PSYC 230 Assignment (Tritone Paradox)

Name: ______R#: ______

Background: The pitch class circle , or chromatic circle , (see figure) represents all of the musical notes (pitch classes) within a musical octave. A tritone is any pair of notes on opposite sides of the circle (e.g., C-F#, C#-G) and a semitone is any note pair that is not diametrically opposite (e.g., C-C#, C-B). When a musical notes is played so that it contains frequencies in all octaves, it is a Shepard tone . Normally, when you play two musical notes in succession, you can easily tell whether they are ascending or descending in pitch; however, this is not so with Shepard tones. When tritone pair of Shepard tones is played in succession, it may be difficult to tell whether the notes are ascending or descending in pitch. For example, while one person may hear C-F# ascend in pitch, another person may hear it descend in pitch. Thus, the pitch class circle is oriented uniquely for any individual, but the note at the top represents the first note in a tritone pair that a person always perceives to be descending in pitch.

Purpose: To familiarize you with auditory perception and pitch change by constructing a pitch class circle. A discussion of the tritone illusion is here http://philomel.com/musical_illusions/tritone.php

Task: We will do the demonstration in class. The CD that I will play contains a series of tritone pairs played in succession. Listen to each tritone pair. Some pairs will sound ascending in pitch, others will sound descending in pitch. Your task is to decide whether the second note in each pair sounds higher or lower than the first. You will first hear a set of practice pairs as examples. I will play sixteen groups of tritone pairs with each group containing twelve tritone pairs.

After each tritone pair is played, in Table 1, in the cell coinciding with the current group and tritone pair; place an arrow indicating whether you perceive the tritone pair to ascend or descend in pitch. If ascending, draw an upward-pointing arrow or if descending draw a downward-pointing arrow.

Table 1 Group Number Group Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7

Tritone Pair 8 9 10 11 12

PSYC 230 Assignment (Tritone Paradox)

Data Analysis: Table 2 lists the first note from each tritone played. For example, for the first tritone pair from group 1, the first tone was G#, meaning the second tone was D.

Table 2 Group Number Group Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 G# B E G# E B C G# E C B G# C E B C 2 F A F# F F# A A# F F# A# A F A# F# A A# 3 G C# A G A C# D G A D C# G D A C# D 4 E E C E C E F E C F E E F C E F 5 C# G D C# D G G# C# D G# G C# G# D G G# 6 D C B D B C F# D B F# C D F# B C F# 7 A# G# G A# G G# D# A# G D# G# A# D# G G# D# 8 C F D# C D# F G C D# G F C G D# F G Tritone Pair 9 D# D# F D# F D# E D# F E D# D# E F D# E 10 B F# G# B G# F# C# B G# C# F# B C# G# F# C# 11 A D A# A A# D A A A# A D A A A# D A 12 F# A# C# F# C# A# B F# C# B A# F# B C# A# B

To analyze your data, in Table 1 locate tritone pairs that you perceived to Table 3 descend in pitch (down-pointing arrows). For those pairs, place the letter of Group Number the note from the same cell in Table 2 next to that downward pointing arrow 1 2 3 in Table 1. This is demonstrated for groups 1-3 in Table 3. You do not list 1 ↑ ↓ B ↑ the first note for tritone pairs you perceived to ascend in pitch. 2 ↑ ↑ ↓ F# 3 ↑ ↓ C# ↑ 4 ↑ ↓ E ↑ 5 ↓ C# ↑ ↑ 6 ↓ D C ↑ 7 ↓ A# ↑ ↓ G Tone Pair 8 ↓ C ↑ ↑ 9 ↓ D# ↓ D# ↓ F 10 ↓ B ↑ ↑ 11 ↑ ↓ D ↓ A# 12 ↑ ↓ A# ↓ C# When finished, count the number of times each tritone pair was perceived to descend, that is, count up the number of C’s, C#’s, D’s, etc. that you listed in Table 1. Use Table 4 below to record your frequencies.

Table 4 Tritone Pair: C-F# C#-G D-G# D#-A E-A# F-B F#-C G-C# G#-D A-D# A#-E B-F Pitch class of C C# D D# E F F# G G# A A# B first tone:

Totals:

Turn In: Use Table 4 to construct your own pitch class circle. To do so, draw a figure like the one on the preceding page, but do not list the note names yet. Using Table 4, locate the tritone pair that was perceived to descend in most frequently. This note is placed at the top position in the pitch-class circle. For example, if D had the greatest frequency, D goes at the top position (if there is a tie, choose the note closest to C). To fill in the rest of the pitch- class circle, in a clockwise manner fill in successively higher tones. For example, if D is at the top, D# will be listed next, then then E, then F, and so on. Below each tone list the frequency from the data in Table 4.