Loudness evaluations of electric clock noise

The noise from consumer electric clocks was studied to evaluate loudness estimating procedures. Eight different clock noises were tape recorded for presentation to a panel of people for loudness judgments. An electronic switch enabled the recorded clock noise and a 1000 Hz tone to be presented alternately via earphones for $\text{1}\text{2}$-sec durations with $\text{1}\text{2}$-sec silences between signals. The subjects adjusted the 1000 Hz tone to match the loudness of the clock noise. It was determined that Stevens' MARK VI procedure generally underestimates the observed loudness, but is usually less than 10 phons in error. It is possible that biasing effects had some influence on this result. If ranking on a relative loudness scale is all that is desired, dB(A) measurements will suffice. However, the dB(A) measurements do underestimate the differences in loudness between the quietest and loudest clocks.