mAudioRecorder = AudioRecorder.getInstance();
mAudioFile = new File(
        Environment.getExternalStorageDirectory().getAbsolutePath() +
                File.separator + System.nanoTime() + ".file.m4a");
mAudioRecorder.prepareRecord(MediaRecorder.AudioSource.MIC,
        MediaRecorder.OutputFormat.MPEG_4, MediaRecorder.AudioEncoder.AAC,
        mAudioFile);
mAudioRecorder.startRecord();
// ...
mAudioRecorder.stopRecord();

mRxAudioPlayer.play(PlayConfig.file(audioFile).looping(true).build())
        .subscribeOn(Schedulers.io())
        .subscribe(new Action1<Boolean>() {
            @Override
            public void call(Boolean aBoolean) {
                // play finished
                // NOTE: if looping, the Single will never finish, you need stop playing
                // onDestroy, otherwise, memory leak will happen!
            }
        });

PlayConfig.file(audioFile) // play a local file
    //.res(getApplicationContext(), R.raw.audio_record_end) // or play a raw resource
    .looping(true) // loop or not
    .leftVolume(1.0F) // left volume
    .rightVolume(1.0F) // right volume
    .build(); // build this config and play!

mOutputFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath() +
        File.separator + System.nanoTime() + ".stream.m4a");
mOutputFile.createNewFile();
mFileOutputStream = new FileOutputStream(mOutputFile);
mStreamAudioRecorder.start(new StreamAudioRecorder.AudioDataCallback() {
    @Override
    public void onAudioData(byte[] data, int size) {
        if (mFileOutputStream != null) {
            try {
                mFileOutputStream.write(data, 0, size);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void onError() {
        mBtnStart.post(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(getApplicationContext(), "Record fail",
                        Toast.LENGTH_SHORT).show();
                mBtnStart.setText("Start");
                mIsRecording = false;
            }
        });
    }
});

Observable.just(mOutputFile).subscribeOn(Schedulers.io()).subscribe(new Action1<File>() {
    @Override
    public void call(File file) {
        try {
            mStreamAudioPlayer.init();
            FileInputStream inputStream = new FileInputStream(file);
            int read;
            while ((read = inputStream.read(mBuffer)) > 0) {
                mStreamAudioPlayer.play(mBuffer, read);
            }
            inputStream.close();
            mStreamAudioPlayer.release();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
});