F Sampling Rate Modes; 48.048K And 48.048Kf; Fostex Dv40; 47.952K And 47.952Kf - Sound Devices 788T User Manual And Technical Information

788T User Guide and Technical Information

F Sampling Rate Modes

48.048k and 48.048kF

The 48.048kF mode (F stands for fake, faux, Fostex—take your pick) is a specifi c compatibility mode
for use with the Fostex DV40 software (1.74 and previous), Avid, Final Cut Pro, and other post-pro-
duction environments that do not recognize audio fi les written at 48.048 kHz. In this mode fi les are
recorded at a 48.048 kHz sampling rate but are stamped at 48 kHz. When played, they will play back
0.1% slower than real time.
One use for the 48.048kF mode is to force a 0.1% speed reduction (pull down) of audio to match
MOS-telecined fi lm (24 fps-to-NTSC) in non-linear edit systems, such as Avid or Final Cut Pro. Since
the fi le is stamped as a 48 kHz fi le, the edit system will play it back at 48 kHz and not at 48.048 kHz.
This "audio pull down" will match the transferred picture without the need for an intermediate step
through other software to create the pull down.
The time code frame rate (actual recording rate) is forced to 30 ND in 48.048kF mode. The LCD dis-
play will show 30 ND during recording. No other frame rate is available in 48.048kF mode.
the file is recorded at 48.048 k, 30 ND
The audio fi le, however, is stamped with a 29.97 ND frame rate, along the 48 kHz sampling rate. It
will appear as if the fi le was originally recorded at a 48 kHz sampling rate at a TC rate of 29.97 ND.
on playback, file appears at 48 k, 29.97 ND

Fostex DV40

When using fi les recorded in the 48.048kF mode in with a DV40 with early software, set the DV40
time code frame rate to 29.97ND. Time code stamps will properly match the original time code start
times.

47.952k and 47.952kF

Both 47.952 and 47.952kF settings use a record sampling rate of 47.952 kHz, 0.1% lower than 48
kHz. The 47.952kF mode, however, identifi es the fi le as being recorded at 48 kHz. Additionally, in
47.952kF mode, the time code rate is restricted to 29.97ND, while the fi le is identifi ed as 30ND.
47.952F mode is useful in applications where the 788T is recording in high-def environments with
cameras at 23.97 and post production is using a straight 24 frame session.
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