Stretched-octave tones whose only partials are stretched octave partials were generated on the Sampson Digital Synthesizer according to the relation Fn = anFo. where n = 1,2,4…. These partials are separated by distances greater than a critical band yet subject reports of difference in tone quality suggest an interaction among the partials. For a = 2. a tone with octave partials only has been traditionally perceived as thin and clear. [J. R. Pierce, J. Acoust. Soc. Am. 40, 249 (1966); IRCAM communication, April 1976]. Departures from a = 2 show progressively greater variance from this percept. The expected beats of mistuned octaves are heard in these tones only with great difficulty and under special conditions. An explanation for the change in tone quality was sought by looking at the rate of phase change between partials. Reasons for interaction phenomena in such widely stretched partials are discussed.