This research attempts to replicate the report of Carterette, Friedman, and Lovell [J. Acoust. Soc. Amer.45, 986–998 (1969)] who indicated the existence of auditory masking effects similar to Mach bands in vision. Threshold for sinusoids in narrow bands of noise were estimated for five listeners using an adaptive psychophysical procedure. The data show little, if any, similarity to Mach band effects, but rather are in line with what would be expected based on a traditional critical band concept.