Sound quality in cochlear implants (CIs) remains a major challenge despite substantial progress in speech understanding. Many CI users achieve good speech recognition yet describe sounds as unnatural or distorted. A certain degree of this degradation may arise from “frequency-to-place factors” that affect how sound information is distributed along the cochlea and delivered to the auditory system - namely frequency-to-place mismatch (FTPM), neural responsiveness and current spread. Understanding these factors is crucial to optimise CI mapping and improve both sound quality and music perception. We developed two complementary psychoacoustic tasks to assess how these factors shape perception. (1) Vowel identification: Participants identified vowels generated from controlled combinations of the first and second formants, designed to stimulate electrodes independently. Each response included a confidence rating, enabling estimation of internal vowel maps and potential FTPM-related shifts. (2) Chord quality: Participants compared the sound quality of chords and their inversions using paired-comparison ratings, allowing assessment of electrode-specific degradation in complex harmonic sounds. Sixteen adult CI users (12 post-lingual, 4 pre-lingual) and normal-hearing controls were tested. One post-lingually deafened user was also followed longitudinally from switch-on to assess early adaptation. Individual X-ray and PECAP data provided physiological estimates of frequency-to-place alignment, current spread, and neural responsiveness. Preliminary results show high test–retest reliability. Several CI users preferred slightly shifted vowels, suggesting adaptation to FTPM. Chord comparisons revealed large electrode-specific variability, reflecting ENI differences. Together, these methods offer individualised insights into CI perception and hold promise for guiding clinical fitting to enhance naturalness and musical enjoyment.