Equalizers will never be the same again.

Ultimate Sound Quality
▬ Robust Nyquist-matched Transform
Through originally developed "Robust Nyquist-matched Transform", Kirchhoff-EQ has made digital-domain frequency response more approximate to its analogue counterparts without high frequency cramping as in regular IIR (infinite impulse response) equalizers. This technique is applied on all filter types in Kirchhoff-EQ.

▬ High-Precision Processing
64-bits is mandatory and it's not negotiable. The internal processing of Kirchhoff-EQ is always in 64-bits (or 117-bits), regardless of host DAW's current working precision.
Psychoacoustic Adaptive Filter Topologies

All linear filter structures should have the same sound on paper. However in real-world application, round-off errors make every filter structure sound differently: some better in low frequencies, some better in high frequencies.

A technology called "Psychoacoustic Adaptive Filter Topologies" has been deployed in Kirchhoff-EQ. Filter structures change themselves to a "best fitting" state along with corresponding band frequency changes, resulting in optimized sound quality in both low and high frequencies.

▬ Switchable Ultra-High 117-bits Processing
Since there's already 64-bits, why not go further? Kirchhoff-EQ uses a technique called "Double-Double" to make precision of internal processing reach 117 bits! This is the first equalizer in the world to reach such precision. You can switch between 64-bits and 117-bits at any time. It satisfies the most demanding ears.

* Linear-phase mode always uses 64-bits as it is an FIR(finite impulse response) filter, and does not support 117-bits.

▬ Filter Types
15 Unique Filter Types

low pass, high pass, band pass: continuously variable from 0 dB/oct to 96 dB/oct;
bell, notch: continuously variable from 12 dB/oct to 96 dB/oct;
low shelf, high shelf, tilt shelf: continuously variable from 6 dB/oct to 96 dB/oct;
flat tilt and flat top;
sword: has sharper slope than bell, specifically designed to "dig" out resonances.
brickwall low pass, brickwall high pass, allpass low and allpass high.

▬ Continuously variable slopes Filters
The slope of most filter types can be continuously changed from 0 dB/oct, 6 dB/oct or 12 dB/oct up to 96 dB/oct. Would you like to try a 8.125 dB/oct highpass?

32 Filter Types Modeled from Historic Vintage EQs!

Get vintage and modern at same time! We modeled 9 vintage EQ hardware units as a total of 32 EQ types implemented in Kirchhoff-EQ. Benefit from Robust Nyquist-Matched Transform, every EQ type precisely matches the original hardware and won't cramp near Nyquist frequency. For a further step, unlike the original hardware that only allows to choose between several frequency positions, we modified the DSP model to make adjustable frequency points for all these types! Every type in these models can be used together with regular EQ types or other modeled types, and can be applied with dynamic functions (except lowpass and highpass types). This brings you more freedom and convenient operations.

* No non-linear behaviors were modeled. All vintage filter types only contain ideal linear parts of their physical model.

▬ Zero-Latency/Analogue/Linear/Mixed Phase Modes
The phase mode of Kirchhoff-EQ is switchable between zero-latency mode, analogue mode, linear phase mode and mixed phase mode, in order to meet all your phase relationship needs.

* No matter which phase mode currently in, if dynamic functions is turned on for a filter band, it will work on minimum-phase mode (won't affect other bands).

▬ Mixed Phase Mode
The zero-latency and linear phase modes have a very different sound. Kirchhoff-EQ provides a mixed mode that uses zero-latency when the band frequency point is low, and uses linear phase when it is high. Each band could be changed smoothly between minimum and linear phase mode according to their frequency.

* There is no noticeable crossover between filter types while in mixed phase mode, transition is seamless.

▬ Flexible Dynamic EQ Functions
Dynamic functions in Kirchhoff-EQ are not just a bonus, they provide the richest functions you have ever seen. Enabling you to achieve unlimited possibilities of dynamic EQ functions. All filter types (except low/high pass, band pass and notch), even these vintage-modeled ones, can be applied with dynamic functions.

▬ Harmonic Shifted Envelope
All dynamic EQ have odd- and non-integral harmonics, that’s the laws of physics. By using advanced DSP techniques, Kirchhoff-EQ now "shifts" most energy of odd-harmonics into even-harmonics, creating an ultra-low noise floor and enhanced sound. Now you can use dynamic functions with freedom without worrying about smashing your sounds.

▬ Two-Way Threshold
You can now control how dynamics react to the portion of the signal above/below threshold concurrently. In Kirchhoff-EQ, the "Above" stage works as a compressor or upward-expander, and the "Below" stage works as an expander or upward-compressor. For example, you can raise the signal below the threshold AND compress the signal above the threshold to "stabilize" a band.

▬ Detect/Relative Envelope Detection
Let us imagine a simple case: we are playing an audio clip in which sounds around 1khz are 9 dB. You may think "The 1khz range is over powering, We should reduce at 1khz." But we should also consider the overall level. If the whole audio is 30 dB, you would not feel that 1khz is too much, instead you may feel it's not enough. The better criteria to determine whether a band's volume is high or low is its relative portion in overall volume envelope, instead of only its absolute dB value.

Thereby we introduce "Detect/Relative Envelope Detection" in Kirchhoff-EQ. The dynamics are affected by both current frequency band and relative portion to a "Relative" band. The contribution of Relative Envelope Detection to dynamics is also adjustable: when set to 0%, it degrades as a normal dynamic EQ; and when set to 100%, the amount of dynamics is fully calculated from the relative portion.

The “detect” band is set according to the frequency and Q of the band by default, “Relative” is the whole audio envelope by default. But they can be set freely.

The detecting band and relative band have a freely adjustable frequency point and Q value. Or enable “S.C.” mode to use “Detect” or “Relative” with a sidechain signal.

▬ Onsets Detection Mix
By turning on "Onsets" mix, the envelope detector reacts more specifically to transients inside of the envelope. So you can fine-tune the tone of transients. For better adjustability, you can "mix" envelope detector and onsets detector. For example, you can compress the high frequencies just a little bit whilst compressing the sudden increase of high frequencies more aggressively.

home page: https://www.threebodytech.com/en/products/kirchhoffeq

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