Steinberg Cubase SX/SL 3 Operation Manual

							CUBASE SX/SLSynchronization 28 – 681
Synchronizing the transport vs. synchronizing audio
How timing is handled in a non-synchronized system
Let’s first look at the situation where Cubase SX/SL is not synchro-
nized to any external source.
Any digital playback system has an internal clock that ultimately affects 
the playback speed and stability, and PC audio hardware is no excep-
tion. This clock is extremely stable.
When Cubase SX/SL is playing back with no external synchronization, 
all playback is internally synchronized to the internal digital audio clock, 
to ensure synchronization between digital audio and MIDI.
Synchronizing Cubase SX/SL’s playback
Let’s assume now that we use external timecode synchronization, with 
Cubase SX/SL. For example, we might synchronize playback to a 
tape recorder.
Timecode coming from an analog tape recorder will always vary slightly 
in speed. Different timecode generators and different tape recorders 
will also supply timecode with slight differences in speed. In addition, 
the shuttling of tape mechanisms due to overdubs and re-recordings 
can cause the physical tape to wear and stretch, which affects the 
speed of the timecode.
If you set up Cubase SX/SL to sync to incoming timecode, it will vary 
its overall playback speed to compensate for such fluctuations in the 
speed of the timecode – that’s the whole purpose of synchronization.
What happens with the digital audio?
The fact that Cubase SX/SL’s playback is synchronized to the time-
code does not affect the playback of the digital audio. It still relies on 
the perfectly stable, built-in clock in the audio hardware.
As you may understand by now, problems will appear when the per-
fectly stable digital audio gets related to the slightly varying speed of a 
system synchronized to timecode.
The playback timing of each event will not be in total accordance with 
the tape or the MIDI playback, since the playback speed of the audio 
is determined by the digital audio hardware’s built-in clock. 
						

							CUBASE SX/SL28 – 682 Synchronization
Resolving to word clock
The solution to this problem is to use one external clock for all compo-
nents in the system. One master clock is used to derive whatever type 
of clock signal each component in the system needs. For example, 
something called a house clock can be used to generate sample rate 
clocks for the digital audio hardware and timecode for Cubase SX/SL. 
This ensures all components in the system use the same reference 
source for their timing.
Synchronizing digital audio to external clocks running at sample rate is 
often called “resolving” or “synchronizing to word clock”. 
If you aim to perform synchronization to external signals, we strongly 
recommend that you obtain proper synchronization equipment. This 
encompasses:
• An audio card that can be slaved to external word clock.
• A synchronizer that can read timecode (and possibly house clock) and gener-
ate the required sync signals from that, such as the Steinberg TimeLock Pro.
or...
• An audio system with complete built-in synchronization possibilities, prefera-
bly supporting the ASIO Positioning Protocol.
Using timecode without word clock
Of course, it is possible to set up a synchronization system where you 
lock Cubase SX/SL to timecode without using word clock. However, 
please note that the timing of audio vs. MIDI cannot be guaranteed 
and that fluctuations in speed in the incoming timecode will not affect 
the playback of audio events. This means that synchronizing to time-
code may work in the following situations:
•When the timecode was originally generated by the audio card itself.
•When the source providing the timecode is extremely stable (such as 
a digital video system, a digital tape recorder or another computer).
•When you remain synchronized to that same stable source through-
out the entire process, both while recording and playing back audio. 
						

							CUBASE SX/SLSynchronization 28 – 683
About the ASIO Positioning Protocol (APP)
ASIO Positioning Protocol requires audio hardware with specific ASIO 
drivers. As of this writing, APP is not available for audio hardware with 
non-ASIO drivers under Mac OS X.
The ASIO Positioning Protocol is a technology that expands on the 
type of sync described above and makes sample accurate positioning 
possible.
When transferring audio digitally between devices, it is important that 
synchronization using word clock and timecode is completely corre-
lated. If not, the audio will not be recorded at the exact intended (sam-
ple accurate) position, which can cause various types of problems, 
such as inaccurately positioned audio material, clicks and pops etc.
A typical situation is when transferring material from a digital multi-
track tape recorder to Cubase SX/SL (for editing) and then back 
again. If you do not have sample accurate synchronization set up, you 
cannot be sure that the material will appear in its exact original posi-
tion, when transferred back to the tape recorder.
In order to take advantage of the ASIO Positioning Protocol, your au-
dio hardware must be suitably equipped and the functionality must be 
included in the ASIO driver for the hardware.
An example of a system for doing sample accurate transfers, would be 
transferring audio tracks from an Alesis ADAT to Cubase SX/SL. Here 
the ADAT will be the sync master (though it doesn’t necessarily have 
to be). It provides both the digital audio (with an inherent word clock) 
and positional information (timecode) via its ADAT sync protocol. The 
master clock is generated by the ADAT itself.
Hardware and software requirements for APP
• Your computer audio hardware (in our example above this would be an ADAT 
card in your computer) must support all the functionality required for the ASIO 
Positioning Protocol. That is, it must be able to read the digital audio and the 
corresponding positional information from the external device.
• There must be an ASIO 2.0 driver for the audio hardware.
• For resolving to external timecode, the audio hardware must have a timecode 
reader/writer on-board. 
						

