Bass Trap - A low frequency absorber. Low frequencies are particularly difficult to absorb due to their long wavelengths. Bass traps are designed and constructed to absorb these longer Wavesand control unwanted room resonances. Broadband absorbers extending to lower frequencies are often called Bass Traps, imprecisely. The term “bass trap” is counterintuitive since these devices eliminate low frequency room cancellations, allowing bass to be heard.