The sensitivity of total‐field receptions to sound‐speed profile choice is analyzed using ray theory. The profiles are depth dependent, and may be used to describe a deep‐ocean sound channel. A variety of locations of a fixed source and receiver, separated by less than about 50 km, is considered. Given a specified profile and a second, simpler profile constructed by procedures previously described [J. Acoust. Soc. Am.75, 112–124 (1984)], it is demonstrated that the acoustic fields associated with the profiles are negligibly different. Approximations for total‐field phase and amplitude differences are presented, which facilitate the determination of those ranges where the total fields match closely. In addition, the sensitivity of performance measures for horizontal linear receiving arrays to profile selection is studied. Expressions for normalized power pattern are developed which incorporate certain nonplane‐wave effects associated with an assumed dominant ray arrival. Conditions are presented for which a simpler profile may replace a specified profile and still maintain nearly equivalent array performance.