Loop bin duplicator: Difference between revisions

Revision as of 22:34, 15 November 2016

Revision as of 22:35, 15 November 2016

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While this loop is being played back, the audio signals for the A and B side (or all 4 programs for 8-track) are sent to a "slave" recorder or an audio bus that contains multiple "slaves". The "slave" records from the loop bin master the 4 tracks for both A and B sides to a reel of raw 1/8" audio tape (for cassettes) or all 8 tape tracks to back-lubricated 1/4" audio tape (for 8-track cartridges) wound on a "pancake" reel (similar to [[film|motion picture film]] wound on a plastic core) at the same high speed. After it is recorded, this pancake of tape is then loaded onto special machines called loaders. For cassettes, the loader has cassette shells containing only a leader called "C-0" cassettes that are loaded one at a time or into a hopper where the C-0s are fed automatically depending on the type of loader. The tape from the pancake is then spliced onto the C-0 cassette's leader and then wound into the cassette by the loader. For 8-tracks, the tape is wound from the slave recorder onto a device mounted on its side, called a "sidewinder", which holds several small reels, and extracts and winds the tape from the slave recorder onto each reel into an endless-loop configuration (with the tape being pulled from the center of the wind), where each full reel is then placed in an empty 8-track cartridge and spliced together, either by machine or by hand, with a foil splice that holds the loop together. The foil splice also serves to automatically engage an 8-track player to advance to the next program when played.

The loop of tape in the duplicator usually will have a segment of clear leader spliced in between the beginning and end of the program (with some duplicators using a metal foil splice instead). This clear leader splice is read by an optical sensor (or in the case of a foil splice, coming in contact with electrical contacts in the tape path) in the loop bin duplicator, which triggers a cue tone that is recorded to the reel of pancake tape. This cue tone is read by the loader, and engages it to stop and cut the tape from the pancake and either splice it to the other length of leader in the cassette shell for cassettes, or to engage and disengage winding and then cut the tape to an internal cartridge reel on the "sidewinder" mechanism for 8-tracks (a process for both types of media called "de-spooling"), with the winding resuming to a new reel afterwards. In fact, part of this de-spooling tone (also known as a "tailor tone" or "trigger tone") can be heard at the leader splice or foil splice of some previously recorded audio cassettes and 8-tracks respectively, as a very low-frequency [[arpeggio|arpeggiated]] rumbling, (very much like how [[Motorboating (electronics)|"motorboating"]] sounds with a radio or audio amplifier affected by such), but as an actual tone when played back at a higher speed.

In the [[XDR (audio)|XDR]] duplication process for audio cassettes, the loop bin duplicators use 1"-wide loop tape instead (like what is used for 8-track duplication), yielding in a better quality duplication.