How can I improve audio quality with natcorder?

public void StartRecording()
{
StartRec();

            // Create a recording configuration
            const float DownscaleFactor = 2f / 3;
            var configuration = new Configuration((int)(Screen.width * DownscaleFactor), (int)(Screen.height * DownscaleFactor));

            // Start recording with microphone audio
            if (recordMicrophoneAudio)
            {
                // Start the microphone
                audioSource.clip = Extensions.Microphone.StartRecording();
                audioSource.loop = true;
                audioSource.Play();
                // Start recording with microphone audio
                Replay.StartRecording(Camera.main, configuration, OnReplay, audioSource, true);
                Debug.Log("microphone function");
            }

            // Start recording without microphone audio
            else
            {
                Replay.StartRecording(Camera.main, configuration, OnReplay, audioSource, false);
                Debug.Log("else function");
            }

                
        }

This is my C# sources.

There is no problem with the quality of the recorded video, but the quality of the audio is very bad. Do you know how to adjust the sound quality?

Please help me…

what exactly problem ?
and do you have solution?