A scale of the percentage of the articulation loss of consonants. A formula derived by V.M.A. Peutz based on distance, RT60, Volume of air in the room, the N factor, and the Q of the source. A measure of how difficult it is to understand someone in a room. The lower the number, the better for speech intelligibility.

Alcons means Percentage Articulation Loss of Consonants = %ALcons. This machine measure of intelligibility is closely associated with the TEF sound analyzer. It is computed from measurements of the Direct-to-Reverberant Ratio and the Early Decay Time using a set of correlations defined by SynAudCon, and is specified in percent.