The sound absorbing board includes a body and multiple sound absorbing elements. The body has a first side surface and a second side surface. The multiple sound absorbing elements are formed on the body at spaced intervals, and each one of the multiple sound absorbing elements has a protrusion, a groove, and two sound absorbing openings. The protrusion is formed on the first side surface of the body. The groove is formed on the second side surface of the body and has multiple concave portions and at least one convex portion. The multiple concave portions are formed on a bottom surface of the groove. The at least one convex portion is formed on the bottom surface of the groove, and is formed between two adjacent ones of the multiple concave portions. The two sound absorbing openings are formed on the two opposite side surfaces of the protrusion, respectively.

The present inventive concept relates to an interference noise-control unit, for installation on a sound arresting wall for reducing noise from trains or cars. The interference noise-control unit comprises: a housing to be secured on a sound arresting wall. The housing comprises a hollow compartment comprising at least one first channel and at least one second channel, wherein the first channel has a first channel height A and a first channel length B, and wherein the second channel has a second channel height A′ and a second channel length B′, and wherein the first channel height A is different from the second channel height A′.

A sound absorbing structure includes a wall having a first side and a second side and at least one acoustic scatterer coupled to a first side of the wall. The first side of the wall may be positioned to face a source of noise, such as moving motor vehicles, airplanes, and the like. The at least one acoustic scatterer has an opening and at least one channel. The at least one channel has a channel open end and a channel terminal end with the channel open end being in fluid communication with the opening.

The sound absorbing board includes a body and multiple sound absorbing elements. The body has a first side surface and a second side surface. The multiple sound absorbing elements are formed on the body at spaced intervals, and each one of the multiple sound absorbing elements has a protrusion, a groove, and two sound absorbing openings. The protrusion is formed on the first side surface of the body. The groove is formed on the second side surface of the body and has multiple concave portions and at least one convex portion. The multiple concave portions are formed on a bottom surface of the groove. The at least one convex portion is formed on the bottom surface of the groove, and is formed between two adjacent ones of the multiple concave portions. The two sound absorbing openings are formed on the two opposite side surfaces of the protrusion, respectively.

The disclosure relates to an interference noise-control unit comprising a housing to be secured on a sound arresting wall. The housing comprises a hollow compartment comprising at least one first channel and at least one second channel, wherein the first channel has a first channel height A and a first channel length B, and wherein the second channel has a second channel height A and a second channel length B, and wherein the first channel height A is different from the second channel height A.