Steinberg Nuendo 3 Operation Manual

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VST System Link 26 – 601
5.Now, you need to make sure that one audio card (and only one!) is set 
to be the Clock Master, and all the other cards must be set to listen 
for the clock signal coming from the Clock Master i.e. they must be 
Clock Slaves.
The naming and procedure for this differs depending on the audio hardware – consult 
its documentation if required. If you are using Steinberg Nuendo ASIO hardware, all 
cards default to the “AutoSync” setting – in this case you must set one of the cards 
(and only one) to “Master” in the Clock Mode section of the control panel.
•Typically, the ASIO control panel for an audio card contains some in-
dication of whether the card receives a proper sync signal or not, and 
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.
It’s very important that one and only one card is the clock master, other-
wise 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 – which could be from a digital mixing desk or special Word 
Clock synchronizer for example. If so, you must then 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, 
usually passed through your ADAT cables or Word Clock connectors 
in a daisy chain fashion.
Minimizing the latency
The general definition of latency is the amount of time it takes any sys-
tem to respond to whatever messages are sent to it. For example, if 
your system’s latency is high and you play VST instruments in real 
time, 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. 
						

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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’s extra important to minimize the latency times for each computer in 
the network.
• The latency does not affect the synchronization – it's always perfectly in 
time. But, it can affect the time it takes to send and receive MIDI and au-
dio signals, or make the system seem sluggish.
To adjust the latency of a system, you typically adjust the size of the 
buffers in the ASIO control panel – the lower the buffer size, the lower 
the latency. Generally speaking it's 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’s time to set up your programs. The procedures below describe 
how to set things up in Nuendo; 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 
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 depends on your audio hardware and on 
your needs. If you have a system with eight digital i/o channels (such as an ADAT con-
nection), you could create several stereo or mono busses or 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 bus-
ses 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.
You could for example import an audio file and play this back in Cycle mode.
3.In the Inspector or mixer, make sure the playing audio channel is 
routed to one of the digital output busses you set up. 
						

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VST System Link 26 – 603
4.In Computer 2, open the mixer and locate the corresponding digital 
input bus.
The audio being played back should now “appear” in the program running on Com-
puter 2. You should see the input bus level meters moving.
5.Reverse this procedure so that Computer 2 plays back and Computer 
1 “listens”.
Now you have verified that the digital connection works as it should.
• From this point on in this chapter, we refer to the busses connected to 
the digital inputs and outputs as “VST System Link busses”.
Settings for the audio hardware
When you send VST System Link data between computers, it is im-
portant that the digital information isn’t changed in any way between 
the programs. Therefore, you should open the control panel (or addi-
tional application) for your audio hardware and make sure that the fol-
lowing conditions are met:
•If there are additional “format settings” for the digital ports that you 
use for VST System Link data, make sure these are turned off.
For example, if you are using an S/P DIF connection for VST System Link, make sure 
that “Professional format”, Emphasis and Dithering are turned off.
•If your audio hardware has a mixer application allowing you to adjust 
the levels of digital inputs and outputs, make sure that this mixer is 
disabled or that the levels for the VST System Link channels are set to 
(± 0 dB).
•Similarly, make sure no other forms of DSP (pan, effects, etc.) are ap-
plied to the VST System Link signal.
Notes for Hammerfall DSP users
If you are using RME Audio Hammerfall DSP audio hardware, the 
Totalmix function allows for extremely complex signal routing and mix-
ing in the audio hardware. This can in some situations lead to “signal 
loops” in which case the VST System Link won’t work. If you want to 
make absolutely sure this won’t cause any problems, make sure the 
default or “plain” preset is selected for the Totalmix function. 
						

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Activating VST System Link
After setting up the inputs and outputs, you now need to define which 
input/output should carry the actual VST System Link information.
The System Link networking signal is carried on only one bit of one 
channel. This means that if you have an ADAT based system which 
normally carries eight channels of 24-bit audio, once you activate VST 
System Link you will have seven channels of 24-bit audio and one 
channel of 23-bit audio (the least significant bit of this last channel is 
what we will use for networking). In practice this makes no discernible 
difference to the audio quality, since you will still have around 138dB 
headroom on this channel.
To set things up we need to open the VST System Link panel:
1.Open the Device Setup dialog on the Devices menu.
2.Select the VST System Link device from the VST Audiobay subpage.  
						

