PURPOSE: to check the effects of a speech therapy intervention, based on the educational practice, by the assessment of speech and language pathologists, singing teachers and amateur choral singers themselves, analyzing the parameters of breathing, projection and vocal range profile in singing voice, pre and post speech therapy intervention. METHODS: the program was the theoretical framework of Zabala (1998) on educational practice. Ten amateur choral singers responded to a characterization questionnaire and conducted recordings of vocal range and singing, pre and post intervention. During six meetings, we approached warm up, anatomy and physiology as for the singing voice, vocal health, breathing and voice perception. The recordings were analyzed by judges (speech therapists and singing teachers) that assessed breathing, projection and vocal range profile. The choristers, without access to the recordings, made self-assessment of those parameters. RESULTS: evaluation of judges: vocal range had more positive changes, followed by breathing and vocal projection. All parameters had significant changes (p <0.01). Speech therapists analyzed the vocal range more in line with expectations, singing teacher considered the projection, and breathing data showed results statistically equivalent. The results by subject showed that two singers had improvements in all parameters and seven of them, at least, in two of the parameters. The singer's perception showed improvements in all aspects. CONCLUSION: the intervention had positive effects on the choir and showed the need for studies that may evaluate the process itself, in order to enhance the speech therapist acting on the singing voice.