Tascam MMR-8 - Manual (Page 49)

TASCAM MMR-8 Owner’s Manual • Chapter 3 • MMR-8 Keys and Status Displays 49
The bottom level LED (-25) is a green presence indicator. Any time there is signal on the track there will
be an indication. The next three LEDs indicate signal levels of -12, -6 and 0 VU. The next two LEDs are
yellow and indicate +6 and +12 VU. The final two LEDs are red to indicate the audio peaks are at MAX
(3 dB below clipping) and CLIP, which means the signal has most likely exceeded the input capability of
the digital converter and may be distorted. The CLIP indicator acts as a peak-hold indicator during
recording. It is only reset when the MMR-8 is stopped and put into PLAY again.
A de-facto film/video industry standard for digital device monitoring is that 0 VU should be set to
indicate a signal level of -20 dBFS (decibels below full scale, i.e. 20 dB below the digital clipping level).
The MMR-8 default setup follows this recommendation with the MAX LED indicator set to turn on with
a signal 17 dB above the nominal 0 VU indication (just before all bits would be set true in the ADC). The
CLIP indication is typically adjusted for a 3 dB hotter signal (20 dB above 0 VU). These settings can be
adjusted in 1dB increments using Setup mode menu 520 (Meter Reference Level) for any dB reference
level from -15 dBFS to -24 dBFS.
When the Meter Calibrate function (Menu 521) is on (for accurate field calibration of the inputs), the
LED’s reference steps are changed to indicate levels above and below 0 as +/- 1/3 dB, +/-1.0 dB, and +/-
3dB steps to allow fine tuning of input calibration levels. See Chapter 8, Maintenance and Service for
instructions on calibrating the inputs and outputs using the meters.
Machine Status LEDs
To the left of the LCD are 12 LEDs used to indicate the status of various MMR machine states (interlock,
calibrate, busy, lock, etc.), as well as the master record states (safe, destructive, 24-bit, etc.). These are
described here:
•
The SAFE LED will light when menu 201 (All Safe) is set to On, indicating that the MMR-8 will not
go into record.
•
The DESTRUCTIVE LED will be lit when menu 200 (Record Mode) is set to Auto-Cleanup or Tape
Mode. This indicates that all recordings will be destructive (i.e. any new recording will replace audio
already existing on the recorded track between the punch in & out points).
•
The 24-BIT REC (24-bit recording on) LED is controlled by menu 700 (Disk Encoding). When the
LED is lit, all audio is recorded in 24-bit file format. When the LED is off, 16-bit file format is used.
•
The DIG IN LED (Digital In) will be lit when menu 500 (Input Source) is set to Digital or Rate
Converter.
•
The TONE LED is lit when menu 530 (Reference Tone) is set to On. Pressing play when this LED is
lit will cause all channels to output a 1kHz reference tone at 0 VU.
•
The MIDI LED is used to indicate a valid MIDI input signal (MMC) is being received.
•
The ERROR LED indicates an error state has occurred and must be cleared before normal operation
can resume.
•
The BUSY LED indicates the system is occupied with a task, and the transport keys are not available
until the system finishes the current task and the Busy LED goes out.
•
The LOCK LED indicates the system is locked to the incoming machine synchronization source
(usually time code, biphase, or the MMR Bus).
•
The CAL LED indicates the Calibration function (Menu 521) is on.
•
The OFFSET LED indicates there is an offset (value other than 0) in the offset register (local MMR
offset) or when there is an MMR bus offset and the unit is a slave on the MMR bus.
•
The INTERLOCK LED lights when the system is in Biphase Chase Control Mode.