## 6 Conclusions and Future Work  
It was shown that people who had played different musical instruments than the guitar before the experiment were able to perform the basic chords (C, D, E, F, G, A, B), and some chord transitions, with greater ease than individuals without any prior experience with musical instruments. Those with no musical instruments experience needed a longer amount of time to correctly perform the chords. That said, there was one anomaly in the results: The C chord proved to be the easiest chord for participants without musical knowledge to play, and the times recorded for this group proved faster than the times recorded for the group containing individuals with prior experience playing musical instruments. As participants were able to practice how to play chords in a single 1 h session, the proposed AR system is deemed to have produced satisfactory results. Observations made during the experiment revealed that experienced participants demonstrated greater patience when using the AR model, while those with no experience of musical instruments sought to play the chord as quickly as possible (and often incorrectly). All participants, regardless of age, fully accepted the proposed technology. That said, the authors recognise that the analysed age ranges differ only slightly (18-21 and 22-25). Therefore, it would be advisable to gather and analyse data from wider range of ages, for example children or the middle aged. Previous research based on learning to play the guitar using AR systems often focuses on the effectiveness of the system. Regarding user perception with the proposed system, [PERSON] [9] mentions \"all users agreed that the system is easy to use and that the visualization process is satisfactory. Besides, participants found the interaction techniques very useful and easy to use in contrast to commercial software learning tools. In terms of the technical part of the evaluation, as expected, most of the users preferred the monitor-based visualization versus the Head Mounted Displays - based visualization\". Besides, users comment on the drawback that the use of marks is a disadvantage since it must always be in front of the camera. [PERSON] et al. [21] conducted a SUS like the one presented in this article and obtained a similar evaluation of the usability of the system. In cases where there is mention of user perception, participants indicated that it is easy to use and that they were interested in learning. The proposed training system delivers results that reveal significant difference by gender, both in terms of playing chords and playing short melodies. The data show that men perform both tasks faster than women. However, based on the research data and our observational findings it was not possible to determine why men are faster. The tasks require that participants possess both physical dexterity as well as spatial skills. Given that they need the ability to interpret the movements demonstrated by the 3D model, it is worth questioning whether spatial ability might be a determining factor. Several studies have indicated that, generally speaking, men have better spatial awareness than women as a result of different factors. This statement has even been reaffirmed in conclusions drawn from more recent research [34-37]. The research described in this paper showed that it is easier for individuals with prior experience playing musical instruments to play acoustic guitar using AR. The degree of usability of the model is acceptable. Therefore, students feel comfortable interacting with the model and can use it to train in their free time without the need for a teacher [38], which supports that AR technology is appropriate in the first training steps. The results obtained show that the 3D model also has a positive impact on people without any prior experience with a musical instrument other than the guitar. Data shows that more than 85% of the tests were completed within the established time limit. Based on the findings, the authors recommended teaching beginners the C chord first.