title: Enhancing voice recording with AVAudioEngine like in Voice Memos
body: <p>I'm trying to implement a similar functionality like was added to Voice Memos in iOS 14. As far as I know it reduces background noise and removes echo.</p>
  <p>The overall goal is to make voice recording sound better by presumably cutting noise, removing echo, slightly increasing bass and normalizing the result.</p>
  <p>I've tried using 2 EQs: ~80Hz high-pass and ~1050Hz low-pass (assuming those are the ~ranges for human voice), but it does virtually nothing. I'm very new to audio processing, so I have nearly no idea what am I doing wrong.</p>
  <pre><code>eq.bypass = false
  
  let cutLower = eq.bands[0]
  cutLower.filterType = .highPass
  cutLower.frequency = 82
  cutLower.bypass = false
  cutLower.gain = 3
  cutLower.bandwidth = 1
      
  let cutHigher = eq.bands[1]
  cutHigher.bypass = false
  cutHigher.filterType = .lowPass
  cutHigher.frequency = 1047
  cutHigher.gain = 3
  cutHigher.bandwidth = 1
  </code></pre>
  <p>Checked all the filters/effects available in the engine, but couldn't find anything remotely appropriate.</p>
  <p>I also looked into AudioKit, but since I need to do manual rendering (apply effects without playing the recording) and all the docs on the topic seem outdated, I went with plain AVAudioEngine.</p>