Physical modelling is one of the most fascinating techniques in the modern synthesist's arsenal. By using complex algorithms to simulate the acoustic properties of physical objects, the process enables us to design authentic-sounding recreations of existing instruments, or create imaginary ones that could never exist in the real world.
There is no shortage of excellent physical modelling synthesizers on the market: AAS Chromaphone, Baby Audio Atoms and Physical Audio Modus, to name just a few. (In fact, if you own Ableton Live Suite or Logic Pro, you've already got one in your DAW.) But if you're looking to experiment with modelled sounds without dropping any cash, developer TiagoLr has released an open-source physical modelling synth plugin that you can download absolutely free: RipplerX.
At the core of RipplerX are two resonators that can be routed independently in parallel, or in series, so that the sound of one resonator influences the other. Using a technique called modal synthesis, these resonators simulate how physical objects vibrate when struck or excited, mimicking the sound that's produced when you take a bow to a violin's string, or beat a drum with a drumstick.
RipplerX offers nine different models of acoustic resonators, or modelled physical objects.. The list includes simulations of a string that can be bowed or plucked, percussive objects like a beam, drumhead and marimba that can be struck, and models of tubes that generate sound by the intake of air, as you would a flute or clarinet.
Each resonator can be excited, or triggered, via two different input sources equipped with an ADSR envelope: a mallet generator that simulates a percussive strike, or a noise generator that provides a continuous excitation, like a bowed or wind instrument. The character of each resonator can be further shaped using several additional controls for inharmonicity, tone and material, along with envelope controls and a high-pass filter.
RipplerX is based on two existing synths: Sai'ke Partials, an open-source modal synth, and an early version of AAS Chromaphone, one of the best-known physical modelling synth plugins. The developer notes that Chromaphone is a "more complete synth" with additional features, and urges those that find RipplerX useful to check it out if they want to dive deeper into physical modelling.
RipplerX is available now for macOS, Windows and Linux in VST3, AU and LV formats. Head over to TiagoLr's GitHub page to find out more or download the plugin.
