A feature of the homophonic barbershop style is an emphasis on major and dominant seventh chords which are sung with little vibrato and with pitches adjusted to achieve tuned chords in just intonation. A principal resource for the investigation reported here was the library of online recordings of the 2016 and 2017 international competitions sponsored by the Barbershop Harmony Society. These recordings provide a wealth of examples of the barbershop sound. They include hundreds of quartet samples performed in a context that features a uniform expectation of what constitutes good sound, along with uniform recording conditions and ranking by judges who serve as expert listeners. A large number of spectra were obtained for a loud, sustained major chord on an open vowel. Tuning of these chords was investigated, and for each sample a spectral contour was constructed with amplitudes normalized to simplify comparisons. From the consistency of these spectral contours it is possible to obtain a picture of the timbral features that distinguish the barbershop sound. In addition, patterns of relatively small differences in spectral envelope among the samples are strongly correlated with the ranking of the quartets by the competition judges.