User manual

662
Synchronization
Working with VST System Link
The only exception to this procedure is if you are using an external clock – from a
digital mixing desk or a special word clock synchronizer, for example. In that case you
must leave all your ASIO cards in clock slave or AutoSync mode and make sure that
each of them is listening for the signal coming from the synchronizer. This signal is
usually passed through your ADAT cables or word clock connectors in a daisy chain
fashion.
VST System Link and latency
The general definition of latency is the amount of time it takes any system to respond
to whatever messages are sent to it. For example, if your system’s latency is high and
you play VST instruments in realtime, you will get a noticeable delay between when
you press a key and when you hear the sound of the VST instrument. Nowadays, most
ASIO-compatible audio cards are capable of operating with very low latencies. Also,
all VST applications are designed to compensate for latency during playback, making
the playback timing tight.
However, the latency time of a VST System Link network is the total latency of all the
ASIO cards in the system added together. Therefore it is extra important to minimize
the latency times for each computer in the network.
Ö The latency does not affect the synchronization – it is always perfectly in time. But it
can affect the time it takes to send and receive MIDI and audio signals, or make the
system seem sluggish.
To adjust the latency of a system, you adjust the size of the buffers in the ASIO control
panel – the lower the buffer size, the lower the latency. It is best to keep to fairly low
latencies (buffer sizes) if your system can handle it – about 12
ms or less is usually a
good idea.
Setting up your software
Now it is time to set up your programs. The procedures below describe how to set
things up in Cubase. If you are using another program on the other computer, please
refer to its documentation.
Setting the sample rate
The projects in both programs must be set to use the same sample rate. Select
“Project Setup…” from the Project menu and make sure that the sample rate is the
same in both systems.
Streaming digital audio between applications
1. Create input and output busses in both applications and route these to the digital
inputs and outputs.
The number and configuration of the busses depend on your audio hardware and
on your needs. If you have a system with eight digital i/o channels (such as an
ADAT connection), you could create several stereo or mono busses, a surround
bus together with a stereo bus, or any combination you need. The important thing
is that you should have the same configuration in both applications – if you have
four stereo output busses on computer 1, you want four stereo input busses on
computer 2, etc.
2. Set things up so that computer 1 plays back some audio.
For example, you could import an audio file and play it back in Cycle mode.
3. In the Inspector or MixConsole, make sure that the channel containing the audio
material is routed to one of the digital output busses.