Melodic Query Input for Music Information Retrieval Systems - Intelligent Music Information Systems: Tools and Methodologies - page 69

Figure 3. Average performed pitch intervals vs.
stimulus intervals for each group (MUSI, BTWN,
NONM) in Experiment 3

widely. The plots for the BTWN and NONM
groups look similar but demonstrate even more
variation and contour errors. Figure 3 plots the
average performed interval size for each of the
three groups on the same graph.
Table 6 shows the correlation ( r ) values be-
tween stimulus interval and performed interval
for each individual subject, each group and all
subjects together. The correlation was computed
first for the entire set of intervals and then a
second time including only the smaller intervals
of seven semitones or less. We expected to see
better correlation values when considering only
these smaller intervals, as they seemed likely to
be easier to reproduce.

Discussion

Table 6. Correlation of performed intervals with
stimulus intervals for all subjects in Experiment 3

Lindsay's LIN-M group of musician subjects
performed significantly better than our MUSI
group in their respective studies. We had hoped
to attribute some of this difference to the two
subjects in Lindsay's study who were trained
vocally. However, further study of the results
Lindsay reported for each of his five individual
subjects demonstrated that the scores belonging
to these two subjects did not score significantly
higher than the other three. The differences may
instead be due to the small sample sizes for each
study.
The correlation scores of the BTWN and
NONM groups are nearly identical to one another
but below those of the MUSI group. While it
might be expected that the correlation values
would be higher when considering only intervals
in the range ±7 semitones, the opposite is true
for 8 of the 13 subjects, and in the MUSI group
as a whole.
Another interesting observation is that the
three subjects who scored most poorly came from

Correlation ( r )
All Intervals

Subject

Intervals ≤ ± 7

1 0.91 0.88

2 0.69 0.58

3 0.87 0.91

12 0.79 0.79

14 0.92 0.80

MUSI 0.83 0.80

8 0.90 0.93

9 0.80 0.80

11 0.89 0.91

13 0.42 0.33

BTWN 0.75 0.74

4 0.87 0.82

6 0.84 0.84

7 0.81 0.75

10 0.55 0.69

NONM 0.75 0.77

ALL 0.78 0.77