text: Q:
  
  How to duplicate one stereo channel to the other stereo channel using AudioKit
  
  I am using a Focusrite Scarlett 2i2 into a Mac. The signal into the Scarlett is a guitar.
  With code along these lines I can get audio into the, app, but it is only the stereo left channel.
  mic = AKMicrophone()
  device = AKDevice(name:"Scarlett 2i4 USB", deviceID:56);
  
  mic.setDevice(device)
  
  let booster = AKBooster(mic, gain: 1.0)
  
  AudioKit.output = booster
  
  AudioKit.start()
  
  mic.start()
  
  Is there a simple way to combine left and right channels from a mic input into a single mono signal (or left and right with the same signal)?
  I tried a variation on this answer about flipping left and right channels: AudioKit - Stereo channel flipping from input to output?
  But that didn't work. FWIW, it also didn't work for purely flipping the channels (AKPanner seems to be able to pan something from the center to hard left, but not from hard left to center or right.) 
  Two other things that might be related:
  
  It seems that AKStereoInput is not available for the Mac platform. Is that correct?
  What exactly is "deviceID"? I seem to be able to change that and get the same result.
  
  Thank you.
  
  A:
  
  Yes, there is something called AKStereoFieldLimiter that does just that:
  https://audiokit.io/docs/Classes/AKStereoFieldLimiter.html
  
  