The purpose of this investigation was to explore the feasibility of a probe tube microphone technique as a procedure which would lead to improved S/N ratios on recordings made synchronously with laryngeal photographic records. Recordings were made of the vowel "a" at poinst ranging from six inches in front of the oral aperture to three inches within the oral cavity. In addition, measurements were made of camera noise at selected points in relation to the oral cavity. It was found that in the presence of high level camera noise, superior S/N ratios are associated with recordings made directly within the oral cavity. It was also noted that the results of probe tube experiments must be interpreted with the knowledge that the spectra of intra-oral recordings differ from those spectra obtained for recordings made outside the oral cavity. Finally, the critical effect of the size of the oral aperture on the resultant S/N ratio was discussed.