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ISDN (Sound Improvements)


By Derek Casari
Ever wondered what it takes to record actors these days? The process of replacing lines in a feature film or TV show is technically known as ADR, which stands for Automated Dialog Replacement. The purpose of ADR is to record cleanly, dialog from the set that is unusable or to add additional dialog. It was originally known as “looping,” because in the early days of recording, the machines did not have the ability to erase. Consequently, a “loop” of magnetic film was placed on a 35 mm magnetic recorder and the actor repeatedly spoke his/her lines until it was decided “sync” was acceptable. Things have progressed substantially since then. 35mm magnetic recorders have nearly become extinct. Today, actors are still cued by a series of three beeps, but no longer do we need to record on one track, instead we record to multitrack digital machines. The standard today is a multitrack hard disc based system known as Pro Tools made by Digidesign. Another popular system is an 8-track hard disk recorder called an MMR 8 made by Tascam, which can record a Pro Tools compatible session.
With the increasingly hectic timeline for postproduction, there has been a shift towards the use of ISDN. ISDN is an acronym for Integrated Services Digital Network. These are special digital phone lines that when used in conjunction with a codec (encoder/decoder), allows for two channels of very high quality audio. An actor can be in a studio anywhere in the world and can connect to any other studio, appropriately equipped. On one channel is placed the actor’s audio and on the other channel is placed a synchronization signal called time code. The studio in the remote location “drives” the session and feeds audio and time code to the “slave” location. The audio on channel 1 is recorded and the time code on channel 2 is used to lock up an exact copy of the videotape on the opposite end. In this manner, the director or supervising editor can see the picture in sync locally, despite the fact that the talent is somewhere else on the planet.
When the session is over, the editor can begin cutting the lines into the picture immediately. A variation of this can be having the talent in L.A. and when recording is finished, the audio file is compressed with a program called “Stuffit” and then send to the remote facility via an application called “ftp” (file transfer protocol). The time and cost savings of this method of looping are noteworthy. No longer does the talent have to be shuttled to the studio, rather they can go to a facility that is geographically desirable for them. In many cases, they have completed the movie they need to loop, and are on to their next picture somewhere else.

Derek Casari, currently an engineer at a motion picture studio, has worked for Sony, Todd-AO, Vidtronics and Ampex over the past 20 years.

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