Sequential stimulus presentation sets the JND test while simultaneous tones reveal finer differences

Evidence

Experimentally, the JND is found by playing one stimulus after the other and asking listeners to indicate if they can hear a difference. If the stimuli were presented together, listeners would be able to detect a much finer difference because they would be able to hear beats (see Section 2.2). In that case, there is the potential for listeners to be able to detect differences right down to the point where the frequencies of the sine waves are identical and the beats disappear; this is the basis upon which musical instruments are tuned. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 866

Categorization

• QUESTION: Why do simultaneous tones allow finer discrimination than sequential ones — and is tuning genuinely done down to zero beats, or is there a practical floor?
• XREF: Connects to the earlier chapter discussion of beats (Section 2.2) — worth remembering as a mechanism that separately powers both tuning and JND limits. — connects to: Presented together, tones reveal far finer pitch differences via beats than sequential comparison; Simultaneously presented tones sharpen pitch discrimination down to beat disappearance; Manipulating envelope and fine structure separately reveals their competing roles in tone perception. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3384

Broader Connections

• Presented together, tones reveal far finer pitch differences via beats than sequential comparison #corroborates (0.92)
• Simultaneously presented tones sharpen pitch discrimination down to beat disappearance #expands (0.88)
• Manipulating envelope and fine structure separately reveals their competing roles in tone perception. #qualifies (0.75) — Dijk, Pim van, Physiology, Psychoacoustics and…, 3384