Methods and apparatus to enforce a power off state of an audience measurement device during shipping

A method of enforcing a reduced power state in an audience measurement device during shipping of the device, comprising:

• receiving an audio signal from a sensor indicative of a noise level outside the audience measurement device;
• determining a frequency spectrum associated with the received audio signal;
• determining an energy level in a first frequency band of the determined frequency spectrum;
• determining an energy level in a second frequency band of the determine frequency spectrum, wherein the second frequency band is higher than the first frequency band;
• calculating a difference between the energy of the first frequency band and the energy of the second frequency band;
• comparing the difference between the energy of the first frequency band and the energy of the second frequency band to a muffling threshold;
• and
• transitioning the audience measurement device to a reduced power state if the difference between the energy of the first frequency band and the energy of the second frequency band is greater than the muffling threshold.

A machine readable medium having instructions stored thereon that, when executed by a processor, cause a machine to:

• receive an audio signal from a sensor indicative of a noise level outside the audience measurement device;
• determine a frequency spectrum associated with the received audio signal;
• determine an energy level in a first frequency band of the determined frequency spectrum;
• determine an energy level in a second frequency band of the determine frequency spectrum, wherein the second frequency band is higher than the first frequency band;
• calculate a difference between the energy of the first frequency band and the energy of the second frequency band;
• compare the difference between the energy of the first frequency band and the energy of the second frequency band to a muffling threshold;
• and
• power off at least a portion of the audience measurement device if the difference between the energy of the first frequency band and the energy of the second frequency band is greater than the muffling threshold.