wind, rain, and thunder
vsti by xoxos


thunder uses filtered delay networks to model the reflection of sound between the clouds and the ground.

acoustically, high transients travel faster and for less distance, so thunder appears to drop in pitch as the lower frequencies are delayed more.

it is unfeasible to accurately model the reflections and caustics of a lightning column, so subtractive synthesis is applied.

lowpassed noise is passed into a delay line before being routed to the delay networks. the delay line is modulated by a noise source, which creates 'folding' caustics i associate with thunder.

for musical use, an exponential 'strike' envelope is controlled by key velocity.

noise freq is the main performance parameter. mod wheel and pitch bend are both routed directly to it.

height 1 and height 2 control the longest distance of each delay bank, between 10 and 2000 feet. the random seed value determines the lengths of other delays, and the stereo positioning.

speed smooths the transition between values when the seed control is changed.

the farenheit control accurately tunes the delay lengths as a function of ambient temperature, however due to the overall abstraction of the model, it's function is essentially ornamental.


rain uses two sine oscillators which are randomly triggered and modulated. several parameters include a variation width control.

the second oscillator's amp decay is set from 0 to the same as the first oscillator. it can also be detuned to create an attack sound.

unlike most synths, the pitch envelope creates a rising pitch which may remind you of water.

a resonant low pass filter adds definition to the patch.

pitch bend is applied to rate and mod wheel is routed to volume.

pops and clicks occur when a new event cuts off the previous one. the same effect is produced by rapid panning.

rain is designed to be low on cpu, so these amplitude modulation artifacts are accepted, or exploited. lower rate triggering reduces artifacts and can be used in conjunction with polyphony to reduce transients.

multiple instances create a more dynamic environment, as each patch generally describes one area or surface.

some other uses for this vsti are demonstrated in the presets.


wind is four band pass filters effecting white noise in parallel. the filter paths are modeled to describe resonances within the acoustic space.

the first modulation is applied with separate trimmers to the cutoff of all four band passes. this creates a general rise and fall reflected in each band at a different energy level.

the individual caustics of each resonance are produced by a bank of four modulators running at the same rate. high caustics settings describe higher energy levels and more complex environments.

after the filters, a similar bank of four modulators amplify each band.

pan locations are produced by the seed value. the var button selects whether each band should stay in the same position or shift to a new pan location with each new note.

pitch bend is routable to several "pitch/intensity" destinations and mod wheel is routed to "force" coefficients.

wind is a compact solution for dense or subtle environmental effects.

made with synthedit

these vsti make extensive use of technology created by chris kerry