This paper provides an overview of some of the ways in which the output from the electrolaryngograph enables aspects of the vibrating vocal folds during singing and speech to be monitored non-invasively. This paper was presented at the British Voice Association Symposium in honour of the work of Adrian Fourcin on 9 May 2009 at University College London; Adrian developed the electrolaryngograph itself and researched and promoted its use as a practical device for use both clinically and in the speech sciences laboratory. Here, the application of the electrolaryngograph for voice source investigations relating to singing in a number of situations is considered, including: singing in different styles, tuning accuracy and vocal blend in unaccompanied (a capella) quartet singing, and longitudinal aspects of voice development in girl choristers.