How to resolve AdBlock issue? Fiedler Audio gravitas MDS
Mix bus and mastering dynamics plug-in for multichannel audio
Author: Peter Kaminski
Fiedler Audio is dedicated to audio multichannel technology, and Dolby Atmos in particular. Fiedler Audio has become known for its Dolby Atmos Composer, which is designed to enable simple production and mixing in the Dolby Atmos format. With gravitas MDS (which stands for Mastering Dynamic System), there is now an interesting tool from Fiedler Audio for dynamic multi-channel processing, which has been available since June 2024.
Requirements and installation
gravitas MDS is available as a plug-in for macOS (from version 10.14) and Windows (from version 10) as a VST3 and AAX plug-in as well as an AU plug-in for macOS. It can also be used in the Dolby Atmos Composer and the Dolby Atmos Mastering Console by Fiedler Audio.
You can change the entry in the start menu during the installation process, but it is not possible to select the various plug-in formats. Software licensing is via a license code from the manufacturer, which must be entered after starting the plug-in. Two computers can be activated.
Handling
The gravitas GUI is divided into three sections.
At the top of the screen, you will find the handling of the plug-in presets, undo/redo function, two temporary memories (A/B) to compare settings, and a button for accessing a so-called "Link Editor", which we will discuss later.
The next section displays the signal processing path. Here, you will find virtual level meters at the input and output as well as knobs for the input gain (In Gain) and output gain (Makup), which can also be switched to automatic adjustment using the AUTO button.
The second section offers knobs for the input threshold, the compression ratio, knee transition, and knee range. These parameters can be set separately for the lower and upper thresholds. There are two virtual buttons below the graphical representation of the dynamics processing for switching. When selected below the threshold value, the knobs are displayed in purple and above in yellow, as are the corresponding curves in the characteristic curve graphic. It is also important to understand that both the upper and lower thresholds can be set using the Threshold knob.
To the right of this, a filter (high/low pass) can be setup and, if necessary, deactivated. The cut-off frequencies of the two filters can be set using the mouse. Clicking on one of the two labels below and above the on/off switch opens a dialog for selecting the filter slope between 6 and 36dB/oct. in 6dB steps.
Below these controls, knobs that provide different parameters depending on the input configuration are available. This allows the LFE level(s) to be adjusted. gravitas can also handle multiple LFE channels. In stereo mode, an M/S section appears here instead of the LFE knob (see illustration above). MS processing can also be deactivated, and the side detector and side levels can be changed.
The lower section deals with the detector level and the control variables. There is also a high-pass/low-pass filter in the detector path, which can be set as described in the audio signal path above. The filter settings for the signal and detector path can be linked via the icon on the right below the filter graphic.
To the right, there are knobs for various time constants Attack, Hold, Release and RMS Time. You can also select a preview time (Lock Ahead), which can be linked from the settings via an icon with the RMS time. The preview time naturally has a direct influence on plug-in latency. However, this is not very important in the mastering process.
The 3DET button can also be used to activate three parallel detector settings instead of one, whose detector input gain can then be adjusted using the "Det. Gain" knob. The knobs, or symbolized values, are then reddish, greenish or bluish depending on the selected detector, and the three detector level curves are then also shown in the display, as well as the two threshold values set in the signal path.
The Input Configuration dialog can be accessed via the icon below the input bar graph meter. The individual channels for dynamic processing are activated via the input selector at the bottom. If a channel is not selected here, then it is set to bypass mode. In the upper area, the input signals can be routed to the detector channel via a mixer, and the level can be adjusted. The "Listen" button can be used to listen to the output of the mixer or the input of the virtual detector stage.
Another special feature of gravitas is "Parameter Linking". If several gravitas instances are used in a project, parameters can be linked across instances. To realize this, one or more link groups are created, and the respective instances are assigned to a group. Which parameters are linked in a group can be determined via the parameter list by simply selecting the desired parameters.
In practice
We tested version 1.0.2 of gravitas MDS on an AudioKern B14 workstation from Digital Audio Service under Windows 11. We used the plug-in version (VST3) in Steinberg’s Nuendo 13. Of course, the plug-in requires a lot of resources; however, for a modern DAW computer, it works without any problems. We used several gravitas in busses or beds and had no resource problems.
Depending on the host software and plug-in, up to 128 channels can be processed, for example, in Reaper. With Nuendo as a VST3 plug-in, the maximum number of channels is 64. Another feature worth mentioning is the use of the module in Fiedler Audio's Dolby Atmos Composer. This means that up to 128 channels of an entire Dolby Atmos mix can be edited using gravitas MDS.
gravitas MDS is a plug-in that also appeals to specialists. There is currently no alternative to gravitas MDS in the multichannel sector that offers such a comprehensive range of threshold and detector settings. It is one of the most flexible dynamic tools for multi-channel operation, especially when it comes to multi-channel mastering. gravitas is not only multi-channel-capable, but also functionally specially adapted to the needs of multi-channel productions. This is underlined, for example, by the flexible detector mixer in the Input Configuration dialog.
However, not all aspects of gravitas are self-explanatory. There are several demo videos on the Fiedler Audio YouTube channel that explain the function in detail and a manual is available as a PDF.
gravitas MDS is a product that belongs in the hands of experts if you wish to use the full functionality ofthis plug-in. The results are absolutely convincing both in the area where you want to make slight corrections as well as with extreme interventions in the dynamic range, for example, with drums and percussion.
Conclusion
gravitas MDS costs approximately 300 euros. This includes the plug-ins and the activation for integrated use in Dolby Atmos Composer and as a module in the Mastering Console.
gravitas MDS offers what many multi-channel-capable plug-ins lack. It is not enough to simply increase the number of channels in a dynamics tool to ensure practical use in a multichannel production environment. This is where gravitas MDS is one step ahead of its features.