Do iOS and/or macOS support Bluetooth LC3? If yes, since what iOS/macOS version? is there any limitation and/or caveat?

I have a voice app that is both playing and recording audio. I have enabled voice processing and am setting AVAudioSession.Category to .playAndRecord and AVAudioSession.Mode to .voiceChat. When the experience first launches, we play a greeting. The first few hundred milliseconds of that greeting are being captured by the inputNode before AEC seems to start working. Is there any way to get AEC working the entire time? For now we've had to disable recording while we're playing audio, but would prefer to both play and record simultaneously. Here's some code snippets: public init(denoiseModelPath: URL? = nil) { noiseReducer = denoiseModelPath.flatMap { NoiseReducer(modelPath: $0) } recorderNode = engine.inputNode speakerNode = engine.outputNode mainMixerNode = engine.mainMixerNode engine.attach(audioPlayer) engine.connect( audioPlayer, to: mainMixerNode, format: nil ) playbackFormat = mainMixerNode.outputFormat(forBus: 0) } public func setupAudioSession() async throws(AudioError) { do { let audioSession = AVAudioSession.sharedInstance() try audioSession.setCategory( .playAndRecord, mode: .voiceChat, policy: .default, options: [ .defaultToSpeaker, .allowBluetoothHFP, ] ) try audioSession.setActive(true) } catch { throw .audioSessionSetupFailed(error) } do { try recorderNode.setVoiceProcessingEnabled(true) try speakerNode.setVoiceProcessingEnabled(true) } catch { throw .enableVoiceProcessingFailed(error) } }

We are working on a voice app that uses ASR/TTS on the backend and run into some difficulties in noisy environments. We have compiled the DeepFilterNet3 library into an XCFramework and are using that on the app, but it's sometimes a bit ambitious with trimming out noise and removes some of the voice. Is there any way to make use of Apple's on-device voice isolation mic mode? I see that we can detect the user's mic mode, but we cannot programmatically set it. While we could prompt the user to enable it manually, this adds a bit of friction to the user experience. Do you have any suggestions for enabling voice isolation, or for performing denoising in general?

Why are none of my posts showing up in the Audio Q&A? There are no errors or any useful messaging... my posts just aren't showing.

My app has a sleep timer (up to 12 hours). Can I drive a Live Activity countdown in the Dynamic Island purely from the foreground/background app process using Activity.update(), without requiring a push notification server? And does Text(timerInterval:) in SwiftUI continue counting down accurately when the app process is suspended by the OS?

Is it appropriate to use the Foundation Models framework on-device to power a natural language sound recommendation feature (e.g. user types 'I can't focus' → model returns a frequency/playlist recommendation from a predefined set)? Or is this use case better served by a custom Core ML model? What's the recommended on-device inference approach in iOS 27 for this type of structured recommendation with a small output space?

With SiriKit deprecated in iOS 27, I'm implementing App Intents from scratch for a frequency/ambient sound app. Should I conform to AudioPlaybackIntent from the Media framework or build a custom AppIntent? Specifically, I need intents for: play a named frequency, start sleep timer with duration, stop playback. Is there a recommended Intent entity type for audio content that isn't music (i.e. not MusicKit-backed)?

We have an VoiP application, our application can be configured to amplify the PCM samples before feeding it to the Player to achieve volume gain at the receiver. In order to support this, We follow as below. If User has configured this Gain Settings within application, Application applies the amplification for the samples to introduce the gain. Application will also set the AVAudioSessionCategory to AVAudioSessionCategoryPlayback Provided the User has chosen the output to Speaker. This settings was working for us but we see there is a difference in behaviour w.r.t Volume Level System Settings between OS 26.3.1 and OS 26.4 When user has chosen earpiece as Output, then we will set the AVAudioSessionCategory to AVAudioSessionCategoryPlayAndRecord. User would have set the volume level to minimum. When user will change the output to Speaker, then we will set the AVAudioSessionCategory to AVAudioSessionCategoryPlayback. The expectation is, the volume level should be of AVAudioSessionCategoryPlayback what was set earlier instead we are seeing the volume level stays as minimum which was set to AVAudioSessionCategoryPlayAndRecord Could you please explain about this inconsistency w.r.t Volume level.

