如何在Android上检测恒定响度的声音的声级

Question

我正在开发一个应用程序，该应用程序应该在某个时刻显示 5 秒时间跨度内用户语音输入的响度。该应用程序用于语音训练，因此用户应该能够始终将声音保持在一定的响度级别。
我使用 MediaRecorder 记录用户的输入，在模拟器上它工作得很好。
但是，当我在外部设备（motorola moto g5s）上运行该应用程序时，该应用程序似乎在 2 秒后将响度下调至非常低的恒定值。

我认为问题可能出在 AudioSource 上，所以我将其从 AudioSource.MIC 切换到 AudioSource.UNPROCESSED 但随后它不允许我在移动设备上录制任何内容（在它正在运行的模拟器上）。

这是由于设备音频硬件中的某些过滤器造成的吗？是否有可能解决这个问题，或者问题可能出在完全不同的地方？

单击按钮时会录制音频：

public void onClick(View view) {

    // when record button is clicked MediaRecorder will record for 5 seconds
    // the time passed recording is shown to the user in the progress bar under the button

    if(view.getId() == R.id.btnRecord){
        System.out.println("\n record was clicked \n");

        // scale volume to range [0:1]
        int max_val = Settings_menu.volumeMax;
        float noiseNow_scaled = (float) Settings_menu.noiseNow/max_val;

        try {
            // recording
            mediaRecorder = new MediaRecorder();
            nativeSampleRate = Integer.parseInt(am.getProperty(AudioManager.PROPERTY_OUTPUT_SAMPLE_RATE));
            System.out.println("\n Native sampling rate: " + nativeSampleRate);
            //nativeSampleBufSize = Integer.parseInt(am.getProperty(AudioManager.PROPERTY_OUTPUT_FRAMES_PER_BUFFER));


            mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
            mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
            path = getRecordingFilePath();
            mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
            mediaRecorder.setAudioSamplingRate(nativeSampleRate);
            mediaRecorder.setOutputFile(getRecordingFilePath());
            mediaRecorder.prepare();
            mediaRecorder.start();

            // play pink noise for masking auditory feedback
            streamID = soundPool.play(pinknoise,noiseNow_scaled , noiseNow_scaled, 0, 0, 1);

        } catch (Exception e){
            e.printStackTrace();

        }

        CountDownTimer timer = new CountDownTimer(5000,LoudnessCalibration.interval) {
            // the maximum loudness of the recording within a LoudnessCalibration.interval ms interval is computed
            // progress bar loads new progress every LoudnessCalibration.interval ms
            // progressbar is filled when 5000 is reached
            @Override
            public void onTick(long l) {
                counter += LoudnessCalibration.interval;
                pb.setProgress(counter);
                amplitudes.add((float) mediaRecorder.getMaxAmplitude());
                length ++;
            }

            // when 5 seconds are over MediaRecorder has to be released & pink noise stops playing
            @Override
            public void onFinish() {
                mediaRecorder.stop();
                mediaRecorder.reset();
                mediaRecorder.release();
                mediaRecorder = null;
                soundPool.stop(streamID);
                pb.setProgress(0);
                counter = 0;
            }
        }.start();

        {...}
}

感谢您对此的任何想法或想法！