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. 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. 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. Multi-track audio production The various items of software, and systems made up of software and hardware, that we have described in previous chapters, represent today real ‘advanced working environments’ for sound engineers and musicians all over the world. From the progenitors Digital Performer and Sonar (ex Cakewalk Pro) to the modern Cubase, Logic and ProTools, all these splendid items of software provide, in varying degrees, everything that is necessary to carry out multi-track panning. Often panning is sufficient for applications required by multi-track audio production for video, or for supports like Audio DVD and video games. But X-Spat is the ideal product if sufficiency is not enough. While it maintains the necessary compatibility with traditional panning and with the various necessary encoding algorithms, X-Spat provides more demanding engineers with the most effective psycho-acoustic algorithms to simulate the positioning or the movement of audio sources in any point of a given space. In addition, using the Spatialisation 3D provided by the two DSP of X-Spat as a support or in place of the normal 2D ‘panning’ of the above items of software, the latter will dispose of increased power of calculation for other effects that must use the host computer or the hardware assigned to them. The X-Spat system’s capacity to recalculate all that is necessary to reproduce the same Spatialisation, each time there is a change in the position and the number of speakers used, also creates new possibilities in terms of production if you want to use live multi-track and preserve the original sensations as much as possible, when transferring to a mass-circulation multi-track system, i.e. DVD. Let’s look at some examples of system configuration, also included in the X-Spat Library file of the installation CD-ROM. The file 51ITU_AD_plusExtStereo.xcont2, if loaded in X-Spat Controller and correctly sent to the card, allows you to use inputs 1 to 6 as channels to be spatialized and the couple of inputs 7 and 8 as stereo inputs not spatialized, but directly added to channels L and R of the 5.1. Therefore our output will be a 5.1 ITU made up of a stereo mix and of 5 channels in Spatialisation plus a Subwoofer, always controllable both during the mixing and during the mastering, the ideal solution for the typical recording of music. File Ext51ITUplus7-8Spat.xcont2 instead, if loaded in X-Spat Controller and correctly sent to the card, will allow you to use inputs 1 to 6 as input channels for an external 5.1 premix in 2D panning, and the couple of inputs 7 and 8 as mono channels to be spatialized or as a single stereo channel to be spatialized. Our output this time will be a 5.1 ITU made up of the sum of the signals mixed by an external workstation in panning and by Spatialisation 5.1 ITU of X-Spat. These two examples represent two ideal extremes in a wide range of settings that you will be able to create and memorize in your hard disk at your own pleasure, and will allow you to deal with almost any requirement in multi-track audio production. Live Performance As previously mentioned, the X-Spat system’s capacity to recalculate all that is necessary to reproduce the same Spatialisation each time you change the number and position of your speakers, creates new production possibilities for live use of the multi-track. Therefore the dividing line between production and performance can be made even thinner thanks to Spatialisation, which makes it easier to transfer the spectacular effect of a performance from Live to DVD. However, operative requirements are still an essential factor and they are certainly different in the two working environments. This is another reason why A&G provides two different types of software with the card. The one for live applications is IMEASY X. IMEASY X uses various types of interactive markers to control in real time Spatialisation and MIDI as data transmission protocol, but also as control for each single node of its trajectories. So we recommend the use of this item of software, even as “slave SMPTE” of your favourite application, for your installations or multi-track audio performances. Keep in mind that X-Spat can also simulate the virtual position of one or more audio files, not just their movement. For example, you can successfully simulate the presence of a noise on stage, even if the speakers are installed around the audience. X-Spat considers the speakers as emission points (literally, i.e. as dots: please refer to the central-middle part of the speaker to calculate its positioning). The cabinets can be placed wherever you prefer in the real environment to be spatialized. Theoretically all the speakers could be bunched together! Naturally it’s best to place them around the audience and create two or more levels of positioning at different heights, for a better result with three-dimensional trajectories. We have observed that the most advisable arrangement for live performances, using the basic version of the system in traditional environments like theatres and halls, is as follows: 4 speakers positioned at a height of 1 meter, at the corners of a square and four more in the same positions but 2 or 3 meters higher. This is just a suggestion and you may experiment to find better solutions. Each show or installation is different, but your X-Spat system will adapt to almost any situation. X-Spat inputs can be moved manually in real time, even while play is synchronized to an external SMPTE code. However, you must consider that the tools of the sequencers controlling X-Spat require the use of the mouse, which naturally is two-dimensional. The best solution could be to use an external three-dimensional controller like A&G's ‘TheBat ‘ or to use predetermined trajectories, originally two-dimensional, but modified step by step through the Z parameter. Production of Spatialisation ™ The specific Spatialisation ™ designed for an environment can always be digitally recorded on an ADAT compatible or other similar multi-track recorders. If you are sure that all the parameters of the environment where Spatialisation ™ is being used are invariable, you can leave your X-Spat system in the studio, or pass Spatialisation ™ to others, using a simple multi-track digital support, i.e. an ADAT cassette. Production in Surround ™ X-Spat can also be a very powerful tool for audio post-production of videos, providing new functions that had never been thought of before in Surround ™ productions, such as the use of predetermined three-dimensional trajectories and control via MIDI in real time. Obviously the use of the X-Spat system presupposes the presence of another Dolby certified system to listen and codify in Surround. In this case it will be enough to position the outputs of X-Spat following the standard specifications of the Surround ™ setting. A simple connection of the X-Spat outputs to the Dolby codifier will ensure the direct feedback of the effect resulting from the conversion of Spatialisation ™ into Surround ™.
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