Spatial Audio on iOS 18 don't work as inteneded

I’m facing a problem while trying to achieve spatial audio effects in my iOS 18 app. I have tried several approaches to get good 3D audio, but the effect never felt good enough or it didn’t work at all.

Also what mostly troubles me is I noticed that AirPods I have doesn’t recognize my app as one having spatial audio (in audio settings it shows "Spatial Audio Not Playing"). So i guess my app doesn't use spatial audio potential.

1. First approach uses AVAudioEnviromentNode with AVAudioEngine. Chaining position of player as well as changing listener’s doesn’t seem to change anything in how audio plays.

Here's simple how i initialize AVAudioEngine

import Foundation
import AVFoundation
 
class AudioManager: ObservableObject {
// important class variables
    var audioEngine: AVAudioEngine!
    var environmentNode: AVAudioEnvironmentNode!
    var playerNode: AVAudioPlayerNode!
    var audioFile: AVAudioFile?
...
   //Sound set up
func setupAudio() {
        do {
            let session = AVAudioSession.sharedInstance()
            try session.setCategory(.playback, mode: .default, options: [])
            try session.setActive(true)
        } catch {
            print("Failed to configure AVAudioSession: \(error.localizedDescription)")
        }
 
        audioEngine = AVAudioEngine()
        environmentNode = AVAudioEnvironmentNode()
        playerNode = AVAudioPlayerNode()
        audioEngine.attach(environmentNode)
        audioEngine.attach(playerNode)
        audioEngine.connect(playerNode, to: environmentNode, format: nil)
        audioEngine.connect(environmentNode, to: audioEngine.mainMixerNode, format: nil)
        environmentNode.listenerPosition = AVAudio3DPoint(x: 0, y: 0, z: 0)
        environmentNode.listenerAngularOrientation = AVAudio3DAngularOrientation(yaw: 0, pitch: 0, roll: 0)
      environmentNode.distanceAttenuationParameters.referenceDistance = 1.0        environmentNode.distanceAttenuationParameters.maximumDistance = 100.0
        environmentNode.distanceAttenuationParameters.rolloffFactor = 2.0
        // example.mp3 is mono sound
        guard let audioURL = Bundle.main.url(forResource: "example", withExtension: "mp3") else {
            print("Audio file not found")
            return
        }
 
        do {
            audioFile = try AVAudioFile(forReading: audioURL)
        } catch {
            print("Failed to load audio file: \(error)")
        }
   }
...
    //Playing sound
    func playSpatialAudio(pan: Float ) {
        guard let audioFile = audioFile else { return }
        //  left side
        playerNode.position = AVAudio3DPoint(x: pan, y: 0, z: 0)
        playerNode.scheduleFile(audioFile, at: nil, completionHandler: nil)
 
        do {
            try audioEngine.start()
            playerNode.play()
        } catch {
            print("Failed to start audio engine: \(error)")
        }
...
}    

1. Second more complex approach using PHASE did better. I’ve made an exemplary app that allows players to move audio player in 3D space. I have added reverb, and sliders changing audio position up to 10 meters each direction from listener but audio seems to only really change left to right (x axis) - again I think it might be trouble with the app not being recognized as spatial.

//Crucial class Variables:
class PHASEAudioController: ObservableObject{
    private var soundSourcePosition: simd_float4x4 = matrix_identity_float4x4
    private var audioAsset: PHASESoundAsset!
    private let phaseEngine: PHASEEngine
    private let params = PHASEMixerParameters()
    private var soundSource: PHASESource
    private var phaseListener:  PHASEListener!
    private var soundEventAsset: PHASESoundEventNodeAsset?
 
// Initialization of PHASE
init{     
 do {
            let session = AVAudioSession.sharedInstance()
            try session.setCategory(.playback, mode: .default, options: [])
 
            try session.setActive(true)
        } catch {
            print("Failed to configure AVAudioSession: \(error.localizedDescription)")
        }
        // Init PHASE Engine
        phaseEngine = PHASEEngine(updateMode: .automatic)
        phaseEngine.defaultReverbPreset = .mediumHall
        phaseEngine.outputSpatializationMode = .automatic //nothing helps        
        // Set listener position to (0,0,0) in World space
        let origin: simd_float4x4 = matrix_identity_float4x4
        phaseListener = PHASEListener(engine: phaseEngine)
        phaseListener.transform = origin
        phaseListener.automaticHeadTrackingFlags = .orientation
        try! self.phaseEngine.rootObject.addChild(self.phaseListener)
        do{
            try self.phaseEngine.start();
        }
        catch {
            print("Could not start PHASE engine")
        }
 
        audioAsset = loadAudioAsset()
        // Create sound Source
        // Sphere
        soundSourcePosition.translate(z:3.0)
        let sphere = MDLMesh.newEllipsoid(withRadii: vector_float3(0.1,0.1,0.1), radialSegments: 14, verticalSegments: 14, geometryType: MDLGeometryType.triangles, inwardNormals: false, hemisphere: false, allocator: nil)
        let shape = PHASEShape(engine: phaseEngine, mesh: sphere)
        soundSource = PHASESource(engine: phaseEngine, shapes: [shape])
        soundSource.transform = soundSourcePosition
        print(soundSourcePosition)
        do {
            try phaseEngine.rootObject.addChild(soundSource)
        }
        catch {
            print ("Failed to add a child object to the scene.")
        }
        let simpleModel = PHASEGeometricSpreadingDistanceModelParameters()
        simpleModel.rolloffFactor = rolloffFactor
        soundPipeline.distanceModelParameters = simpleModel
        
        let samplerNode = PHASESamplerNodeDefinition(
            soundAssetIdentifier: audioAsset.identifier,
            mixerDefinition: soundPipeline,
            identifier: audioAsset.identifier + "_SamplerNode")
        samplerNode.playbackMode = .looping
        do {soundEventAsset = try
            phaseEngine.assetRegistry.registerSoundEventAsset(
            rootNode: samplerNode,
            identifier: audioAsset.identifier + "_SoundEventAsset")
        } catch {
            print("Failed to register a sound event asset.")
            soundEventAsset = nil
        }
}
 
//Playing sound
 func playSound(){
        // Fire new sound event with currently set properties
        guard let soundEventAsset else { return }
        
        params.addSpatialMixerParameters(
            identifier: soundPipeline.identifier,
            source: soundSource,
            listener: phaseListener)
        let soundEvent = try! PHASESoundEvent(engine: phaseEngine,
                                              assetIdentifier: soundEventAsset.identifier,
                                              mixerParameters: params)
        soundEvent.start(completion: nil)
    }
...
}

Also worth mentioning might be that I only own personal team account