Wang-Bilger, 1973

Here are some confusion matrices from the paper by Marilyn DeMorrest Wang and Robert Bilger, "Consonant Confusions in Noise", JASA 54(5):1248-66.

The files are all ASCII readable. They are also PHONMAT-readable. Here's how you would read them in Matlab:

> blah = phonmat ('cv1main_wb.dat');
> blah.total

 pm (object of type PHONMAT) = 

    title: Consonant Confusions in CV utterances, summed over V = /iau/, noise levels and S/N ratios (Wang & Bilger 1973, Table II)
    Phones involved: 16, namely p t k b d g f T (th) s S (sh) v D (dh) z Z (zh) J (ch) _ (dz) 

       p    t    k    b    d    g    f    T    s    S    v    D    z    Z    J    _       Total
    p  933  210  191  16   16   47   98   39   30   17   11   10   26   16   14   24    p 1698
    t  245  843  213  35   67   31   68   30   46   25   22   11   12   12   29   24    t 1713
    k  324  247  565  30   35   53   89   27   39   40   24   8    15   7    97   102   k 1702
    b  136  60   68   486  60   25   191  126  65   5    316  104  33   6    5    9     b 1695
    d  33   56   33   178  819  133  53   34   46   11   94   78   62   17   14   42    d 1703
    g  20   22   20   82   148  938  15   12   20   12   132  29   57   37   7    162   g 1713
    f  198  88   69   91   40   9    765  168  113  19   48   42   28   6    4    11    f 1699
    T  107  67   69   107  25   13   667  275  204  29   58   32   29   4    12   14    T 1712
    s  44   38   34   51   38   25   150  70   905  57   70   29   157  14   13   15    s 1710
    S  26   37   51   17   31   38   26   13   84   870  12   8    34   35   288  130   S 1700
    v  34   20   37   204  43   52   84   65   43   13   705  193  155  23   4    27    v 1702
    D  37   30   18   239  82   64   49   67   56   10   534  270  192  12   9    28    D 1697
    z  20   22   23   72   58   115  31   32   41   12   231  114  787  68   3    84    z 1713
    Z  19   20   24   32   66   286  19   22   16   16   77   38   137  420  6    502   Z 1700
    J  67   149  92   15   20   14   46   24   144  221  13   8    16   15   829  37    J 1710
    _  20   21   12   30   73   152  8    6    18   39   34   8    106  148  11   1016  _ 1702

The phones involved sometimes have brackets; these indicate alternative (and usually more understandable) phoneme labels. For example, _ means 'dz' as in the middle of the word 'measure'. The one-character labels are, for reasons best called 'historical accident', in CELEX DISC format.

The Wang-Bilger experiments investigated consonant confusions in American English VC and CV syllables. There are 24 and 19 such consonants respectively. Listeners in the experiments recorded their responses by pushing buttons on preprinted boards. However, the only boards available were 4x4 ones, so the experimenters split each of the CV and VC syllable sets into two, and compiled separate confusion matrices for each.

CV was split into

VC was split into

There were also two types of experiment, a 'control' and a 'main' one. 'Control' is something of a misnomer, since it was more a preliminary experiment than a 'placebo' one.

The control experiment for each type of syllable stimulus (e.g. /p/ in CV) involved 156 tokens of that syllable played to each of 6 listeners, for a total of 936 responses. It was done to get a feeling of appropriate signal levels when no noise was present. The 156 tokens comprised 12 syllables presented at each of 13 noise levels. The 12 syllables were evenly split among 3 vowels, e.g. 4 were /pa/, 4 were /pi/ and 4 were /pu/.

The main experiment for each type of syllable stimulus involved 432 tokens of that syllable played to each of 4 listeners for a total of 1728 stimuli. The 432 tokens comprised 18 syllables presented at each of 6 S/N and 4 noise levels. The 18 syllables were also evenly split among the same 3 vowels as in the control experiment.

For reasons I don't understand, not all the rows sum to the same number. First I thought that was because some responses were not recorded. However, the sum of all sums of all rows comes out to a nice round number, suggesting (as does a line or two in the paper) that stimuli were actually not equally distributed, only approximately so. Therefore the figures of 156 and 432 should be taken as approximations.

These figures were manually typed from the paper and double-checked. Still, use only for preliminary experiments, and get a copy of the original paper to check them.