要实现在Android上同时使用两个麦克风，可以使用Android的AudioRecord类和AudioTrack类来实现。下面是一个示例代码：

import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaRecorder;

public class DualMicrophone {
    private static final int SAMPLE_RATE = 44100;
    private static final int CHANNEL_CONFIG = AudioFormat.CHANNEL_IN_MONO;
    private static final int AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
    private static final int BUFFER_SIZE = AudioRecord.getMinBufferSize(SAMPLE_RATE, CHANNEL_CONFIG, AUDIO_FORMAT);

    private AudioRecord audioRecord1;
    private AudioRecord audioRecord2;
    private AudioTrack audioTrack;

    public DualMicrophone() {
        audioRecord1 = new AudioRecord(MediaRecorder.AudioSource.MIC, SAMPLE_RATE, CHANNEL_CONFIG, AUDIO_FORMAT, BUFFER_SIZE);
        audioRecord2 = new AudioRecord(MediaRecorder.AudioSource.CAMCORDER, SAMPLE_RATE, CHANNEL_CONFIG, AUDIO_FORMAT, BUFFER_SIZE);

        audioTrack = new AudioTrack(AudioManager.STREAM_VOICE_CALL, SAMPLE_RATE, CHANNEL_CONFIG, AUDIO_FORMAT, BUFFER_SIZE, AudioTrack.MODE_STREAM);
    }

    public void startRecordingAndPlayback() {
        audioRecord1.startRecording();
        audioRecord2.startRecording();
        audioTrack.play();

        byte[] buffer = new byte[BUFFER_SIZE];
        while (true) {
            int bytesRead1 = audioRecord1.read(buffer, 0, BUFFER_SIZE);
            int bytesRead2 = audioRecord2.read(buffer, 0, BUFFER_SIZE);

            audioTrack.write(buffer, 0, bytesRead1);
            audioTrack.write(buffer, 0, bytesRead2);
        }
    }

    public void stopRecordingAndPlayback() {
        audioRecord1.stop();
        audioRecord1.release();

        audioRecord2.stop();
        audioRecord2.release();

        audioTrack.stop();
        audioTrack.release();
    }
}

使用上面的代码，你可以创建一个DualMicrophone对象，并调用startRecordingAndPlayback()方法来开始录制和播放两个麦克风的音频。调用stopRecordingAndPlayback()方法来停止录制和播放。

请注意，上面的代码只是示例，可能还需要进行更多的错误处理和逻辑控制来满足你的实际需求。