following topics: speech intelligibility, sense of space, reverberation time, timbre

The first dataset (**Tables 2** and **3**) shows the description of the analysed elements and the

After an analysis of the survey results, we can highlight some important findings. First, all the questions in **Table 2** are balanced to A or B over 70%, except the fourth question, which is more ambiguous. This shows the high consensus about the acoustic features that were being evaluated. Second, we highlight the presence of users who had professional or higher music qualifications in **Table 3**. These users agreed unanimously, or almost unanimously (except one) in their decisions. The only question on which they disagreed with each other concerns

aspects of street music.

the sense of space.

modification, EDT and bass amplification.

**E. Code Description Option A Mention** 

**Figure 5**: Carrer Santa Llúcia, recording point 1,

point 3, Tchaicovsky track)

**Figure 8**: Plaça Sant Felip Neri, recording point 1, Mendelssohn track)

point 1, Dvorak track)

**Figure 4**, Plaça del Rei, recording point 1, Orff

recording point 1, Lucien

Puccini track)

1. I Speech clarity (C50) C50 (500 Hz) = 2 dB (from

2. S Sense of space (Plaça de Sant Iu, recording

3. EDT Early decay time EDT (500 Hz) = 1.3 s (from

4. Br Brightness (Plaça Sant Iu, recording

5. T60 Reverberation time T60 (500 Hz) = 0.65 s (from

6. BR Bass ratio (Plaça Sant Felip Neri,

track)

track)

**Table 2.** Description and definition of the options in the quantitative test.

individual responses of the different users.
