Analog Audio
Digital 2-channel audio (S/PDIF, AES/EBU)
Digital Multi Channel Audio (e.g. ADAT Optical)
Word Clock
Possibilities
• The multiple outputs allow you to separate the channels in Cubase VST for further processing in an external mixer. See the chapter “The Input/Output Bus System” for details on how to map channels to outputs.
• Having multiple inputs allows you to record several separate Audio Tracks at once (using Multi Track Recording - see page 46), which is useful if you want to record several players at the same time, etc.
• As always when using an external mixer, it is necessary to use some kind of bus or send system for feeding signals to the inputs on the audio hardware, thus allowing you to select which signals should be recorded. Simply connecting the main outputs of the mixer to the audio hardware is usually not a good idea, since this would cause everything you hear to be re-recorded (and possibly cause feedback).
• Some audio hardware models have special routing options, allowing you to send incoming audio directly back to any output. Most likely, you would want to turn these off to avoid feedback.
• No special type of synchronization is required in this system. The sync issues are exactly the same as for a built-in audio system. See the chapter “Optimizing Audio Performance”.
Analog Audio
Digital 2-channel audio (S/PDIF, AES/EBU)
Digital Multi Channel Audio (e.g. ADAT Optical)
Word Clock
This figure shows the same system as in the previous example, but with one addition – digital stereo inputs and outputs. However, the issues listed below also apply to an audio card with stereo analog in/out and stereo digital in/out, or a card with stereo digital in/out only.
Possibilities• The digital output allows you to transfer the stereo output from Cubase VST digitally onto a DAT recorder, for example. Recording digitally this way ensures that no audio quality is lost in the mastering stage.
• In the same way, location recordings made on a DAT recorder (or similar) can be transferred digitally into Cubase VST with no audio quality loss.
• Another advantage is that you are not restricted to the audio hardware’s built-in analog to digital converters - if you have access to external, professional analog to digital converters, these may provide even higher audio quality.
• When making connections for digital audio, make sure you are using the correct type of cabling. Although they often use the same types of connectors, cables for digital and analog audio are not identical. Please ask your dealer for the correct type of cables.
• When recording digitally, it is very important that the digital input of the audio hardware is synchronized to the device producing the S/PDIF signal. This is done in Cubase VST in the Audio System Setup dialog (which you can find in the Audio Setup submenu on the Options menu), by adjusting the Audio Clock Source setting.
• When playing back digitally, it is equally important that the device at the other end of the cable (the DAT in our example) is set to synchronize its digital audio input to the computer audio hardware.
MDR (e.g. ADAT) Analog Mixer Analog Audio
Digital 2-channel audio (S/PDIF, AES/EBU)
Digital Multi Channel Audio (e.g. ADAT Optical)
In this system, audio hardware with ADAT Optical connectors is connected to an MDR, that is, some kind of digital stand-alone recording device (not necessarily an ADAT type tape recorder). No other equipment uses digital audio connections.
Audio input is not included in the diagram above, but would probably happen via the computer audio hardware.In this system, the most straightforward way to set things up is probably this:
• Monitoring of the MDR is done via analog outputs, connected to the analog mixer.
• Monitoring of the audio hardware is also done via analog outputs, connected to the same mixer.
• A digital two way connection is established via the ADAT Optical connectors on the MDR and on the audio hardware. This allows you to transfer data in either direction. The ADAT Optical connection also carries the Word Clock signal.
• This setup allows you to transfer MDR tracks into Cubase VST for editing and processing. Submixes created in Cubase VST can be transferred back to the MDR. If your audio hardware supports ASIO Positioning Protocol, sample accurate transfer is possible (see page 613).
• If the device supports it, you can also use MMC and Tape Tracks in Cubase VST to control the MDR completely from the Cubase VST arrange window. See the separate “Tape Tracks” document.
Only one unit in the system can be the sync master (see the chapter “Synchronization” for more information on sync). There are several options. Which to choose depends on the exact nature of the equipment you are using:
• You can let the MDR be the master. This is the most common choice. This requires that the MDR can provide a clocking signal in a format the audio hardware can read. The Audio Clock Source setting in the Audio System Setup dialog must then also be adjusted accordingly. It also assumes that the MDR can generate MIDI Time code messages, either directly or via additional hardware (a special synchronization device).
• You can let Cubase VST be the sync master. This assumes you can route word clock from the audio hardware in the computer to the MDR. It also assumes the MDR can sync its transport to MIDI Time Code (MTC) messages transmitted from Cubase VST, via the MIDI interface in the computer.
• If you want to use Cubase VST to control the transport of the MDR, MMC is always transmitted from the computer to the MDR, regardless of which unit is the sync master. Again, see the Tape Tracks document for details.
• If your audio hardware and its ASIO driver support ASIO Positioning Protocol, we recommend that you use this, for sample accurate positioning and synchronization (see page 613).
An additional consideration is the choice of sample rates. The audio hardware in the computer must be set to record and play back at the same sample rate as the MDR, or you probably won’t be able to transfer audio recordings between the two.
Finally, just note that it is possible to create audio feedback loops if you feed audio through both the audio hardware and the MDR. Be careful when activating monitoring on the two devices at the same time.
Analog AudioDigital Mixer Digital 2-channel audio (S/PDIF, AES/EBU)
Digital Multi Channel Audio (e.g. ADAT Optical)
Word Clock
All monitoring is done via the mixer which also has analog inputs to record various sources, such as microphones.
Note that the digital mixer may be a part of the audio hardware itself! One example of this is the Yamaha DSP Factory, for which Cubase VST has special support features (see the separate DSP Factory document for details).
Possibilities• All the mixers facilities can be used for setting up the sound when recording. The audio is then transferred digitally to the computer without any loss of quality.
• The mixer’s internal effects and equalization can be used as a complement to those in VST, either when bouncing (see page 516) or during mixdown.
• As with the MDR/Cubase VST setup described above, there must be synchronization between the mixer and the audio hardware in the computer. This can either be done as part of the audio signal or separately.
• In this setup, it would be reasonable to have the mixer slave to the computer audio hardware, instead of vice versa. No time code sync is required, since the mixer doesn’t have a “transport”.
• The note about coherent sample rates throughout the system applies here as well, of course.
This setup is just an expansion on the two above. Any number of MDRs and digital mixers and effect units can be connected to a Cubase VST system. There is even computer audio hardware with more than one digital multitrack connector, allowing you to expand the number of audio channel “buses” in the system.
PossibilitiesThe possibilities in such as system are endless. When recording you can route audio from the mixer to the MDRs or to Cubase. You can route signals to audio effects and bounce tracks via Cubase VST and the MDRs. During mixdown all the recorders can play back and the mixer in Cubase VST can be combined with the external mixer for increased processing possibilities.
ConsiderationsSince this system can be practically anything, it is impossible to say exactly how to “wire” things.
Again, the word clock synchronization needs to be planned carefully. Only one device can be the master and all the others must slave to it. You should also consider using ASIO Positioning Protocol, if your audio hardware and ASIO driver support it.