HoRNet ThirtyOne MK2 [WiN]

Publisher: HoRNet
Product: ThirtyOne MK2
Version: 2.1.0-TeamFuCK
Format: VST2/VST3
  • Publisher: HoRNet
  • Product: ThirtyOne MK2
  • Version: 2.1.0-TeamFuCK
  • Format: VST2/VST3

ThirtyOne MK2 is a plugin that includes a spectrum analyzer and a graphic equalizer, both have the standard 31 one third octave bands.

This pair of tools is very common in every rack of any live mixer as the final tool in the master bus, for this reason we decided to recreate the behaviour and specific time response of a very common Italian analog spectrum analyzer.

The equalizer is also inspired by analog units allowing ThirtyOne to recreate that master chain feeling that you are used to.

We put a great care in recreating the smooth lighting of LEDs driven by a smoothly increasing current flow, each column of twelve LEDs comes after a 20dB/octave filter (like the original hardware unit) and it’s response speed is selectable between 0.25, 1 or 4 seconds allowing you to see both fast peaks and average frequency level.

Each of the LED of the bar can have a value of 1, 2 or 3 dBs (like in the original hardware unit) and we also added 6dB/LED option, when changing the resolution the scale on the left of the LED display updates accordingly.

We also added a maximum peak hold LED for each frequency band that can be enabled or disabled that the original unit did not have.

Right below the spectrum analyzer we have put the 31 sliders that will let you shape the output and fix any particular resonance. Each of the sliders drives a standard 1/3 octave second order filter and can be adjusted from -15 to +15 dB, you can also change the value for each band typing in the box below each slider.

The equalizer has a very special feature called the “Auto EQ”, when enabled the output of the spectrum analyzer is used to tune the gain for each of the EQ band allowing the equalizer to automatic set itself so that the maximum harmonic balance is achieved.

ThirtyOne MK2 provides three different “Auto EQ” algorithms: Average, Median and Lucky, the first two are based on some mathematical models while the third one is a lucky mistake and we decided to keep it because it sounded good 😀

“Auto EQ” is linked to the frequency analyzer output so changing the analysis speed affects the algorithm, using the 0.25s changes the equalization very fast and allows you to track also the fast frequency spikes, while using the 4s setting works more on the average frequency content.

To tune the “Auto EQ” output you can use what we call a “compensation curve” which is an offset that it’s applied to every level computed by the “Auto EQ”, so if you think that the resulting eq curve it’s too extreme in some band you can correct it using the “custom” setting of the compensation curve. If you find a compensation curve that you like you can export it and then load it in other projects using the “load” and “save” buttons.

The resulting EQ curve can be decreased or increased using the “EQ Amount” knob that scales every gain computed by the “Auto EQ” algorithm by a fixed value and allows you to increase or reduce the level of each band while maintaining the same ratio between them.


  • 31, one third octave, spectrum analyzer bands.
  • Spectrum analyzer carefully crafted to give you the feeling of analog hardware units.
  • three different integration times for the analyzer.
  • four scale ranges for the analyzer.
  • peak hold display.
  • display both the L+R (mid) component or the L-R(side) component of the audio spectrum.
  • 31, one third octave, equalizer.
  • Each band of the equalizer can be bypassed.
  • Each band of the equalizer can be put in solo mode.
  • Each band of the equalizer can be disabled for the AutoEQ.
  • Each band gain adjustable from -15 to +15 dBs.
  • “Auto EQ” automatically balances frequency content.
  • Three different algorithms for AutoEQ.
  • AutoEQ can work both in continuous or fixed mode.
  • Each of the two modules can be disabled to save CPU.
  • AutoEQ amount knob to scale the effect impact
  • Custom compensation EQ profile for the AutoEQ algorithm
  • Compensation curve can be saved and loaded
  • Preset save and load
  • Bypass button for the equalizer.
  • GUI is scalable and hardware accelerated.
  • macOS (>=10.11, Metal required) and Windows (Windows 7 and later, OpenGL 2.1 required) support.
  • Apple M1 support
  • 64-bit plugin for Mac and Windows.
  • Audio Units VST2.4, VST3 and AAX format.

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