Acoustic metamaterials have shown great potential for a number of acoustic applications due to their extraordinary, tunable acoustic properties such as deep sub-wavelength sound absorption, bandgaps, and focusing to name a few. Likewise, multiscale sorptive porous media have been shown to exhibit remarkable acoustic properties, including unusually high low frequency sound absorption and enabling the enhancement of the compliance of resonator's cavities or loudspeaker's boxes. This work applies labyrinthine metamaterials and multiscale sorptive porous materials to the design of vented-box loudspeakers. An electro-mechano-acoustical model of a vented-box loudspeaker is introduced. This model takes into account the effects of the said meta- and porous material on the vented-box loudspeaker's sensitivity and electrical impedance. It is shown that by combining both types of materials, the form factor of vented-box loudspeakers can be significantly reduced, without compromising their low frequency performance. Thus, this work contributes towards the sought-after'holy grail' of loudspeaker's design; that is to achieve'big bass from small boxes'.