Comparison of vu-meter-based and rms-based calibration of speech levels.

A difference of approximately 5 dB exists between the level of spoken English determined using the ANSI standard vu-meter method compared to the common root-mean-square (rms) method. If the rms method is substituted for the present ANSI standard method for calibrating a speech audiometer, for example, the reported speech reception thresholds will improve 5 dB: Speech levels read approximately 5 dB less using rms. Similarly, the reported signal-to-noise ratio required to understand speech in a speech-spectrum noise will be 5 dB better using rms. A simple method for obtaining a close approximation to traditional calibrations using a modified rms method is given.