title: AudioKit AKSampler makes strange feedback noise
body: <p>I'm using AudioKit AKSampler in my app to play piano sound, and it's working fine on my phone(iPhone 5), but when I checked on other phones(iPhone8, iPhone6) the sampler makes a strange feedback sound and a strange noise in the background.</p>
  
  <p>Is this something you are familiar with? Is it the OS version number, or the device?
  Any help?</p>