							CUBASE SX/SL28 – 684 Synchronization
• For information about which audio hardware models currently support APP, 
see the Steinberg web site (www.steinberg.net).
The ASIO Positioning Protocol exploits the specific advantage of having 
an audio card that has a built-in timecode reader. With such a card and 
the ASIO Positioning Protocol, you can achieve constant sample accu-
rate synchronization between the audio source and Cubase SX/SL.
Machine control
Cubase SX/SL can control external tape transports and similar de-
vices via MIDI Machine Control. This allows you to operate an external 
tape transport from Cubase SX/SL’s Transport panel. That is, Cubase 
SX/SL can make the tape recorder locate to a certain position, start, 
stop, rewind etc.
About sync and machine control
Controlling tape transports is a two-way process:
• Cubase SX/SL sends out machine control commands to the tape recorder, 
asking it to locate to a certain position and activate playback etc.
• The tape recorder locates to the requested position, starts and delivers time-
code back to Cubase SX/SL, to which Cubase SX/SL is synchronized.
Even though it appears as if Cubase SX/SL is controlling the tape re-
corder completely, it is important to remember that in this setup, Cu-
base SX/SL is still being synchronized to the external tape transport, 
not vice versa.
Also note that the two processes of sync and machine control are com-
pletely separated, in terms of protocols used. You can for example syn-
chronize to MTC while sending out transport commands via MMC.
MIDI Machine Control (MMC)
This is a standard MIDI protocol for controlling tape transports. There 
are a number of tape recorders and hard disk recording systems on the 
market that support this protocol. Cubase SX/SL allows you to control 
the transport of an external MMC device, and arm tracks for recording 
(Cubase SX only). 
						

							CUBASE SX/SLSynchronization 28 – 685
Window Overview
The Synchronization Setup dialog
This dialog is used for setting up everything that has to do with the 
synchronization of Cubase SX/SL to other units. You reach it from the 
Transport menu.
Settings for 
sync to exter-
nal timecode.
Options for 
incoming 
timecode.Input and Output 
for MIDI Machine 
Control messages.
Note that the “Num-
ber of Audio Tracks” 
option is valid for 
Cubase SX only.
Outputs for 
MIDI Clock.
Outputs for MIDI 
Timecode.
Input port for 
MIDI Timecode.  
						

							CUBASE SX/SL28 – 686 Synchronization
Operations
Making connections and basic settings
The descriptions below are for a basic setup with a separate synchro-
nizer and audio card. Depending on your exact situation and require-
ments for communication with external devices, there are endless 
variations on this theme. Please consult your dealer for more detailed 
recommendations.
The following connections are required for external sync via a synchro-
nizer, including resolving of the audio card. For details on audio card 
and synchronizer settings and connections, see the included manuals.
•Route the master clock signal (LTC, VITC, etc.) to an input on the syn-
chronizer.
•Connect the word clock output on the synchronizer to an input on the 
audio card.
•Connect the MIDI Timecode (MTC) output on the synchronizer to the 
corresponding input on the computer.
•Set up the synchronizer and make sure the frame rate settings are in 
accordance with the master clock.
For more information on frame rates, see page 694.
A typical synchronization setup.
Synchronizer MIDI Interface Video transportMIDI TimecodeWord Clock
to audio card
LTC Timecode Audio
Amplifier and
speakers 
						

							CUBASE SX/SLSynchronization 28 – 687
Setting up the audio card for external synchronization
1.Open the Device Setup dialog from the Devices menu and select the 
VST Audiobay page–name of your audio interface subpage.
2.Click the Control Panel button to open the card’s proprietary setup 
dialog.
If this card is accessed via a special ASIO driver (as opposed to MME or Direct X), this 
dialog is provided by the card, not by Cubase SX/SL. Hence the settings vary with the 
card brand and model.
3.Adjust the settings as recommended by the card manufacturer, then 
close the dialog.
The dialog may also contain various diagnostic tools that allow you to verify for exam-
ple whether word clock is arriving correctly.
4.From the Clock Source pop-up, select the input to which you routed 
the word clock signal.
This pop-up may not be used if you selected an input in the Control Panel dialog in-
stead.
Setting up Cubase SX/SL for external sync to timecode
1.In the Synchronization dialog, set Timecode Source to MIDI Timecode 
or ASIO Audio Device (only if your hardware is ASIO Positioning Pro-
tocol compatible).
2.For MIDI Timecode, use the pop-up menu in the MIDI Timecode 
Source section to select an input for the timecode.
If you are using the ASIO Positioning Protocol this is not required, since the timecode 
is then coming in directly via your audio hardware.
Sync settings for MIDI Timecode.
Sync to timecode activatedThe MIDI Input for the timecode  
						