Is there a way to attach a MusicUnderstandingSession to a MusicKit stream or audiofile?

Certain apps (eg. DJay) at least seem to have access to audio data from Apple Music streams, either directly or via an indirect dataset for visualization purposes either generated from audio data on the device or delivered from a remote service. Is there any framework provided by Apple or special agreement with Apple that gives access to Apple Music audio data, or sets of visualization meta data, or the ability to run processing of audio data on device or remotely (either on-demand or via preprocessing)?

Any chance of more modern framework for building AUv3's coming anytime soon?

When the host app of a host/AUv3 extension pair tries to find the audio extension it fails. The system should have scanned the bundle for the extension, but this appears to fail. This basically happens in SimplePlayEngine.initComponent. I've seen this intermittent problem for years. There are many sometimes-effective workarounds that I've gathered and used, but the problem still exists. It is not a problem of validation -- the same AU can validate in some run cycles and then not be found via the host app in others. I've got a Feedback Assistant ticket for the latest iteration of the problem (FB22860885), which has affected beta testers. Usually I only see this when developing with Xcode myself. So even though the testers' app lives in ~/Applications it is still failing for some of them.

This question overlaps with a newer post that contains additional implementation details To avoid splitting discussion, please see: “MusicKit.js / WKWebView: Are audible hitches during seek a known WebKit or Apple Media Stack limitation?” We are building a music practice application that uses MusicKit.js inside a WKWebView on iOS and macOS. Our application requires tight musical looping, where playback repeatedly seeks back to a loop start position while a song is playing. We have observed that: • Seeking to a nearby position within already-buffered audio using HTMLAudioElement.currentTime causes an audible interruption or hitch. • Changing HTMLAudioElement.playbackRate during playback also appears to interrupt playback briefly. • These interruptions make seamless looping difficult to achieve. For comparison, a very similar JavaScript architecture running in a Chromium-based WebView on Android exhibits significantly smoother seek behavior and supports near-seamless looping. Our questions are: Is it expected that changing currentTime or playbackRate on the underlying audio element causes the playback pipeline to be interrupted or rebuilt on Apple platforms? Are there any recommended WebKit, WKWebView, or MusicKit.js techniques that can reduce or eliminate these interruptions when seeking within already-buffered media? Would native MusicKit playback provide lower-latency or more seamless seeking than MusicKit.js, or do both approaches ultimately rely on the same playback pipeline? Our use case is musical practice, where even interruptions of a few tens of milliseconds are noticeable. Any guidance on achieving the smoothest possible loop-seeking behavior on Apple platforms would be greatly appreciated.

Certain apps (eg. DJay) seem to have direct or indirect access to the audio data from Apple Music, either on the device or remotely preprocessed. Is that feature available for other third party apps? Am I correct in my understanding that the new framework MusicUnderstanding (which looks quite interesting, judging from the docs so far) is not in any way usable for streams or local files from Apple Music / MusicKit since it relies entirely on AVReadOnlyAudioPCMBuffer? Is there eg. a way to get the same kind of music understanding data (or some other meta data suitable for real time visualization) provided directly form Apple Music without going via a readable audio buffer?

What's the best way of dealing with presentation mode (when the phone screen is captured by Google Meet or any other presenter software) when AudioSession is activated with .playAndRecord mode? The goal is to share the audio output between the phone and Google Meet so participants can hear it as well, while also enabling a microphone for future interactions within the app, for, let's say, voice chat.

Up to iOS 18 there were many voices available on device by default including "Nicky" that I use in my app. Somewhere around iOS 18.6 or 26.0 these voices were removed and no longer included in the OS by default. This broke my app that counted on the Nicky voice being available. My only workaround is to direct my users to download the voice again by going to Accessibility > VoiceOver > Speech > Voices and downloading "Nicky". I cannot simply switch to using Samantha (the only voice that is still available by default) because I have heavily customized how IPA pronunciations are tweaked to make Nicky speak Old English correctly. I tried briefly with Samantha but the results were not as good. I have 2 questions: Is there any way for me to include the "Nicky" voice in my app or for me to trigger the download from the app so I don't have to show an error and direct users through the settings app to get the voice? Are there any new features with AI voices in iOS 27 that I can use with IPA pronunciations to get them to speak possibly better than the Nicky voice?