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3.Use the ASIO Input and ASIO Output pop-up menus to define which 
channel should be the networking channel (and thus become a 23-bit 
audio channel, in our example).
Quite often you will be able to just leave these pop-ups the way they are. 
4.Click the Active checkbox at the top of the panel.
5.Repeat the steps above for every computer on the network. 
As the computers are made active, you should see the small T (Trans-
mit) and R (Receive) lights flashing on each active computer, and the 
name of each computer should appear in the list at the bottom of the 
pane. Each computer is assigned a random number – don't worry 
about this, it's just so the network knows internally which one is which.
•You can double click on the name in bold (which is the name of the 
computer you’re currently working on) and set it to whatever other 
name you wish.
This name will appear in the System Link window of every computer on the network.
• If you don't see the name of each computer appearing once you have 
made it active, you may have to check your settings. 
Go through the procedure above again and make sure that all ASIO cards are listening 
to the digital clock signals correctly, and that each computer has the correct inputs 
and outputs assigned to the System Link network.
Putting the network online
After each computer's name you will see whether it is online or not. 
When a computer is online, it will receive transport and timecode 
signals, and its sequencer application can be started and stopped by 
remote control. If it is off-line it can only be started from its own key-
board – it is effectively an independent machine, although it is still on 
the network.
• Note that any computer can control any and all of the others – VST Sys-
tem Link is a peer to peer network and there is no absolute “master” 
computer.
However, most users do like to think of one machine as the master (in a one person/two 
computer network, this would be the machine you actually sit behind most of the time). 
For now, let's put all computers online: 
						

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1.Activate the Online checkbox in the VST System Link panel for all 
computers. 
2.Check that the system is working by pressing Play on one computer – 
all computers should start almost instantly and play perfectly in time, 
with sample accurate precision.
•The Offset setting to the right allows you to adjust whether one ma-
chine will play back slightly ahead or behind the rest.
This is normally not needed, but occasionally with some hardware you may find that the 
lock is a few samples out. In that case you can adjust the lock with the Offset value. For 
now, leave it set to 0 – it will most likely be what you want.
VST System Link sends and understands all transport commands, so 
you can play, stop, fast forward, rewind etc. the entire network from 
one computer without a problem – try it! If you jump to a locator point 
on one machine, all other machines will also instantly jump to that lo-
cator point. You can even scrub on one computer and have the video 
and audio on another computer actually scrub right along with you.
Don't forget to make sure that all computers have their tempos set to the 
same value, otherwise your synchronization will be seriously skewed.
Using MIDI
As well as supplying transport and sync control, VST System Link also 
supplies up to 16 MIDI ports, each with 16 channels. You set this up 
as follows:
1.Use the MIDI Ins and Outs value boxes to specify the number of MIDI 
ports you need.
The default value is 0 MIDI In and 0 MIDI Out ports.
2.Create a MIDI track in the Project window and open the Inspector 
(top section).  
						

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VST System Link 26 – 607
3.If you now pull down the “in” or “out” pop-ups, you will find the spec-
ified System Link ports added to the list of MIDI Inputs and Outputs.
This allows you to route MIDI tracks to VST instruments running on 
another computer, as described in the application examples (see 
page 611).
The “Active ASIO Ports for Data only” setting
If you are sending huge amounts of MIDI data at once, there is a small 
possibility that you might run out of bandwidth on your VST System 
Link network. This will manifest itself by notes “choking” or timing be-
coming erratic.
If this happens, you can devote more bandwidth to MIDI by selecting 
Active ASIO Ports for Data only in the VST System Link Setup panel. 
When this is active, the VST System Link information will be sent on 
the entire channel instead of just one bit, more than enough for all the 
MIDI you could ever hope to use. The downside is that you can no 
longer use this ASIO channel for audio transfer (do not connect it to a 
speaker!), thus leaving you only 7 channels of audio in our ADAT ca-
ble example. Depending on how you work this might be a reasonable 
compromise.   
						

