A system or apparatus can provide electrostimulations via an electrode configuration that can be selected from multiple electrode configurations, the electrostimulations of the type for inducing a desired heart contraction, or a neurostimulation response. For example, the media playing pipeline includes one or more components synchronized for media playing. The passage has an inner surface, which defines a plurality of peaks and valleys, wherein the height of each peak is greater at the first end of the passage than at the second end of the passage and the height of each valley is greater at the first end of the passage than at the second end of the passage.