Difference limens (DLs) were measured at 30, 60, and 75 dB SPL per critical band. The stimuli were a 1000-Hz tone, a partially-masked 1000-Hz tone, an 18-tone complex consisting of equally intense harmonics (F0 = 110 Hz) encompassing frequencies from 110 to 7260 Hz, and a uniformly masking noise. The DLs were measured in a 2I, 2AFC paradigm with an adaptive procedure. The stimulus duration was 500 ms; the interstimulus interval was 250 ms. The results for the three listeners are very similar. The DLs for the pure tone decrease from 1.3 dB at 30 dB SPL to between 0.33 and 0.7 dB at 75 dB SPL. The DLs for the partially masked tone stay relatively constant around 1 to 1.6 dB with increasing level, except for one listener whose DL at 75 dB SPL is clearly smaller than at the lower levels. The results for the noise and the tone complex are similar, showing little level dependence with DLs between 0.4 and 0.8 dB. Generally, these results are consistent with the multi-band excitation-pattern model [Florentine and Buus, J. Acoust. Soc. Am. Suppl. 1 67, S22 (1980)].