Azure kinect dk beamforming angle how to detect?

I have microsoft azure kinect dk device. This device have 7 microphones array.

I using azure SpeechRecognizer and get audio from specific angle. But all angle will recognize.

Start angle 70, End angle 110.

        static void Main(string[] args)
        { 
            SpeechConfig speechConfig;
            AudioProcessingOptions audioProcessingOptions;
            AudioConfig audioInput;
            SpeechRecognizer recognizer = null;

            bool initial = false;
            // https://video2.skills-academy.com/zh-cn/azure/ai-services/speech-service/how-to-select-audio-input-devices
            var enumerator = new MMDeviceEnumerator();
            
            foreach (var endpoint in
                     enumerator.EnumerateAudioEndPoints(DataFlow.Capture, DeviceState.Active))
            {
                Console.WriteLine("{0} ({1})", endpoint.FriendlyName, endpoint.ID);

                if (endpoint.FriendlyName.Contains("Azure Kinect Microphone Array"))
                {
                    speechConfig = SpeechConfig.FromSubscription("xxx", "xxx");
                    speechConfig.SpeechRecognitionLanguage = "zh-CN";

                    MicrophoneCoordinates[] microphoneCoordinates = new MicrophoneCoordinates[7]
                    {
                        new MicrophoneCoordinates(0, 0, 0),
                        new MicrophoneCoordinates(40, 0, 0),
                        new MicrophoneCoordinates(20, -35, 0),
                        new MicrophoneCoordinates(-20, -35, 0),
                        new MicrophoneCoordinates(-40, 0, 0),
                        new MicrophoneCoordinates(-20, 35, 0),
                        new MicrophoneCoordinates(20, 35, 0)
                    };
                    var microphoneArrayGeometry = new MicrophoneArrayGeometry(MicrophoneArrayType.Planar, 70, 110, microphoneCoordinates);

                    audioProcessingOptions = AudioProcessingOptions.Create(AudioProcessingConstants.AUDIO_INPUT_PROCESSING_ENABLE_DEFAULT, microphoneArrayGeometry, SpeakerReferenceChannel.LastChannel);
                    audioInput = AudioConfig.FromMicrophoneInput(endpoint.ID, audioProcessingOptions);

                     recognizer = new SpeechRecognizer(speechConfig, audioInput);
                    initial = true;
                    break;
                }
            }
            if (!initial)
            {
                Console.WriteLine("initial error no device");
                return;
            }


            // Subscribes to events.
            recognizer.Recognizing += (s, e) =>
            {
                Console.WriteLine($"RECOGNIZING: Text={e.Result.Text}");
            };

            recognizer.Recognized += (s, e) =>
            {
                if (e.Result.Reason == ResultReason.RecognizedSpeech)
                {
                    Console.WriteLine($"RECOGNIZED: Text={e.Result.Text}");
                }
                else if (e.Result.Reason == ResultReason.NoMatch)
                {
                    Console.WriteLine($"NOMATCH: Speech could not be recognized.");
                }
            };

            recognizer.Canceled += (s, e) =>
            {
                Console.WriteLine($"CANCELED: Reason={e.Reason}");

                if (e.Reason == CancellationReason.Error)
                {
                    Console.WriteLine($"CANCELED: ErrorCode={e.ErrorCode}");
                    Console.WriteLine($"CANCELED: ErrorDetails={e.ErrorDetails}");
                    Console.WriteLine($"CANCELED: Did you update the subscription info?");
                }
                 
            };

            recognizer.SessionStarted += (s, e) =>
            {
                Console.WriteLine("\nSession started event.");
            };

            recognizer.SessionStopped += (s, e) =>
            {
                Console.WriteLine("\nSession stopped event.");
                Console.WriteLine("\nStop recognition."); 
            };

            Task task = recognizer.StartContinuousRecognitionAsync();
            Task.WhenAll(task).Wait(); 


            Thread.Sleep(200000); 
        }

Where is Start angle 70, End angle 110?