Nov 13, 2018

Custom Speaker Configuration in the Spat Revolution Immersive Audio Engine


A blog read by Hugo Larin, Business Development for Spat Revolution

When you find yourself working on a custom multi-channel speaker arrangement, the Speaker Configuration editor is where a model of the sound diffusion system can be defined and stored into the list of speaker configuration presets. From the below image you can see that the current config (a system predefined config) can be, a Duplicate (a copy will be generated for editing) or a New config can be created.

Figure 1: The speaker configuration window showing a pre-defined 13.1 Auro 3D speaker arrangement

Managing the Speaker Configuration includes the ability to delete a config, rename a config, export configuration(s) to a file, or import configuration(s) from a file. Note that Spat Revolution’s pre-defined speaker arrangements can’t be deleted or renamed, but duplicating them (making a copy) will allow you to edit the arrangement thus starting from an existing configuration. The Normalize feature is there to rapidly scale down the speaker arrangement to have the furthest away speaker distance set to 2M only. This helps reduce the virtual room environment size to facilitate working with the parameters range when working with very large speaker setups.  

Figure 2: Editing a speaker configuration showing a copy of a 13.1 Auro 3D speaker arrangement

Once editing a speaker configuration, you can either + Add, – Del, Move Up or Move Down speakers in the list. Note that the total number of channels in your arrangement is denoted above the list. Your speaker system contains a Low Frequency LFE channel where you want the ability to send audio to it like on an aux system? Simply adding a channel (or channels), called LFE, will do the magic for you here directly. This particular channel won’t be fed from the virtual room panning, but by the LFE Send on each of the sources that will be available on rooms containing an LFE. Obviously without the room reverberation.

Speaker Position

Position information of the loudspeaker can be entered as X, Y, Z in meters or with Azimuth degree, Elevation degree and Distance in meters. Delay and Gain can be used to manually align the physical speaker location to a virtual one, essentially creating a virtual speaker.

Wondering what the Compute and Reset is all about? Spat Revolution can use the measurements you put into that speaker arrangement to calculate (and apply) the delays and gains for rendering spatial audio on a speaker physical configuration that may not have speakers located in ideal locations. This is a technique preconized when using panning methods that are sweet spot centric such as VBAP and VBIP. The methods will provide very smooth panning on arrangements that have all speaker equidistant to the optimum listening position. So this is what the compute will do for you when desired and using such panning method. You don’t need to move the speakers, Compute the delays and gain for optimal panning experience. Note that it is preferable to do this in Spat Revolution instead of external processing as Spat will use the computed speaker locations (the virtual speakers) for actually spatializing afterward. This is an advanced speaker management technique made easily accessible by a single press of the Compute Speaker Alignment button.

In some cases, creating speaker setups in an editor is not the most efficient way, primarily when such information is available as a list and was exported by an acoustic and design simulation software like those used with loudspeaker companies. So the speaker config work was already done onced. Although an advanced technique to be used with precaution, a Custom Speaker Arrangement file template is available from the Flux:: Support team that can allow you to enter your Speaker arrangement configuration along with the different speakers location in it. This methods allows to input speaker configuration (FromCartesian) raw data, Polar (FromSpherical) data, or by creating speaker layers with specific angles. All this can be quite practical for some larger more complex setups.

Spatially Yours!

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