							CUBASE SX/SL28 – 688 Synchronization
3.Close the Synchronization Setup dialog and instead open the Project 
Setup dialog from the Project menu.
4.Use the Start value to set which frame on the external device (e.g. a 
video tape) should correspond to the beginning of the project.
•You can also set this with the function “Set Timecode at Cursor” on 
the Project menu.
This is useful if you know that a certain position in your project would coincide with a 
certain timecode position in the external device. Move the project cursor to the desired 
position, select “Set Timecode at Cursor” and specify the corresponding timecode 
position in the dialog that appears – the Start value is adjusted accordingly.
5.In the dialog that appears, you are asked if you want to keep the 
project content at its timecode positions. Select “No”.
This will make all events and parts keep their positions relative to the project start. 
6.Close the Project Setup dialog.
7.On the Transport panel, activate the Sync button (or select Sync On-
line from the Transport menu).
8.Start the tape (or video, or...) that contains the timecode. Cubase SX/
SL starts playing when it receives timecode with a position “higher” 
than, or equal to, the project Start frame.
You can wind the device that sends the timecode to any position and 
start from there.
When the device with the timecode is stopped, you can use the Cubase 
SX/SL transport controls as you normally do, when it is not synchronized. 
You should also look into the Sync Options, see page 695.
Set this to the timecode 
position where you want 
the project to start. 
						

							CUBASE SX/SLSynchronization 28 – 689
The Sync indicator
On the Transport panel you can check the status of incoming timecode 
by observing the sync indicator. It switches between “Offline” (not 
waiting for sync), “Idle” (ready for sync but no signal is coming in), and 
“Lock xx” (where xx is indicating the frame rate of the incoming signal).
Synchronizing other Equipment to Cubase SX/SL
You may have other MIDI devices that you want to synchronize to 
Cubase SX/SL. There are two types of synchronization that Cubase 
SX/SL can transmit: MIDI Clock and MIDI Timecode.
Transmitting MIDI Clock
If you transmit MIDI Clock to a device supporting this type of synchro-
nization signal, the other device will follow Cubase SX/SL’s tempo. The 
tempo setting in the other device is of no relevance. Instead it plays at 
the same tempo as Cubase SX/SL. If the device also reacts to Song 
Position Pointers (which Cubase SX/SL transmits) it will follow when 
you wind, rewind and locate using the Cubase SX/SL Transport panel.
• MIDI Clock transport commands include “Start”, “Stop” and “Continue”. 
However, some MIDI equipment (e.g. some drum machines) do not 
recognize the “Continue” command. If this is the case with your equip-
ment, activate the option “Always Send Start Message” in the Synchro-
nization Setup dialog (MIDI Clock Destinations section).
When this is activated, only the Start command is used.
Transmitting MIDI Timecode
If you transmit MIDI Timecode to a device supporting this type of syn-
chronization signal, the device will synchronize time-wise to Cubase 
SX/SL, that is, the time displays on Cubase SX/SL’s Transport panel 
and on the other device will agree. When you wind and locate Cubase 
SX/SL and then activate playback, the other device will follow from 
the same position (if it has this capability and is set up for it!).
The Sync indicator 
						

							CUBASE SX/SL28 – 690 Synchronization
• If you want to be able to loop, jump and locate during playback in Cu-
base SX/SL and have the other device follow, activate the MIDI Time-
code Follows Project Time checkbox.
When this is activated the sent MIDI Timecode will follow the sequencer time position 
at all times.
Setting Up
1.Connect the desired MIDI Outputs from Cubase SX/SL to the device(s) 
that you plan to synchronize.
2.Open the Synchronization Setup dialog from the Transport menu.
3.Activate the sync outputs by using the corresponding checkboxes in 
the lower right part of the dialog.
You can output any combination of MIDI Timecode and MIDI Clock to any combination 
of outputs (however, you probably don’t want to send MTC and MIDI Clock to the 
same output).
Some MIDI Interfaces will automatically send MIDI Clock to all MIDI out-
puts, regardless of the MIDI Clock Port selection you make in Cubase 
SX/SL. If this is the case, you should only select one MIDI Clock Port 
(consult the documentation of the MIDI Interface if in doubt).
4.Set the other device(s) to their “external synchronization” mode (or 
some other mode with a similar name) and activate playback on them 
if necessary.
5.Activate playback in Cubase SX/SL, and the other device(s) will follow.
MIDI Timecode transmitted 
to Outputs 1 and 2.
MIDI Clock transmitted to 
Output 3.