Doubler.

Doubler thickens and widens a source using four independent voices, each combining delay with pitch modulation. Every voice carries the same set of controls, its own modulation depth and rate, and detuning up to 100 cents with an octave-down switch. Output filtering with high and low shelves shapes how the copies sit against the original. It suits lead and backing vocals, spreads mono instruments, and pushes far enough into modulation to work as a sound design tool.