Measuring RMS Voltage: Many Meters Will Do

By Pat Brown

Pat Brown measures RMS Voltage using 5 difference meters and shares the results.

The Vrmsmax loudspeaker power test requires real-time measurement of the Root-Mean-Square (RMS) voltage of the noise stimulus. RMS measurements have been the subject of controversy since some variables regarding meter integration time, bandwidth, etc. exist. I have see excellent correlation between true RMS meters for noise signals. All meters shown here were used to measure 8Vrms of IEC noise during a recent power test on a line array HF element. The differential in measured RMS level between all of the meters is less than 0.5dB – adequate accuracy for loudspeaker power testing.

If the RMS voltage is still in doubt, I suppose one could use a thermometer. pb


RMS Voltage - Meter #1



RMS Voltage - Meter #2 Dorrough



RMS Voltage - Meter #3 Tenma


RMS Voltage - Meter #4

RMS Voltage - Meter #4



RMS Voltage - Meter #5