I need to get the microphone output in a certain format that isn't equal to the hw format. To do this, I'm creating a AVAudioMixerNode which will have that format as it's output. However, I never receive any buffers when installing the tap on the mixer node. I thought the inputNode would flow upstream? Am I doing something wrong? Note that I'm not using AudioUnits or AudioQueues because I need to do some frequency filtering on the actual audio stream and thought this was the easiest way to do it.Here's the code:mixerNode = [[AVAudioMixerNode alloc]init]; //Attach node [theEngine attachNode:mixerNode]; //Then connect inputNode (mic) to mixer node [theEngine connect:theEngine.inputNode to:mixerNode format:[theEngine.inputNode outputFormatForBus:0]]; [theEngine startAndReturnError:&theError]; //Now set up the real audio format i want AudioStreamBasicDescription audioFormat; audioFormat.mSampleRate = 8000; audioFormat.mChannelsPerFrame = numberOfChannels; audioFormat.mFormatID = kAudioFormatLinearPCM; audioFormat.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger; audioFormat.mBitsPerChannel = 16; audioFormat.mBytesPerPacket = audioFormat.mBytesPerFrame = (audioFormat.mBitsPerChannel / 8) * audioFormat.mChannelsPerFrame; audioFormat.mFramesPerPacket = 1; //Now install the tap on the mixer so we get the correct format [mixerNode installTapOnBus:0 bufferSize:4096 format:[[AVAudioFormat alloc]initWithStreamDescription:&audioFormat] block:^(AVAudioPCMBuffer * _Nonnull buffer, AVAudioTime * _Nonnull when) { NSLog(@"got buff"); }];