An interference-based exhaust noise attenuation device and method for
exhaust flow from an internal combustion engine that generates
compressive waves in the exhaust flow. The device includes at least a
direct path for the exhaust flow; a looped path for the exhaust flow,
with volumes of the direct path and the looped path differing by an
amount that results in a staggered rearrangement of the compressive waves
in the paths; a splitter that splits the exhaust flow into the direct
path and the looped path; and a merger that merges the exhaust flow from
the direct path and the looped path. When the exhaust flow from the
direct path and the looped path are merged, at least some noise
cancellation occurs. In other embodiments, plural direct paths, looped
paths, splitters, and/or mergers can be used in various combinations.