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CHORUS Fred Anton Corvest

This may be the chorus you've been looking for the whole time!

Download on the App Store
  • Engineered to mimic the behaviour of some famous classic chorus modules
  • Provides some unique features such as the chorus type
  • Feedback control, gives metal characteristics to the sound or makes it fuller
  • Suitable for any situation, going from subtle to drastic changes
  • Super clean and smooth UI, very responsive knobs
  • Supports most of your iPhone/iPad input devices (mic and USB devices)
  • Audio Unit V3 (Host provided, supported in GarageBand, AudioBus3, AUM...)

Main features

The interface has a unique sober look and provides a great user experience. For example the value of each knob can be monitored at any time and a led provides a visual monitoring of the signal level. The knobs are very responsive and natural and follow a specific curve according to the parameters type.

The effect is built upon two individual delay line paths controlled by common parameters. The behaviour of each delay signal path is defined by the chorus type parameter. Thick type means warm characters and emulates the behaviour of the BBD. Clean type, as the name says, provides a cleaner sound with a larger modulation.

Following the diagram below, the sound flows from the left to right or from the input to the output.

  • Gain (up to 15db) Use it carefully
  • Stereo signal to mono
  • Bass boost
  • Input devices*: mic, usb devices...
  • Delay duration
  • Amount of feedback
  • Modulation rate
  • Modulation depth
  • Chorus mode - Thick or Clean
  • Modulation waveform - Sin or Tri
  • Dry/Wet mix signal control
  • Gain (up to 15db) Use it carefully
  • Stereo image width control:
    from mono to wide
  • Signal level monitoring
  • Bypass*

*Available in the provided host app only

A set of factory presets also provides an overview of the sonic panel you can obtain.

Warning about the "Larsen effect".In the input section, it's possible to choose a mic as input. This may cause audio feedback, check your levels to avoid any damage to your system. Furthermore, use the gain and feedback in parsimony, to avoid any excessive levels that may damage your ears or your system. FAC Chorus shall not be liable for any loss or damage of whatever nature (direct, indirect, consequential, or other) to your material (software, hardware, or other).


FAC Chorus - AUM

I'm trying it out right now and I'm already in love with it! Great warm sound, very nice on vocals, bass and guitar. Up to crazy sounds that still sound warm and analogue

Thomas Büchel

I've looked for a Roland Juno-esqe chorus for a long while, and was ecstatic to find this


I really like it. Nice subtle capabilities and deep, rich and lush strengths

Smite Matter

Thanks for your great effort to make an outstanding FX plugin! Love it truly!


This is just spectacularly good, It just lifts the instrument with richness and warmth...lovely


This app is like hot chocolate with whipped cream...Makes it so warm and yummy


Download on the App Store

FAC Chorus is the result of the labor of one passionate software engineer, Fred Anton Corvest alias FAC

Why FAC Chorus isn't for free?

At the begining of the project I wanted to release the app for free, but after discussion with many people I've decided to go for a paid version. After all, work deserves to be rewarded!

Be greatful, understand that releasing a product takes time and a lot of energy, there are a lot of aspects beyond the technical ones. You have to endorse all the roles involved in a project, so a lot of people.

I have ideas and I plan some interesting releases, so be patient. You know now, behind any feature there is a lot of work.

Do not ask for Windows and Android support because it’s not planned to put any effort on it.

Focus is AUV3, with full support of iOS, and soon OSX.

A bit of history

The development of the effect itself has begun in the begining of 2017. The sdk engine, or the classes involved in the data signal processing have been developed since a couple of years now, no plan to switch to anything else. A special UI framework has also been developed since early 2016. All the development has been performed during free time (evenings, nights, week-ends and vacations).

As a small contribution to the DSP community, any development or technical recommendation helpfull to other developers are provided to Git Hub.

FAC Chorus has passed a beta period of roughly two months, the app has been tested intensively by a beta tester team of 10 persons. They have done a great job!