Loudspeaker Measurements

With the cooperation of Canada's National Research Council (NRC), in the year 2000 the SoundStage! Network began measuring and publishing objective measurements of loudspeaker products.

What these measurements means is described here.


The waterfall is a 3D representation of the speakers' response to a wide-bandwidth signal that stops instantaneously. The Y-axis is level in dB, the X-axis is frequency from 200Hz to 20kHz, and time runs from back to front on the Z-axis (measurement constraints limit the length of time window available as frequency falls). The waterfall plots therefore illustrate how good the speakers are at switching off, and the Z-axis plot for a notional 'perfect speaker' would be empty. Any signals within the plot occurring after zero time represent the decay of mechanical or acoustic resonances. This is output that the speaker adds to the intended signal, colouring the sound and effectively degrading the signal-to-noise ratio.

Phil Ward


  1. Loudspeaker Measurements - SoundStage!
  2. MONITORS versus HI-FI SPEAKERS - Phil Ward