In the filter section we realized that real innovation lies not in meticulously recreating the ultimate sound of some legendary synth of the past. We leave that to other synth constructors, who are probably far better in this domain. These (virtual) analog legend synths truly are legendary, no doubt about that. But the future has to create new legends in order to stay interesting.
When creating digital filter algorithms, there is much more possible than only recreating resonant lowpass filters. Literally thousands of other combinations of peaks and holes in the frequency response curves of digital filters are possible. We soon found out that a decent and easy-to-use hands-on formant filter is a very rewarding sound sculpting tool. It took us some time, but we created a three-vowel morphing formant filter, with 10 preset 'vowels' or formant combinations to choose from, and the possibility to user-adapt these presets or create whole new formant combinations.
formantfilter.mp3 // An example of the formant filter acting on a sawtooth wave, and next mixed parallel to a resonant hipass, playing some chords.
So what is a formant filter? Look at it as a number of bandpass filters working in parallel on a sound. Every bandpass filter enhances a small frequency band out of the sound. Certain combinations of bandpass frequencies sound like the vowels of the human voice. For example: with bandpass frequencies around 800Hz, 1200Hz and 2800Hz, it starts sounding like and 'A'.
On Modor's Formant Filter, you can put 3 of those 'vowels' (bandpass frequency combinations) behind the full left, center and full right positions of the Formant knob, allowing to morph between vowels. And this morphing can be taken literally, it is not a crossfade between different vowels, but the actual bandpass frequencies shifting from one position to another.
Of course we also gave the Modor NF-1 a classic resonant filter. It can be used apart from, or in combination with the formant filter. We made a simple but decent 12dB/oct resonant filter selectable as lowpass, hipass, bandpass and bandstop. It's resonance goes up to self-oscillation, and the filter's exit can be driven into distortion.
filterex.mp3 // A little playing around with the lowpass filter, into self oscillation and adding some output drive.