Acoustic reconfiguration devices and methods

A quick-disconnect passive acoustic cover, comprising:

• a first acoustic input port, a first acoustic channel having at least one first aperture remote from the first input port to define a Helmholtz resonator coupled to the first input port;
• a second acoustic input, a second acoustic channel having at least one second aperture remote from the second input port to define a Helmholtz resonator coupled to the second input port wherein:
• the cover is configured to be removably attachable to a portable audio device having a speaker and including a first audio output port having a first acoustic load for the speaker and a second audio output port having a second acoustic load for the speaker, the portable audio device including the speaker having a first system frequency response;
• wherein the first acoustic input port of the cover is configured to receive audio output from the speaker through the first audio output port of the portable audio device and the second acoustic input port of the cover configured to receive audio output from the second audio output port of the portable audio device, and
• wherein the acoustic cover is configured to redefine the acoustic load so as to replace the first system frequency response with a second system frequency response when removably attached to the portable audio device.