Two simultaneous pure tones generate an audible tone at their difference frequency
Evidence
Calculate the difference tone and first four combination tones that occur when pure tones of 1200 Hz and 1100 Hz sound simultaneously Equation 5.2 gives the difference tone frequency = fh−fl = 1200 − 1100 = 100 Hz. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1582
Categorization
- CANDY: Play two sine tones 100 Hz apart and a third ghost tone appears that isn’t in the signal — an easy demo to share.
- DEFINE: Crystallizes the difference-tone formula fh minus fl with a worked numeric example.
- XREF: connects to: Two tones presented together generate an audible combination (difference) tone not physically present. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 773; Two simultaneous tones generate audible lower tones absent from the stimulus — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1571; Two tones presented together produce audible combination tones in the ear — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 330 (+17 more)
Broader Connections
- Two tones presented together generate an audible combination (difference) tone not physically present.
#corroborates(1.00) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 773 - Two simultaneous tones generate audible lower tones absent from the stimulus
#corroborates(1.00) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1571 - Two tones presented together produce audible combination tones in the ear
#corroborates(1.00) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 330 - Two close sine tones produce amplitude beats at their frequency difference
#contradicts(1.00) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 574 - Two frequencies can mechanically generate sum and difference frequencies in the ear
#corroborates(1.00) - Two simultaneous pure tones may fuse rather than be heard separately.
#complicates(1.00) - High-frequency tones yield multiple possible source locations from a single phase difference
#complicates(1.00) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1467 - A true difference tone is audible even from inharmonic partials separated by 200 Hz
#corroborates(1.00) — Eric J. Heller, Why You Hear What You Hear- An…, 2300 - Combination tones exist below both source tones and vary in audibility
#corroborates(1.00) - A healthy cochlea emits new frequencies when stimulated by two tones
#complicates(1.00) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2727 - Beating between two high-frequency tones can create a phantom low-frequency tone
#corroborates(1.00) — Eric J. Heller, Why You Hear What You Hear- An…, 2223 - Two ear sounds can differ in phase while differing little in amplitude.
#complicates(1.00) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1625 - Peak dissonance between two tones occurs at a quarter critical band separation
#complicates(1.00) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1291 - Pure-tone instruments readily produce audible combination tones
#corroborates(1.00) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1621 - Combination tones arise from the hearing system’s own nonlinearity
#expands(1.00) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 430