RP-1 for iOS gives you dual delay lines and complete connectivity

Lines of duty: RP-1 gives you dual delays.
Lines of duty: RP-1 gives you dual delays.

With a variety of connectivity standards now well established, developers are starting to take iOS effect processing apps seriously. RP-1 is the latest one to roll out of the garage, offering dual digital delay lines for iPad and iPhone.

Delay I is said to be 'Long' and suitable for creating trailing echoes, simple splash backs or precise rhythmic effects. The 'Short' Delay II meanwhile, is designed to create modulation effects such as chorus, vibrato and flanging.

The delay lines can be combined as you wish or used independently, while true stereo processing is applied throughout the signal chain.

RP-1 can run standalone or as an Audio Unit Extension in a compatible host, and it also supports Inter-App Audio, AudioBus and Ableton Link. You can buy it now from the Apple App Store for £4.49/$5.99 or find out more on the Numerical Audio website.

Numerical Audio RP-1 specs

Delay Section

  • Delay times from 10ms to 2000ms or 1/32th to 4bars
  • Lowpass and Highpass filters (Pre Delay)
  • Stereo Spread
  • Tempo Sync via AU Host or Ableton Link
  • Tap Tempo and Manual Tempo
  • Normal, Dotted and Triplet mode
  • One Button Looping
  • Effect Bypass

Mod Section

  • Chorus, Vibrato, Flanger and Panning mode
  • Modulation Amount
  • Modulation Frequency from 0.1hz to 10hz
  • Routing Pre/Post Delay
  • Mod Bypass
Ben Rogerson

I’m the Deputy Editor of MusicRadar, having worked on the site since its launch in 2007. I previously spent eight years working on our sister magazine, Computer Music. I’ve been playing the piano, gigging in bands and failing to finish tracks at home for more than 30 years, 24 of which I’ve also spent writing about music and the ever-changing technology used to make it.