Figure 1.

Schematic of probe tips. Panels: Source characteristics as a function of frequency. Similar characteristics were observed using the ER10-14 (dark gray) and modified ER10D (light gray) tips. The dotted black lines are the source characteristics obtained with the ER10D tip using four acoustic loads with overlapping resonant peaks at 17.5 kHz (see Fig. 2), and the solid black lines are the source characteristics obtained with the same tip using five acoustic loads with non-overlapping resonant peaks.