手机麦克风声音现场录音和手机扬声器播放效果不佳

Question

我尝试开发扬声器应用程序。音频输入内置于手机麦克风中。音频输出内置于手机扬声器。我开发了那个应用程序，但效果不佳。我说＆＃34;你好＆＃34;电话麦克风没有回应。我下次尝试吹空气给手机麦克风。响应声音有很多回声和空气噪音。如何解决这个问题。

更新
一些设备响应声音是不同的。我不知道这取决于设备规格。

参考：
Android AudioRecord class - process live mic audio quickly, set up callback function
Live Audio Recording and Playing in Android and Thread & callback handling

我的代码：MainActivity.java

package bm.app.loudspeaker;

import android.app.Activity;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ToggleButton;

public class MainActivity extends Activity {

    Thread m_thread; 

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        m_thread = new Thread(new Runnable() {

            @Override
            public void run() {

                loopBack();
            }
        });



        final ToggleButton butSwitch = (ToggleButton)findViewById(R.id.butSwitch);

        butSwitch.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (butSwitch.isChecked()) {

                    m_thread.start();
                }
                else{

                }

            }
        });
    }



    boolean m_isRun = true;
    int bufferSize = 0;
    int SAMPLE_RATE = 8000;
    AudioRecord m_record;
    AudioTrack m_track;
    byte[] buffer;
    int         ix       = 0;

    public void loopBack(){
        try {
            bufferSize = AudioRecord.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_CONFIGURATION_MONO, 
                    AudioFormat.ENCODING_PCM_16BIT);

//          if (bufferSize <= BUF_SIZE) {
//              bufferSize = BUF_SIZE;
//          }

            Log.i("LOG","Initializing Audio Record and Audio Playing objects");

            m_record = new AudioRecord(MediaRecorder.AudioSource.MIC, SAMPLE_RATE, AudioFormat.CHANNEL_CONFIGURATION_MONO
                    , AudioFormat.ENCODING_PCM_16BIT, bufferSize * 1);

            m_track = new AudioTrack(AudioManager.STREAM_MUSIC, SAMPLE_RATE, AudioFormat.CHANNEL_CONFIGURATION_MONO
                    , AudioFormat.ENCODING_PCM_16BIT, bufferSize * 1
                    , AudioTrack.MODE_STREAM);

            m_track.setPlaybackRate(SAMPLE_RATE);

            m_record.startRecording();
            Log.i("LOG","Audio Recording started");

            m_track.play();
            Log.i("LOG","Audio Playing started");

            buffer = new byte[bufferSize];

            while (m_isRun) {

                m_record.read(buffer, 0, bufferSize);
                m_track.write(buffer, 0, buffer.length);


            }

            Log.i("LOG", "loopback exit");

        } catch (Exception e) {
            // TODO: handle exception
        }

    }
}