The Double Infrahorn is a waveguide which can be used in conjunction with a pair of Infrabass 218s for applications with extreme low-frequency bass requirements. When bolted directly to the front of two Infrabass, the waveguide increases the output of the pair by up to 10dB at 33Hz. The additional loading provided by the Infrahorn significantly enhances both the efficiency and directivity of the Infrabass. Double Infrahorns can be used singly or stacked above each other in multiples to produce unprecedented low-bass performance. Where space permits, the Double Infrahorn represents a cost effective way of maximising Infrabass output, whether it be for use within the club environment or for outdoor arenas.