 In the late 1960s and early 1970s, bands and solo artists began using the VOCODER to blend speech with notes played on a synthesizer.Meanwhile, at Bell Laboratories, Max Matthews worked with researchers Kelly and Lachbaum to develop a model of the vocal tract to study how its prosperities contributed to speech generation.Using the model of the vocal tract, Matthews used linear predictive coding (LPC)—a method in which a computer estimates the formants and spectral content of each word based on information about the vocal model, including various applied filters representing the vocal tract—to make a computer (an IBM 704) sing for the first time in 1962.