The present quantitatively-driven mixed methods study aimed at exploring the effect of musical input as a mode on intermediate L2 learners' knowledge and retention of difficult words. The data were collected in two phases. In the experimental phase, quantitative data were collected from 40 learners. An innovative method was used for the purpose of developing the treatment in the quantitative phase. That is, we composed music for each difficult word to be utilized as an input mode in the treatment condition. In the qualitative phase, a subset of the quantitative sample took part in the semi-structured interviews. The quantitative results of this explanatory mixed methods study showed that the use of music as a mode positively affected the learners' learning and retention of the meaning of difficult words. However, the qualitative findings did not fully confirm the quantitative results.