Explanation for PowerBook G4 speaker balance issues

Yesterday we reported on an apparent issue where fading the balance slider on the audio controls of some PowerBook G4 models resulted in sound seemingly coming from the left speaker no matter what the setting. In other words, if a user slides the balance completely to the right speaker, audio still emanates from the left side of the PowerBook.

This is actually caused by the presence of a third, "mid-range" speaker that is located toward the left side of the PowerBook. This speaker is always active whether the balance is shifted to the left or right, providing the perception of error in balance control.

As stated on the PowerBook specifications page, 12-inch and 15-inch models sport "built-in stereo speakers with midrange-enhancing third speaker"

MacFixIt reader Herbert M. Schaltegger comments: "If one is critically concerned with precise placement of a sound source within a stereo field, use of small, internal laptop speakers is not the ideal solution anyway - external near-field monitor speakers or monitor headphones is a much more appropriate solution. Given that this 'problem' does not exist with use of headphones or external speakers, it does not appear to be significant to this owner."

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