The V4 Tracking Engine is the software at the heart of Stagetracker FX and is where all aspects of system setup, audio setup, performer tracking, audio localisation and system monitoring are carried out.
Many of these previously complex procedures are now done automatically by the V4 Tracking Engine.
RadioEye setup is now almost entirely automated, requiring the user only to enter the physical height of the unit from the stage floor. The procedure of allocating TurboTags to the system is now also under software control.
Sound system setup and audio localisation are achieved using the Master and Point Mixers. The mixers present the user with a simple, familiar interface, enabling them to control and adjust speaker configurations in an intuitive working environment.
Using the mixers, the user has complete control over the level, delay and EQ of all speakers in the sound system, allowing precise localisation to be achieved. Speaker groups may be created and controlled using familiar VCA level masters, group delay, mute and solo functions. Unique "on-the-fly" temporary output groups can be created; allowing any combination of speakers to be adjusted together without the need to create a new master group.
The V4 Tracking Engine features a new Automatic mode which automatically generates a set of Points on the Tracking Layer and assigns and time-aligns speakers to these Points. Automatic Mode is perfect for touring productions and also provides a good starting point for users wishing to create their own audio setups.
Tag signal transmission strength, battery status, data packet quality and tracking performance are all monitored in real time on informative graphs and plots. The V4 Tracking Engine can set tracking filters automatically for optimum tracking performance. It is a simple matter for the user to adjust these filters on a single TurboTag or globally on all Tags, should they wish to do so.
The V4 Tracking Engine may be used online or offline, enabling the user to configure a complete show setup in advance or to edit a show while away from the Stagetracker FX system.
V4 also interfaces with the Effects Engine in Stagetracker FX to achieve advanced localisation and surround effects for performers' voices and sound files.
The 3D user interface reproduces the real time movements of the on stage performers on the computer screen. Tracking data may be recorded in V4 and used for system performance evaluation.
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Each performer or object to be tracked carries a lightweight, matchbox sized, radio transmitting TurboTag. As the performer moves around the stage, the position of the Tag is continuously tracked by the intelligent RadioEye mounted above the stage. The RadioEye sends raw positional information via a standard CAT 5 cable to the V4 Tracking Engine where proprietary filtering algorithms are implemented to produce on-stage positions for the Tag.
The V4 Tracking Engine provides real time tracking information to the user and intuitive filters may be adjusted by the user or automatically set to achieve optimal tracking performance. The processed positional information is then sent to the Stagetracker FX audio matrix.
In order for a performer's voice or a sound effect to follow the movement of a Tag, the audio signal is sent from the mixing console to an input on the audio matrix. This matrix input is then assigned to a TurboTag in V4 software.
As a performer moves on stage, their associated Tag is carried through and between user defined Points, created on the Tracking Layer in the V4 Tracking Engine. The parameters contained in the relevant Points are then applied to the performer's audio signal in the Stagetracker FX audio matrix.
The result is that the voice of each performer follows them as they move on stage, bringing a new level of realism to the performance.
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Until now, all audio localisation systems have been setup using a similar principle. - Divide the stage area into defined areas or "zones" and then time align all the speakers in the house to the centres of each of these zones.
This method was devised before real time performer tracking became a reality, and was designed for localisation of audio in static positions. However, when the same method was used for localisation of moving audio sources, such as performers, serious drawbacks arose and it was clear that a new approach was required.
V4 - A new approach to audio localisation
With the release of the V4 Tracking Engine, audio localisation has been approached differently, with the emphasis being to achieve effective audio localisation quickly and to move audio smoothly and naturally on stage.
For many years, creative sound technicians have been achieving audio localisation manually by panning audio sources between speakers in the left/right direction and adding or subtracting delay in the upstage/downstage direction.
The V4 Tracking Engine adopts this familiar method, but automates it and builds upon it by introducing a powerful new concept.
- Traditionally, audio has been panned between speakers. The V4 Tracking Engine pans between Points.
A Point in the V4 Tracking Engine is a user definable virtual object which has an active effect on audio. Any combination of speakers, at any desired level or delay setting may be assigned to a Point using the Point Mixer, and these settings will be applied to any audio source entering the active area of the Point. Speaker relationships created within Points may be as simple or as complex as the user requires.
