9.5

Synchronization
Working with VST System Link
RESULT
Typically, the ASIO control panel for an audio card contains some indication of whether or not the
card receives a proper sync signal, including the sample rate of that signal.
This is a good indication that you have connected the cards and set up clock sync properly. Check
your audio hardware’s documentation for details.
IMPORTANT
It is very important that only one card is the clock master, otherwise the network cannot function
correctly. Once you have set this up, all the other cards in the network will take their clock signal
from this card automatically.
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.
IMPORTANT
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
PROCEDURE
1. Create input and output busses in both applications and route these to the digital inputs
and outputs.
585