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Suggestions for a correct usage of the X-Spat system
The X-Spat system is a versatile and powerful resource for a wide range of applications, even if its natural 'habitat ' is multichannel audio production, from surround to 'Live 'performance. This chapter provides the necessary information to use the system correctly in some applications, including surround 5.1 and 7.1.
The X-Spat Diagram window
Select X-Spat Diagram in the A&G X-Spat> menu or File >Diagram from the only menu in the Patch bay window, to visualize a flow diagram, which we hope may be useful to dispel possible doubts relating to the configuration of the X-Spat internal patchbay.
Some preliminary considerations: the Patch bay area, with its 34 inputs and 56 outputs, to the left of the diagram, allows the routing of incoming audio signals to any of the available outputs. For instance:
The eight “to HOST” outputs correspond to the eight firewire channels inputting the computer. The eight channels outputting the “Spatialisation Matrix', either mixed with the “Insert Returns” or not, can also be directed to the “to HOST” outputs for a possible codification of the Spatialisation in one of the multi-channel encoding formats.
The 8 input channel strip correspond to the 8 inputs of Spatializer and its 8 outputs can be connected to the 8 direct 'to ROSETTA Option IN' outputs, which correspond to the analogical or digital Rosetta/800 96 outputs.
The 'Number of Speakers' parameter of the area 'Global Settings' can be set to a value equal or inferior to 8, and, to actuate a set-up 5.1, this value must be equal to 5. The channel reserved to the subwoofer could be output 4 of 'to Rosetta Option In', connected to 'Send/Out' of the 'Sub Mix A'. The Sub Mix A could receive as inputs the 8 channels coming from the host or from 'Rosetta Option OUT' itself. This would provide a separate non-Spatialized channel, which would be the result of the mix of all the incoming audio sources that are already spatialized through the Spatialisation Matrix. The 16 'Channel Inserts' can also be used in a similar way in order to have as many separate channels that can be assigned to any 'physical' output.
There are also 8 test signals, (really 7 as the condition 'No Signal' must also be selectable). It's advisable to connect any non-used patch bay input to 'No Signal'. Watch out for possible signal feedbacks, which may happen in the host computer software used. X-Spat's patch bay is very versatile and powerful and we have tried to eliminate all possible 'dangerous' configurations. However, we can°òt do anything to avoid wrong external connections.
Common factors to be considered for all applications
Spatialisation ™ is the result of the sum of all the speaker outputs. If one of the speakers doesn't work properly or is in mute, we advice you to change the number of output speakers through the parameter in the 'Global Settings' area of the X-Spat Controller software.
In order to get the best possible effect, set correctly the position of the spatializer's outputs and control that these outputs are correctly assigned to the Rosetta 800 outputs in the Patch Bay of X-Spat Controller.
For example, in a 5.1 ITU set up, the number of outputs of the spatializer must be set to the value 5, through the “Number of Spat.Outs” parameter in the “Global Settings” area of X-Spat Controller. However the ITU standard provides that the subwoofer should be connected to channel 4 of the Rosetta. Therefore, in the Patch bay window, we will connect output 4 of the Spatialiser to output 5 of the Rosetta and output 5 of the Spatializer to output 6 of the Rosetta. Output 4 of the Rosetta, destined to the Subwoofer, can be directly connected to one or more inputs or to one of the internal submixers of X-Spat.
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In practice always consider that:
each output of the X-Spat spatializer can use any of the outputs of the Rosetta 800;
the price to pay in order to take advantage of this versatile and convenient option is the extra attention we need to pay while setting the internal patch bay of X-Spat.
For the playback from DVD, it's much easier to encode the audio file produced by X-Spat in AC3 or DTS. Connect the outputs of the Rosetta 800, whether they are digital or analog, to a multi-track recording system on hard disk. Record your Spatialisation and then load the resulting audio files in one of the many encoders available on the market, like A.Pack or similar.
It's worth noting the behaviour of Cubase SX for Mac OS X in this situation. The Steinberg audio sequencer allows the creation of a virtual multi-track bus which accepts the Firewire Host In channels of X-Spat as input and the internal hard disk as destination, independently from the fact that the Host Out Firewire channels of the card are used at the same time as outputs from Cubase SX to X-Spat itself. An X-Spat Base bundle and a Powerbook with Cubase SX and A.Pack will be sufficient for the production and mastering of multi-track projects onto DVD. |
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