Singing is a cultural universal and an important part of modern society, yet many people fail to sing in tune. Many possible causes have been posited to explain poor singing abilities; foremost among these are poor perceptual ability, poor motor control, and sensorimotor mapping errors. To help discriminate between these causes of poor singing, we conducted 5 experiments testing musicians and nonmusicians in pitch matching and judgment tasks. Experiment 1 introduces a new instrument called a slider, on which participants can match pitches without using their voice. Pitch matching on the slider can be directly compared with vocal pitch matching, and results showed that both musicians and nonmusicians were more accurate using the slider than their voices to match target pitches, arguing against a perceptual explanation of singing deficits. Experiment 2 added a self-matching condition and showed that nonmusicians were better at matching their own voice than a synthesized voice timbre, but were still not as accurate as on the slider. This suggests a timbral translation type of mapping error. Experiments 3 and 4 demonstrated that singers do not improve over multiple sung responses, or with the aid of a visual representation of pitch. Experiment 5 showed that listeners were more accurate at perceiving the pitch of the synthesized tones than actual voice tones. The pattern of results across experiments demonstrates multiple possible causes of poor singing, and attributes most of the problem to poor motor control and timbral-translation errors, rather than a purely perceptual deficit, as other studies have suggested.