MOTU MIDI Express XT [60/94] Ltc mode

SYNCHRONIZATION

There are several ways to handle this. One way is to leave

an empty track on your multi-track tape deck as a buffer

between the time code and other tracks. With a buffer

track, time code can be recorded at very strong (“hot”)

levels (above 0 VU) without risk of bleedthrough.

If your tape deck has no tracks to spare, a good level at

which to record is around –3 VU. That is, the VU meter for

the time code track on your tape deck should read –3

when you stripe the time code. This records time code that

is hot enough for reliable lockup and weak enough so that

it will not bleed into adjacent tracks. -3 VU is only a rule of

thumb, though, so don’t hesitate to use other levels if they

work better for you.

LTC MODE

In LTC mode, your Express interface locks to incoming

time code received on its SMPTE IN jack. But LTC mode

differs from LTC QuikLock mode (page 42) in several

signiﬁcant ways. In LTC mode, your Express interface:

■ Emits regenerated LTC on its SMPTE OUT jack

■ Analyzes incoming time code and responds in several

useful ways, depending on what happens to the incoming

time code

■ Measures incoming time code with an extremely

accurate internal clock to see how fast or slow it is running

and displays the results in the SMPTE Reader window in

ClockWorks

Because LTC mode employs a sophisticated phase-lock

synchronization engine in your Express interface, the

amount of time it takes to establish lockup to incoming

time code is longer than LTC QuikLock mode. On the

other hand, LTC mode offers the additional capabilities

mentioned above. These features, and how you can use

them, are discussed in the next few sections.

Regenerating fresh time code (‘jam syncing’)

Time code is a problem when you are copying tapes: it

degrades rapidly every time you try to copy it from one

tape to another. Often, the time code signal deteriorates so

much that it will not be recognizable by any SMPTE-to-

MIDI converter, including your Express interface, and you

will no longer be able to lock to it.

!USB Interfaces Manual Book Page 60 Tuesday, August 16, 2011 11:21 AM