Four experiments are reported that deal with pitch perception of harmonic complex tones containing up to 11 successive harmonics. In particular, the question is raised whether the pitch percept of the missing fundamental is mediated only by low-order resolvable harmonics, or whether it can also be conveyed by high-order harmonics that the cochlea fails to resolve. Melodic interval identification performance was found to remain significantly above chance level even if the range of harmonics extended from the 20th to the 30th. Just-noticeable differences (jnd) in the pitch of the missing fundamental were found to increase with increasing harmonic order, but to level off when all harmonics are above the 12th. These results are consistent with the notion of the existence of two distinct neural pitch mechanisms in the auditory system, but are, in principle, also compatible with a single central-spectrum mechanism that uses the interspike interval histograms of auditory-nerve fibers as inputs.