Hi there, I didn't use ShazamKit, just audio & mixer nodes but I got the same crash required condition is false: IsFormatSampleRateAndChannelCountValid(format) I follow your article https://developer.apple.com/documentation/shazamkit/matching-audio-using-the-built-in-microphone but still didn't work. The problem is that issue only reported on crashlytics from my user and I can't reproduce on my device. Fatal Exception: com.apple.coreaudio.avfaudio 0 CoreFoundation 0x2d5fc __exceptionPreprocess 1 libobjc.A.dylib 0x31244 objc_exception_throw 2 CoreFoundation 0x17a6e0 -[NSException initWithCoder:] 3 AVFAudio 0x634d8 AUGraphNodeBaseV3::CreateRecordingTap(unsigned long, unsigned int, AVAudioFormat*, void (AVAudioPCMBuffer*, AVAudioTime*) block_pointer) 4 AVFAudio 0x112624 AVAudioEngineImpl::InstallTapOnNode(AVAudioNode*, unsigned long, unsigned int, AVAudioFormat*, void (AVAudioPCMBuffer*, AVAudioTime*) block_pointer) 5 AVFAudio 0xe7fa0 -[AVAudioNode installTapOnBus:bufferSize:format:block:] 6 Runner 0x1b2f8 closure #1 in SpeechController.initializeAudioInputEngine() + 1269 (SpeechController.swift:1269) 7 Runner 0x11c28 partial apply for thunk for @callee_guaranteed () -> () + 573 (AssetController.swift:573) 8 Runner 0x15160 thunk for @escaping @callee_guaranteed () -> () (<compiler-generated>) 9 libdispatch.dylib 0x3fa8 _dispatch_client_callout 10 libdispatch.dylib 0x137fc _dispatch_lane_barrier_sync_invoke_and_complete 11 Runner 0x1aec8 SpeechController.initializeAudioInputEngine() + 1235 (SpeechController.swift:1235) 12 Runner 0x1f750 SpeechController.applicationWillEnterForeground() + 1923 (SpeechController.swift:1923) 13 Runner 0x13e6c AppDelegate.applicationWillEnterForeground(_:) + 133 (AppDelegate.swift:133) 14 Runner 0x13ee0 @objc AppDelegate.applicationWillEnterForeground(_:) (<compiler-generated>) 15 UIKitCore 0x3f24d0 -[UIApplication _sendWillEnterForegroundCallbacks] 16 UIKitCore 0x3eeb84 __101-[_UISceneLifecycleMultiplexer _evalTransitionToSettings:fromSettings:forceExit:withTransitionStore:]_block_invoke_2 17 UIKitCore 0x24f5e4 _UIScenePerformActionsWithLifecycleActionMask 18 UIKitCore 0x3ef00c __101-[_UISceneLifecycleMultiplexer _evalTransitionToSettings:fromSettings:forceExit:withTransitionStore:]_block_invoke 19 UIKitCore 0x3eed1c -[_UISceneLifecycleMultiplexer _performBlock:withApplicationOfDeactivationReasons:fromReasons:] 20 UIKitCore 0x1b5834 -[_UISceneLifecycleMultiplexer _evalTransitionToSettings:fromSettings:forceExit:withTransitionStore:] 21 UIKitCore 0x1b5554 -[_UISceneLifecycleMultiplexer uiScene:transitionedFromState:withTransitionContext:] 22 UIKitCore 0x1b500c __186-[_UIWindowSceneFBSSceneTransitionContextDrivenLifecycleSettingsDiffAction _performActionsForUIScene:withUpdatedFBSScene:settingsDiff:fromSettings:transitionContext:lifecycleActionType:]_block_invoke 23 UIKitCore 0x1b41b4 +[BSAnimationSettings(UIKit) tryAnimatingWithSettings:fromCurrentState:actions:completion:] 24 UIKitCore 0x1b37ec _UISceneSettingsDiffActionPerformChangesWithTransitionContextAndCompletion 25 UIKitCore 0x1b349c -[_UIWindowSceneFBSSceneTransitionContextDrivenLifecycleSettingsDiffAction _performActionsForUIScene:withUpdatedFBSScene:settingsDiff:fromSettings:transitionContext:lifecycleActionType:] 26 UIKitCore 0x24f394 __64-[UIScene scene:didUpdateWithDiff:transitionContext:completion:]_block_invoke.229 27 UIKitCore 0x24ece4 -[UIScene _emitSceneSettingsUpdateResponseForCompletion:afterSceneUpdateWork:] 28 UIKitCore 0x246708 -[UIScene scene:didUpdateWithDiff:transitionContext:completion:] 29 UIKitCore 0x245ee8 -[UIApplicationSceneClientAgent scene:handleEvent:withCompletion:] 30 FrontBoardServices 0xc290 __76-[FBSScene updater:didUpdateSettings:withDiff:transitionContext:completion:]_block_invoke.146 31 FrontBoardServices 0x9834 -[FBSScene _callOutQueue_coalesceClientSettingsUpdates:] 32 FrontBoardServices 0x7090 -[FBSScene updater:didUpdateSettings:withDiff:transitionContext:completion:] 33 FrontBoardServices 0x1f868 __94-[FBSWorkspaceScenesClient _queue_updateScene:withSettings:diff:transitionContext:completion:]_block_invoke_2 34 FrontBoardServices 0x1f4c8 -[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:] 35 FrontBoardServices 0xa510 __94-[FBSWorkspaceScenesClient _queue_updateScene:withSettings:diff:transitionContext:completion:]_block_invoke 36 libdispatch.dylib 0x3fa8 _dispatch_client_callout 37 libdispatch.dylib 0x79f0 _dispatch_block_invoke_direct Here is my code: var engine = AVAudioEngine() let mixer = AVAudioMixerNode() let soundNode = AVAudioPlayerNode() let speechNode = AVAudioPlayerNode() engine.attach(mixer) engine.connect(mixer, to: engine.outputNode, format: nil) // Add the sound effects and looping node players engine.attach(soundNode) engine.connect(soundNode, to: mixer, format: nil) let speechFormat = AVAudioFormat.init( standardFormatWithSampleRate: 32000, channels: 1) engine.attach(speechNode) engine.connect(speechNode, to: mixer, format: speechFormat) let audioSession = AVAudioSession.sharedInstance() try audioSession.setCategory( AVAudioSession.Category.playAndRecord, mode: mode, options: [.defaultToSpeaker, .allowBluetooth]) try audioSession.setPreferredSampleRate(micSampleRate) try audioSession.setActive(true) try engine.inputNode.setVoiceProcessingEnabled(true) try engine.outputNode.setVoiceProcessingEnabled(true) engine.inputNode.removeTap(onBus: kBus) // buffer needs to be 100ms for good latency engine.inputNode.installTap( onBus: kBus, bufferSize: UInt32(inputFormat!.sampleRate * kBufferDuration), format: inputFormat! ) { buffer, _ in guard self.microphoneEnabled, !self.appInBackground else { self.recognize(buffer: buffer) } Can you look at is there anything wrong with my code? Thank you!