Sample rate, Clock source, Sample rate clock source – Teac X-48MKII User Manual

Page 36: 5 – recorder

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36

TASCAM X-48MKII

Video Clock
Video Clock gives a precise frame edge to the SMPTE

timecode. Not available as a clock reference.
SMPTE Timecode
SMPTE Timecode is used as a location reference,

defining where in the timeline to locate to.
MIDI Timecode
MIDI Timecode (MTC) is sometimes used as a location

reference with MIDI sequencing software or computer-

based DAW software
RS-422
In addition to receiving playback, record and other

transport commands, track record arming can also be

controlled
As these reference sources are all related, you can see

the importance of making sure that all of your devices

are resolved to the same clock reference. Another way to

look at sync on the X-48MKII is to examine the order that

things happen when the X-48MKII is online:
1. The X-48MKII either sees a transport command from

the RS-422 signal or sees SMPTE timecode and goes

into play.

2. The X-48MKII looks at either the SMPTE input or the

RS-422 to determine where in the timeline to

begin playback.

3. If enabled, the X-48MKII looks to the video clock input

for a more exact timestamp for the incoming SMPTE.

4. Once the X-48MKII is locked to the right SMPTE frame,

it starts playing at the rate dictated by its sample clock

source.

5. If the input SMPTE drops out or is otherwise

interrupted, playback (or recording) will stop while

the timecode is interrupted depending on the Chase

Freewheel setting. Moreover, if the input timecode and

the unit’s timecode drifts beyond the Relock Threshold

value, the input timecode will either be rechased or

the drift will be ignored and playback will continue

depending on the Chase Relock setting.

6. When SMPTE timecode stops or an RS-422 stop

command is received, the transport stops.

Sample Rate

A sample rate should be chosen when first creating a

project, with consideration to what will be done with the

final product. Your choices are:

44100 (CD standard)

48000 (DVD standard)

88200 (2x CD standard)

96000 (2x DVD standard)

42336 (44.1k conversion from film (24) to PAL (25))

44056 (44.1k pull-down)

44144 (44.1k pull-up)

45938 (44.1k conversion from PAL (25) to film (24))

46080 (48k conversion from film (24) to PAL (25))

47952 (48k pull-down)

48048 (48k pull-up)

50000 (48k conversion from PAL (25) to film (24))

84672 (2x 44.1k conversion from film (24) to PAL (25))

88112 (2x 44.1k pull-down)

88288 (2x 44.1k pull-up)

91875 (2x 44.1k conversion from PAL (25) to film (24))

92160 (2x 48k conversion from film (24) to PAL (25))

95904 (2x 48k pull-down)

96096 (2x 48k pull-up)

100000 (2x 48k conversion from PAL (25) to film (24))


If you change the sample rate after audio has been

recorded, that audio will play back at a different pitch. To

change the sample rate:

Mouse/Keyboard Operation

1 Click the Windows menu and select the Settings

window.

2 Click the Sync tab and set the sampling frequency

using the Rate item in the Sample Clock section.

Front Panel Operation

1 Press the SYNC button. Press the

5

/

b

buttons to

select

Sample Rate

and press CHNG.

2 Select a sample rate from the list using the

5

/

b

buttons and press Enter.

3 When

Changing Sample Rate OK?

appears,

press the ENTER/YES button.

Clock Source

One of the most important settings on the X-48MKII is the

sample clock source, which governs playback speed and

keeps audio pops from happening. There are five choices.
Internal
Internal is the default. This can be used if the X-48MKII

is either used by itself, with an analog console or as the

master clock for the studio.
Word Clock
Word Clock should be used when you have an external,

dedicated master clock available. The word clock

generator needs to be set to the same sample rate as the

X-48MKII.
S/PDIF
S/PDIF clocks the X-48MKII from the digital audio signal

coming into the S/PDIF Digital Input.

5 – Recorder

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