Perception of the simple difference tone (f2-f1).

The present study examined the dependence of difference tone level [L(f2-f1)] on the following parameters of the two-tone input: f1, f2/f1 (f2 greater than f1), L1, L2, and L1 = L2. Difference tone levels were estimated in four normal hearers using a 2AFC adaptive temporal gap-masking paradigm. The key finding in this study is the apparent interaction of each factor with the other. For example, primary level (L1 = L2) was found to affect the dependence of L(f2-f1) on f1 and on f2/f1. In addition, the frequency separation of the primaries (f2/f1) was also seen to exert an influence on the dependence of difference tone level on L1, L2, and L1 = L2.