LP-28  Theater Speaker Silencer

The LP-28 is designed to cut speakers to absolute silence in mixing theaters, ADR / foley stages, broadcast studios, etc. It contains 2 independent channels with a nominal power capacity of 1,000 watts per channel. Connections to sound source and amplifier inputs are via balanced XLR connectors.
Connections to amplifier outputs and speakers are via Speakon type connectors. All line and speaker signals are floating and not referenced to the LP-28 ground. Logic drive signals are applied via optocouplers (1 per channel) and signals can be positive or negative logic, momentary or latching, from 5 volts to 24 volts with an internal or external reference.
A rear panel dip switch is provided for logic programming and formatted drive signals may be paralleled between units for multi-speaker systems.

Muting Procedure: Signal from the console is muted with a balanced, dual reed relay; 10 milliseconds later, a 15 ohm power resistor is connected in parallel with the speakers; another 10 milliseconds later the speaker line is open. The complete sequence takes 25 milliseconds, but the signal is muted after 2 milliseconds. Reverse sequence results in de-muting.

 

Front and rear panel of the LP-28 in PDF format, click here.

Lafont Users Include:

4MC; All Post; American Zoetrope; AstralTech; Brasher Sound; Buzz Audio; Bark Audio; C.B.S. TV; Casablanca Sound; Chace Productions; Chicago Audio; Chicago Pacific Recording; Cliff Schwarz Recording; Cinar Films; Creative Cafe; Enterprise Post; Flying Monkey; International Recording; Location Sound; Magno Sound; Millennium Studios; Medallion PFA; Post Modern Sound; Novastar; Olympic Sound Studios; Sonolab; Soundfirm; Paramount Pictures; Premier Post; Signet Sound; Skywalker Sound; Sony Pictures; Sound One; The Beach; The Walt Disney Company; Todd AO Studios; Universal Pictures; Virtuality Recording; Warner Brothers; Warrenwood Studios; Westwind Media; 20th Century Fox

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