Preliminary insights into combinations of instrumental timbres and their listenability for deaf and hard of hearing individuals

The listenability of sounds affects how accessible music is for individuals who are deaf or hard of hearing (DHH). We investigated the listenability of instrumental music for DHH individuals through a beat-tapping task using smartphones in everyday listening conditions. Four short music pieces (32 beats, two rhythmic patterns), each with melody and accompaniment, were rendered with 10 timbre combinations at three tempi. Based on prior research, we used four instruments: shamisen (SHM), piano (APF), accordion (ACC), and recorder (REC). Timbres were labeled as XXXYYY, where XXX indicates the melody instrument and YYY the accompaniment (e.g., ACCAPF). We defined a tapping performance index (TPI) using the harmonic mean of recall (correct taps / 32) and precision (correct taps / total taps), assuming higher TPI indicates better listenability. A non-parametric analysis (Friedman test with Durbin–Conover post-hoc) revealed significant differences: (1) SHMREC was less listenable than APFAPF, SHMSHM, and ACCAPF; (2) RECREC than APFAPF and SHMSHM; and (3) SHMACC than ACCAPF. While the sample size was limited (n = 13), these differences suggest meaningful patterns in how instrumental timbre combinations affect beat perception for DHH listeners. Further research will examine how acoustic features and individual auditory characteristics shape listenability.