It is often found that artificial reverb effects use some combination of echoes with short delay times to recreate the acoustics of a particular space. By introducing enhanced harmonics of the input signal during the reverberation process we can create a shimmering effect. One such example of this would be to use real-time pitch shifting with feedback delay to acquire said harmonics.
Instead of using the shimmer reverb VSTs downloaded on my computer, I set about trying to recreate it myself, using Ableton’s stock plugins. Drawing up an Audio Effect Rack, I created an effects chain. It consisted of a Reverb, Grain Delay, Ping Pong Delay and another Reverb, in that order, as the distillation of ingredients in a shimmer effect is the combination of a sound diffusing (Reverb) whilst the resulting diffusion shifts in pitch (Grain Delay). I further spread this diffusion out with the following reverb and some slight delay.
Firstly, bypassing the first instance of Reverb, I went about setting the frequency of the Grain Delay to about 5Hz, taking the pitch all the way up to 12, and leaving its random pitch and feedback setting to 0. I altered the dry/wet mix to 75 percent and unchecked the sync box, allowing me to set the delay time all the way up to 128ms.
Turning the first Reverb back on, I increased it’s size and also the decay time to about 10 seconds. After applying some input processing by cutting out a little bit of the lows I brought the modulation speed up to just above 1Hz in early reflections. I then increased the volume of the diffuse slightly, all of which made the Grain Delay’s pitch shifting a little less prominent in the mix. The Ping Pong Delay, just after the Grain Delay also helped spread things out in the stereo field, so that nothing about the resulting shimmer effect was too centred, in order to achieve the appropriate ambience, allowing it to flourish in the background. Using another instance of Reverb at the end of the effects chain, with similar processing to the the one that preceded it, I continued to tweak settings, such as the feedback, in order to explore and apply more characteristics to the shimmer, aiming for a ethereal, cavernous feel.