Below roughly 12.5 Hz the difference tone coincides with the beat frequency.
Evidence
Notice that this is the beat frequency when the frequency difference is less than approximately 12.5 Hz (see Chapter 2). The frequencies of other possible combination tones that can result from two pure tones sounding simultaneously can be calculated as follows: f f n ( ) [ ) [ ] = − − = − 1 1 1 n(f f f nf h d (5. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1574
Categorization
- XREF: Explicitly bridges to the Chapter 2 treatment of beating; a lineage marker for the book’s cumulative argument. — connects to: Perceived beat rate equals the frequency difference, not true waveform periodicity.; Two close sine tones produce amplitude beats at their frequency difference — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 574; Ear frequency response varies with amplitude, especially at low frequencies. (+15 more)
Broader Connections
- Perceived beat rate equals the frequency difference, not true waveform periodicity.
#corroborates(1.00) - Two close sine tones produce amplitude beats at their frequency difference
#qualifies(1.00) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 574 - Beat rate is set by frequency difference, not by the true tone periodicity.
#corroborates(1.00) — Eric J. Heller, Why You Hear What You Hear- An…, 2221 - Combination tones exist below both source tones and vary in audibility
#corroborates(0.90) - Ear frequency response varies with amplitude, especially at low frequencies.
#complicates(0.80) - Low-frequency tones become relatively louder as level increases.
#complicates(0.80) - Two coupled modes split above and below the test frequency, causing beat frequencies
#complicates(0.80) - Beating between two high-frequency tones can create a phantom low-frequency tone
#complicates(0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 2223 - A true difference tone is audible even from inharmonic partials separated by 200 Hz
#complicates(0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 2300 - Low-level tones mask lower frequencies more than higher ones, reversing at high levels
#complicates(0.80) - High frequencies pass toneholes more readily than low frequencies do
#complicates(0.80) - Low-pass noise is heard at a pitch matching its cut-off frequency
#complicates(0.80) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3281 - Difference noise generated by ear nonlinearities can be heard before the test tone itself
#complicates(0.80) - Low-frequency noise fluctuates audibly while high-frequency noise is steady
#complicates(0.80) - Removing low harmonics from a complex tone leaves its pitch unchanged.
#complicates(0.80) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1192