In addition to Points, the V4 Tracking Engine introduces innovative tools such as Layers, Borders, and Active and Passive Zones. Using these tools, audio setups can be tailored to meet the exact requirements of the venue or the production.
The Tracking and Effects Layers generally represent the onstage and offstage areas of the theatre. Points are placed on these layers which can relate to actual physical positions in the venue. Localisation of an audio source is achieved by time alignment of the speakers contained in the Point to these physical positions. Effects speakers, such as surround speakers, may be assigned to Points on the Effects Layer, allowing voices or sound effects to be placed or moved anywhere in the theatre for a full surround sound experience.
Localisation of audio sources is achieved by time aligning the speakers contained in Points to physical locations and impressive effects can be achieved.
For example, by adding increasing amounts of delay to Points placed "upstage" on the Tracking Layer, a realistic sense of depth is achieved as performers move through Points from the front to the back of the stage. This feeling of depth can be enhanced even further by attenuating audio level on the upstage Points.
A unique Width Control allows the user to vary total pan width from the front to the back of the stage and even to pan audio sources asymmetrically.
By placing borders around Points, the size and characteristics of the active area around a Point can be radically altered to suit the requirements of a production. For example, the stage could be configured to allow smooth audio movement everywhere except at a specific location. The user may wish to define a zone at this location in order to achieve a special effect, such as creating a mute zone. In this case, any audio source entering the zone will be muted and remain muted until the zone is left.
The V4 Tracking Engine gives the user complete control over audio management. However, V4 goes even further and introduces a revolutionary new setup method - Automatic Mode.
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Automatic mode has been designed to allow sound engineers to achieve effective audio localisation over the entire stage area quickly and with only a few mouse clicks. On-stage Points, depth delay calculations and upstage audio level attenuation are all calculated and entered automatically by the software.
In Automatic mode, the user has the option to simply choose a PA configuration (Stereo or L,C,R). The V4 Tracking Engine will then automatically assign audio matrix outputs to the relevant number of Points on the front line of the stage and delay the speakers connected to the matrix outputs to these physical positions.
Subsequent upstage Points are then generated, automatically calculating and adding the necessary speaker delay values. Audio levels are automatically attenuated by a user defined amount in the upstage direction. Stage size, system latency, Haas precedence effect and positive or negative distance from the PA to the stage front are all taken into account by the software when calculating Point level and delay values.
Front fills, out fills or balcony delays may be added to the system as required and V4 will automatically calculate and enter the necessary level and delay values relating to the upstage Points for these speakers. The user is free to add, remove or adjust speaker settings at any time and V4 will make automatic adjustments accordingly.
Up and downstage pan width and attenuation can be varied or fine-tuned as required.
Automatic mode is extremely effective for achieving audio localisation in a matter of seconds. It should also be noted that the procedures used by Automatic mode are optimum for localising audio when using long throw, wide coverage PA system such as line arrays.
Automatic mode is only available for Points created on the Tracking Layer.
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The unnatural, "jumpy" audio, associated with the traditional Zone method of setting up localisation systems (see below), has been erradicated in the V4 Tracking Engine. Audio is now moved as you would expect it to be moved - smoothly, continuously and naturally.
Beyond conventional panning
The use of Points means that many of the drawbacks of conventional volume panning can now be effectively overcome.
For example, "out fill" or balcony speakers on one side of the theatre may be assigned and time aligned to Points on the far side of the stage. As a performer walks towards the opposite stage side, the delayed speakers will be gradually increased in volume. If the Haas precedence effect has been used when time aligning the speakers, the delayed speakers will be imperceptible to the audience. They will continue to hear the performer clearly, even though their voice will appear to originate from the opposite side of the stage.
V4 provides the creative sound designer with new and unique possibilities for achieving effective localisation while ensuring perfect audience coverage.
Zone setup in the V4 Tracking Engine
Despite the drawbacks associated with using a Zoned audio setup, there are a few special situations where it may still be a viable option for achieving audio localisation. For example, when shows are performed "in the round."
For these reasons, and for current Stagetracker FX users who wish to upgrade to V4 but retain their current zoned audio settings, Zone setup is accessible and supported in the V4 Tracking Engine and choosing the "Create Grid" option will provide a useful and flexible starting point.
Note that specialist training is advised to achieve acceptable results when using a Zone setup.
Drawbacks of Zone mode
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