744T User Guide and Technical Information

Once a file is recorded its sample rate and bit depth can not be changed in the recorder. The 744T can not perform sample rate conversion or bit depth changes. File conversion must be done in another environ- ment, such as an audio workstation. Alternatively, a real-time analog transfer is often performed instead of sample rate conversion.

Time Code

The 744T uses time code circuitry developed by Ambient Recording GmbH, a leading developer of stable, portable time code products (visit Ambient on the web at www.ambientaudio.com). Clock stability and continuity are critical aspects of the 744T time code implementation. Its temperature- controlled (compensated) crystal oscillator ensures rock solid TC stability and accuracy (< 0.2 ppm when tuned with an Ambient Mastercontroller).

The 744T holds accurate time code for up 8 hours between battery changes using its internal, rechargeable AA NiMH time code cell. This time code battery is charged from internal or external power whenever the 744T is powered up.

Non-linear file-based recordings place a single time code number in the data header of an AES31 (.BWF) file. The 744T generates SMPTE time code from this number and extrapolates it based on the time code frame rate for playback.

Frame Rate

Time code frame rate is selected in the Timecode:Framerate menu.

The 744T supports the most common production time code rates:

•23.976 – used with Sony high definition video cameras

•24 – to sync audio to film where no transfer to NTSC video is expected

•25 – to sync sound to PAL video

•29.97 – to sync sound to NTSC video shot in non-drop frame mode and Panasonic high defini- tion cameras

•29.97DF - to sync sound to NTSC video shot in drop frame mode

•30 – to sync sound to film where transfer to NTSC video is expected

•30DF – to sync sound to film for transfer to NTSC video in drop-frame mode 30 fps

Time Code Mode

The 744T has five time code modes: off, Free Run, Record Run, Continuous Jam, and 24 Hour Run.

Off:

The time code generator is disabled. The front panel time code display is blank.

Free Run:

The internal time code generator runs continuously without regard to the record mode. Time code value defaults to 00:00:00:00, a user entered value, or the value last in the internal generator. The user can jam any start value into the generator from the jam menu.

Record Run

The time code generator runs only when the 744T is recording. Time code in this mode defaults to

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firmware v. 1.04 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.