RP-1 Delay is a versatile dual digital delay FX program for iPhone. It features two separate stereo delay lines that offer a spectrum of effects, from traditional slapback echoes to intricate modulations and ambient soundscapes. The software includes digital stereo delay with high- and low-pass filters, stereo spread, and looping capabilities. Additionally, users can access a separate modulation delay for chorus, vibrato, flanger, panning, phaser, and tremolo effects, with the option to bypass each section individually.

With delay times ranging from 10ms to 2000ms (or 1/32 to 2 bars), RP-1 Delay provides tempo sync via AudioUnit Host or Ableton Link, tap tempo, manual tempo adjustments, and different rhythmic subdivisions like normal, dotted, and triplet. The program also offers stereo spread control and straightforward one-button looping, making it a comprehensive tool for creating unique audio effects.