Musical instrument tuners are devices that help musicians to adjust their instruments such that the played notes have the desired fundamental frequencies. In a conventional tuner, the reference tuning frequencies are preset, where the presets are obtained from tuning (musical scale) theory, such as twelve-tone equal temperament, or are user-specified temperaments. For many kinds of music in oral traditions, especially nonwestern music, widely accepted theoretical presets for tuning frequencies are not available because of the use of non-standard tunings. For such contexts, the “reference” is a master musician or a recording of a master musician. In this article, a tuning method and technology are presented that help the musician to tune the instrument according to a given (user-provided) recording. The method makes use of simultaneous audio and visual feedback during the tuning process, in which novel approaches are used for both modalities. For audio feedback, loopable stable frames, obtained automatically from the recording, are looped and played continuously. For visual feedback, a superimposed plot of the auto-difference functions is displayed instead of the conventional tuner's approach of detecting frequencies and displaying the amount of frequency difference between the input and the reference.