Transport Control Operation; A Eject - Alesis ADAT Reference Manual

the maximum possible signal level. Signals above 0dB will be clipped and lead to
digital distortion—an ugly, splattering sort of sound.
As on most digital recorders, O dB on the ADAT meter is referenced to full scale, the
maximum signal that can be recorded in 16 bits. Reference-level signals plugged into
ADAT are recorded 15 dB below full scale. For example, if your mixer has +4 dBu
balanced outputs that are connected to ADAT's +4 dBu multipin ELCO connector (or it
has -10 dBV unbalanced outputs connected to ADAT's 1/4" phone jacks), when your
mixer's meter reads 0 VU, the ADAT meter will read -15 dB. Therefore, you can run
your mixer levels "into the red" over 0 VU and still not distort the ADAT until the
mixer's meter reads "+15". Just remember that no matter what, if ADAT's meters
indicate 0 dB (highest red LED lit), distortion is on the verge of occurring.
Theoretically, the lowest noise and distortion in an ADAT recording occurs just as the
highest input peaks barely reach 0 dB full scale. Unlike analog recorders (which get
more and more distorted with higher levels), an ADAT tape that is recorded "in the
yellow" will sound great. However, in setting levels you must strike a balance
between what you gain by recording at high levels, and what you might lose if the
incoming signal hits the "digital brick wall" above 0 dB and distorts on a peak. This is
especially true in live recording, where peak levels are hard to predict. You must also
be careful when setting levels to make sure that the mixer isn't distorting. In critical
situations, consider limiting the input signal using the Alesis 3630 Compressor/Limiter
to ensure against overload and get a maximum level without distortion.
The ADAT meters are the instantaneous peak reading type: any voltage, no matter
how short, will be registered, because the peak level is all that matters to ADAT.
Other meters (as on most mixing consoles) may have different ballistic characteristics
or show average level instead of peak. It is normal for them not to match the ADAT
meters exactly. The RMB Remote Meter Bridge provides peak metering for four
ADATs in a rack-mountable package, and can be mounted above the console or the
BRC Master Remote Control. The RMB also features peak-hold features that make it
easier to avoid distortion.
3.4

TRANSPORT CONTROL OPERATION

The transport controls resemble those of a conventional tape recorder, although there
are several extra features.

3.4A Eject

Press to eject the tape from ADAT. If the tape is moving, it will stop before ejecting.
Note: This control does not operate while recording or formatting to avoid interrupting
these processes.