As may be used in connection with frequency-modulated (FM) radio systems and receivers processing FM broadcast transmissions, exemplary aspects are directed to a method may be performed by the receiver circuitry to receive FM broadcast signaling within a particular bandwidth for which a plurality of target channels are to have a specified channel spacing. The method may include: assessing detected energy for a first adjacent channel having the specified channel spacing and having a frequency immediately adjacent to a targeted one of the plurality of target channels; and discerning whether the detected energy is associated with ultra-sonic energy in detected modulation energy (e.g., ultra-sonic noise in an MPX signal), and/or is associated with modulation energy (e.g., due to over-modulation) from a second adjacent channel also having such specified channel spacing.