Various methods and apparatus for processing audio signals are disclosed herein. The assembly may be attached, adhered, or otherwise embedded into or upon a removable oral appliance to form a hearing aid assembly. Such an oral appliance may be a custom-made device which can enhance and/or optimize received audio signals for vibrational conduction to the user. Received audio signals may be processed to cancel acoustic echo such that undesired sounds received by one or more intra-buccal and/or extra-buccal microphones are eliminated or mitigated. Additionally, a multiband actuation system may be used where two or more transducers each deliver sounds within certain frequencies. Also, the assembly may also utilize the sensation of directionality via the conducted vibrations to emulate directional perception of audio signals received by the user. Another feature may include the ability to vibrationally conduct ancillary audio signals to the user along with primary audio signals.