I need to apply headphone-specific scenario only when headphones are the sole active playback device in my iOS audio app. Problem that there is no absolute way to definitively understand that headphones are the sole active playback device AVAudioSession.currentRoute.outputs portTypes don't guarantee headphones: let session = AVAudioSession.sharedInstance() let outputs = session.currentRoute.outputs let headphonesOnly = outputs.count == 1 && (outputs.first?.portType == .headphones || outputs.first?.portType == .bluetoothA2DP || outputs.first?.portType == .bluetoothHFP || outputs.first?.portType == .bluetoothLE) The issue in code above that listed bluetooth profiles (A2DP, HFP, LE) can be used by any audio device, not only headphones Is there any public API on iOS that can: Distinguish Bluetooth headphones vs Bluetooth speakers when both use A2DP/LE? Expose the user’s “Device Type” classification (headphones / speaker / car stereo, etc.) that is shown in Settings → Bluetooth → Device Type? Provide a more reliable way to know “this route is definitely headphones” for A2DP devices, beyond portType and portName string heuristics?

Description: I have identified a specific issue when recording acoustic guitar and other instruments on the iPhone 17 Pro Max using native applications (Voice Memos, Camera). The recordings contain an unnatural metallic resonance (ringing artifacts) that should not be present. Testing and Methodology: Hardware Verification: Initially, I suspected a hardware defect in the audio chip or microphone. However, extensive testing with third-party software suggests this is likely a software-level issue. AudioShare Test: I conducted a test using the AudioShare app in "Measurement Mode" (which bypasses standard iOS system-wide audio processing). In this mode, the audio remains perfectly clean, and the metallic ringing disappears entirely. Conclusion: The issue is rooted in the DSP (Digital Signal Processing) algorithms that iOS applies for noise suppression or voice enhancement. These algorithms appear to misinterpret the high-frequency overtones of acoustic instruments as background noise and attempt to "filter" them, resulting in audible digital artifacts. Comparison Results: This issue has not been observed on devices from other brands or on older iPhone models (preliminary tests suggest older versions handle this better). Notably, the problem persists even in GarageBand, as the app still utilizes certain system-level processing layers. Proposed Solution: I suggest adding a "Raw Audio" or "Instrument Mode" toggle within the Microphone/Audio settings for native apps. This mode should disable aggressive DSP processing, similar to how the AVAudioSession.Mode.measurement works in specialized apps. Attachments: I am attaching 4 archives, including a final "Measurement Mode" folder with comparative samples (Measurement Mode vs. Standard Mode). The artifacts are most prominent when monitored through headphones.

I have an AUv3 plug-in that works on both iOS and macOS. Some users have complained that after they create a track in Logic Pro (on either iPad or Mac version) and insert my plug-in as an instrument, the track always shows "Untitled" instead of the name of the active preset. Even if the user changes the factory preset, it still says "Untitled". I started debugging my AUv3 API usage for presets, specifically currentPreset and factoryPresets and tried pretty much everything with no success. For example, I tried overriding and not overriding currentPreset, and I tried issuing KVO for currentPreset. But Logic Pro still shows "Untitled" in all cases. In the following screenshot, I'm selecting a factory preset using Logic's interface. Here we see the factory preset is selected and diplayed using the UI of my plug-in, but Logic's interface is still showing Untitled. I noticed AUv2 plug-ins don't seem to suffer from this issue. For example, FabFilter Pro-Q 3 doesn't expose its factory parameters, but I can create a custom preset inside it or load a factory preset and Logic's interface will display the name of the plug-in. I'm assuming the v2 API kAudioUnitProperty_PresentPreset doesn't suffer fron this issue? Here's Logic Pro showing Pro-Q 3's custom preset name I created using the plug-in interface. Is there a solution to this? Or is this a bug? And then whose bug is it Logic's or Core Audio?

A recent WWDC session "Learn about Apple Immersive Video technologies" showed a Apple Spatial Audio Format Panner plugin for Pro Tools. The presenter stated that it's available on a per-user license. Where can users access this?