Aluminium foil shielding box

In recent 2.4GHz measurement, I suspect the WIFI around here is interfering, to get rid of these annoying WIFI or other 2.4GHz source, a shielding box is made, using aluminium foil, it is found that the top cover need to be in tightly contact with the lower box body, otherwise it's not shielded enough for this bluetooth speaker to shut up. 

Bluetooth speaker as a test sample.

Measuring antenna is insert from the top little hole. Speaker and mobile phone inside.