Limiter - Audio Processor
"A brickwall peak limiting app, for the complete control of your audio volume.
It has a wide range of dynamic processing: from very gentle volume attenuation to heavy distortion" from the App Store description.
App type: Audiobus and IAA
App store link: 
Limiter - Audio Processor
Developer: Amazing Noises
Developer AB Forum Handle: @mauriziogiri
Additional Info
The app has normalizer and saturation options too.
Tips and Tricks
Videos
Limiter by Amazing Noises new version for iPad iPhone
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