Longitudinal wave and seismic P-waves (created by earthquakes and explosions). In longitudinal waves, the displacement of the medium is parallel to the propagation of the wave, and waves can be either straight or round. A wave along the length of a stretched Slinky toy, where the distance between coils increases and decreases, is a good visualization. In the case of longitudinal harmonic sound waves, the frequency and wavelength can be described by the formula where: The quantity "x"/"c" is the time that the wave takes to travel the distance "x". The ordinary frequency ("f") of the wave is given by The wavelength
The Crests Jarmels. Former Jarmels member Ray Orta was also called in as a fill-in replacement for Joe Rivera. On December 12, 2017, J.T. Carter's Crests performed at The Paramount Theatre in Asbury Park, New Jersey, along with over 40 other groups from the 1950s and '60s, as part of TJ Lubinsky's new PBS TV Special, "Doo Wop Generations" (part of the "My Music" series). The special aired nationally in the US on PBS on March 3, 2018. The group was featured singing "The Angels Listened In" on the PBS television broadcast, as well as "Step By Step" listed on the CD/DVD