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26 – 608 VST System Link
Hearing the network audio
If you are using an external mixing desk, hearing your audio really isn't 
an issue – just plug the outputs of each computer into the desired 
channels on the external mixing desk, press Play on one of the com-
puters, and you're good to go.
However, many people prefer to mix internally inside the computer and 
just use a desk for monitoring (or maybe not use any external mixer at 
all). In this case you'll need to select one computer to be your “main 
mix computer” and send the audio from your other computers into this.
In the following example, we assume you are using two computers, 
with Computer 1 as your main mix computer and Computer 2 running 
two additional stereo audio tracks, an FX channel track with a reverb 
plug-in and a VST instrument plug-in with stereo outputs.
1.First you want to set things up so that you can listen to the audio play-
back from Computer 1.
In other words, you need an unused set of outputs, e.g. an analog stereo output, con-
nected to your monitoring equipment.
2.Go to Computer 2 and route each of the two audio tracks to a sepa-
rate output bus.
These should be busses connected to the digital outputs – let’s call them Bus 1 and 2.
3.Route the FX channel track to another VST System Link bus (Bus 3).
4.Route the VST instrument channel to yet another bus (Bus 4).
5.Go back to Computer 1 and check the corresponding four VST Sys-
tem Link input busses.
If you start playback on Computer 2, the audio should “appear” on the input busses on 
Computer 1. However, to mix these audio sources you need actual mixer channels:
6.Add four new stereo audio tracks on Computer 1 and route these to 
the output bus you use for listening, e.g. to the analog stereo outputs.
7.For each of the audio tracks, select one of the four input busses.
Now, each Computer 2 bus is routed to a separate audio channel on Computer 1.
8.Activate monitoring for the four tracks. 
						

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If you now start playback, the audio from Computer 2 will be sent 
“live” to the new tracks on Computer 1, allowing you to hear them to-
gether with any tracks you play back on Computer 1.
Adding more tracks
OK, but if you have more audio tracks than you have VST System Link 
busses (physical outputs)? Then you just use the Computer 2 mixer 
as a submixer: Route several audio channels to the same output bus 
and adjust the output bus level if needed.
Note also that if your audio cards have multiple sets of input and out-
put connections you can link up e.g. multiple ADAT cables and send 
audio via any of the busses on any of the cables.
Internal mixing and latency
One problem with mixing inside the computer is the latency issue we 
mentioned earlier. The VST engine always compensates for record la-
tencies, but if you are monitoring through Computer 1 you will hear a 
processing delay while you listen to signals coming from your other 
computers (not on your recording!). If your audio card in Computer 1 
supports ASIO Direct Monitoring you should definitely turn this on – 
you'll find the setting in the VST Audiobay Device Setup panel (see 
page 63). Most modern ASIO cards support this function. If yours 
doesn't you may want to change the Offset value in the VST System 
Link Setup panel to compensate for any latency issues.
Setting up a larger network
This is not much more difficult than a two computer network. The main 
thing to remember is that VST System Link is a daisy chain system. In 
other words, the output of Computer 1 goes to the input of Computer 
2, the output of Computer 2 goes to the input of Computer 3, and so 
on around the chain. The output of the last computer in the chain must 
always go back into the input of Computer 1, to complete the ring.
Once you've done this, the transmission of all the transport, sync, and 
MIDI information to the whole network is handled pretty much auto-
matically. However, where you may run into confusion in a large net-
work is in the transmission of audio signals back to a central mix 
computer. 
						

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If you have lots of hardware inputs and outputs on your ASIO cards you 
don't need to send audio via the chain at all, but can transmit it directly 
to the master mix computer via one or more of its other hardware In-
puts. For example, if you have a Nuendo Digiset interface or 9652 card 
on Computer 1 you could use ADAT cable 1 for networking, ADAT ca-
ble 2 as a direct audio input from Computer 2, and ADAT cable 3 as a 
direct audio input from Computer 3.
You can also transmit audio via the ring system if you don't have 
enough hardware I/Os for direct audio transmission. For example, in a 
four computer scenario you could send audio from Computer 2 into a 
channel in the mixer in Computer 3, and from there to a channel in the 
mixer in Computer 4, and from there back to the master mixer in Com-
puter 1. This can certainly be tricky to set up, so generally it is recom-
mended that if you want to set up a complex network, you should 
make sure to use ASIO cards with at least three separate digital I/Os.