Concentric
Overview
Concentric is a matrix effect that creates expanding and contracting rings from the center of the matrix.
It is audio reactive, using a selectable audio band-pass filter to control the speed of the rings’ motion.
Here’s an example with a 64x64 matrix & an 256x256 matrix:
Presets
RESET — Rainbow gradient; rings expand at a moderate speed.
OCEAN IMPLOSION — Blue-green gradient; rings contract.
FIRE EXPLOSION — Red-orange gradient; rings expand rapidly.
RAINBOW EXPLOSION — Fast rainbow gradient; rings expand rapidly.
Settings
The Concentric effect includes a few controls:

Rotate — Rotates the effect by 90° for every unit.
Brightness — Self-explanatory.
Concentric effect specific settings:
Gradient — Gradient used for rings.
Frequency Range — Selects which audio band-pass filter controls the speed of the rings’ motion.
Invert — If enabled, makes rings contract instead of expand.
Speed Multiplier — Factor by which the power of the frequency band is multiplied. (Higher = faster.)
Gradient Scale — Scales the gradient across the matrix. (Higher, less repetitions.)
Stretch Height — Stretches the rings vertically. Useful for non-square matrices or not circular renders. (Can also be width with a rotation.)
Center Smoothing — Blurs the center of the rings to reduce harsh color changes. (Higher = blurrier.)
Idle speed — Minimum speed at any time. Useful to have a not-static effect during music changes or when no movement occurs in the specified frequency range. (Higher = faster.)