> Step by step

5. Statistics

1 At the bottom of the SPAN interface, the Statistics section displays a range of historic data relating to all channels making up the currently selected Channel Group – so that’s left and right for the Default Stereo Group, for example, or front left, front right, rear left, rear right, centre and LFE for 5.1 Surround. To reset the Statistics fields, click the Reset button.

2 The RMS field shows the unweighted RMS level in decibels, calculated continuously until the Reset button is next hit. SPAN doesn’t show peak RMS values, but it does calculate them in the background using a 50ms window. The Max Crest Factor field shows the difference between RMS and peak RMS, so to work out the peak RMS, you simply add the two values together. 3 The Clippings field reveals the number of samples exceeding 0dBFS (ie, digital clipping) since the last reset, while Peak displays the level of the loudest single sample in the input signal – ie, the absolute peak level of your source material at the highest possible resolution. 4 The Correlation Meter features two data points: the horizontal meter shows the phase relationship between the first two channels in the selected Group. At 1, the channels are perfectly in phase; at -1 they’re 180º out of phase; and at 0, they’re half way between. 5 The Correlation Meter’s R/L field represents the volume difference between the first two channels over the last three seconds in decibels: a negative value means the first channel (left in a stereo pair) is louder by that value, while a positive value means the second channel (right) is louder. 6 Ten metering types are accessible via the Metering menu. dBFS, dBFS.30 and dBFS.15 simply raise the lower limit of the output meter scale from -60dB to -15dB. dBFS+3 boosts the RMS output metering by 3dB, and the six K options are Bob Katz’s K-System biasing modes, which we’ll leave you to research in your own time.