How do I connect to a device via bluetooth to play audio?

Question

I have a speaker and I would like to connect to this speaker via bluetooth, to play audio. So far i already managed to turn on bluetooth, as welll as show what devices i am connected too. What i would like to do now is play audio on my speaker, how can i go about doing this? I found some resource online but most of them is to just turn on bluetooth. Any help is grateful thanks in advance.

public class MainActivity extends Activity  {
    Button b1,b2,b3,b4;
    private BluetoothAdapter BA;
    private Set<BluetoothDevice>pairedDevices;
    ListView lv;

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

        b1 = (Button) findViewById(R.id.button);
        b2=(Button)findViewById(R.id.button2);
        b3=(Button)findViewById(R.id.button3);
        b4=(Button)findViewById(R.id.button4);

        BA = BluetoothAdapter.getDefaultAdapter();
        lv = (ListView)findViewById(R.id.listView);
    }

    public void on(View v){
        if (!BA.isEnabled()) {
            Intent turnOn = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(turnOn, 0);
            Toast.makeText(getApplicationContext(), "Turned on",Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(getApplicationContext(), "Already on", Toast.LENGTH_LONG).show();
            //bluetooth is turned on...
        }
    }

    public void off(View v){
        BA.disable();
        Toast.makeText(getApplicationContext(), "Turned off" ,Toast.LENGTH_LONG).show();
    }


    public  void visible(View v){
        Intent getVisible = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
        startActivityForResult(getVisible, 0);
    }


    public void list(View v){
        pairedDevices = BA.getBondedDevices();

        ArrayList list = new ArrayList();

        for(BluetoothDevice bt : pairedDevices) list.add(bt.getName());
        Toast.makeText(getApplicationContext(), "Showing Paired Devices",Toast.LENGTH_SHORT).show();

        final ArrayAdapter adapter = new  ArrayAdapter(this,android.R.layout.simple_list_item_1, list);

        lv.setAdapter(adapter);
    }
}