Root Mean Squared Explained

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Root_Mean_SquareI was confused this week as we discussed the 8 RMS output of the SuperTooth Disco sound bar we’re giving away from the episode Cheap Sunglasses. What the heck is Room Mean Squared? Alan knew what the acronym was, but not what it meant. G&B Listener Mark Wilson helps us non-electrical engineers with the explanation.

Root Mean Square is a mathematical formula that calculates the square root of the mean value of the squared values of the varying instantaneous power levels in the signal.  So… don’t worry about all of the math.  Just call it RMS and know that it represents the average/continuous power that your amplifier can output.  It’s a very good standardized way of comparing the power output of one amplifier to another in a manner that is consistent with normal hearing. Some manufacturers used to quote Peak power in their advertisements because that number was always larger.  You need that surge of power for a cymbal crash or some other loud transient in the audio.  However, the amplifier can’t sustain that level of output.  That’s why we use RMS instead.

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