6. An apparatus for measuring a resemblance between a plurality of sound samples, comprising: a learning means, including: means for acoustically analyzing a reference sound sample using a p.sup.th order acoustical analysis to obtain a resultant vector signal of the reference sound sample; means for calculating a covariance matrix X of size p.times.p using the resultant vector signal of the reference sound sample; means for inverting said covariance matrix X to obtain an inverted covariance matrix X.sup.-1 ; and means for storing the inverted covariance matrix X.sup.-1 in a dictionary; a test means, including: means for acoustically analyzing a test sound sample using a p.sup.th order acoustical analysis to obtain a resultant vector signal of the test sound sample; means for calculating a covariance matrix Y of size p.times.p using the resultant vector signal of the test sound sample; means for multiplying the covariance matrix Y with the inverted covariance matrix X.sup.-1 to obtain a product YX.sup.-1 ; means for calculating p eigenvalues .lambda.k of YX.sup.-1 ; means for determining a resemblance between the reference sound sample and the test sound sample using generalized sphericity functions using at least two of the following equations: ##EQU17## where a, g, and h represent respectively an arithmetic, geometric, and harmonic mean values of the eigenvalues .lambda.k, wherein the learning means and test means each include respective: means for amplifying the sound samples; means for filtering the amplified sound samples; and means for digitizing the filtered amplified sound samples.
7. An apparatus according to claim 6, wherein the means for determining a resemblance uses the trace of the matrix YX.sup.-1 : ##EQU18## the determinant of the matrix YX.sup.- : ##EQU19## and the trace of the inverted matrix YX.sup.- : ##EQU20## without having to explicitly calculate the eigenvalues .lambda.k.