Cubic difference tones form from summed wavelets traveling to a characteristic place
Evidence
The nonlinear preprocessing model with active feedback in the inner ear was described in Sect. 3.1.5. Not only two-tone suppression can be treated in detail in a hardware model consisting of 150 sections each with a nonlinear feedback loop, but also the creation of the cubic (2h - h)-difference tone. The basic data are the level and phase distributions along the sections produced in this system by single tones. An enhancement is created at medium and low input levels through the activity of the nonlinear feedback loops, which results in a more sharply peaked level-place pattern. These patterns become much less peaked (“de-enhancement”) for high input levels. At high levels, the level and phase distributions along the sections are very similar to those produced by the linear passive system (feedback loop switched off). The creation of (2h - h)-difference tones is based on the same nonlinear effect. In this case, two tones are used as input. The de-enhancement produced by the additional tone is described as a gain reduction in the saturating nonlinearity of the feedback loop, as a consequence of increasing input levels. In each section, difference-tone wavelets are created that travelthereby changing level and phase - to their characteristic place, where they add up to the vector sum corresponding to the audible difference tone. In the ca”e of cancellation, the vector sum has to be compensated by an additional tone of the same frequency and magnitude but of opposite phase. Based on this strategy for treating (2h - h)-difference tones, the relevant levels of the difference-tone wavelets and the corresponding pha”es can be picked up at each section. This is done for two examples in the following paragraphs. Additionally, the vector sum of the wavelets that clearly illustrates the development of minima in the (2h - h)-cancellation tone versus level L1 of the lower primary is also shown. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1589
Categorization
Category: Causal Relationships
- DEFINE: Clarifies ‘enhancement’ vs ‘de-enhancement’ of level-place patterns and the traveling-wavelet model of difference-tone formation.
Related
- Phase differences among wavelets reduce the total difference-tone amplitude (similarity 0.82)
- Cubic difference tones arise inside the ear, not in the equipment (similarity 0.81)
- Cubic difference tones in hearing defy regular nonlinear transfer models (similarity 0.80)
- Quadratic difference tones measured by cancellation originate primarily in the middle ear. (similarity 0.80)
- Noise-induced high-frequency threshold shifts can make previously inaudible difference tones audible (similarity 0.79)
- Cancellation equalizes internally produced combination tones with an external tone (similarity 0.78)
- Difference noise generated by ear nonlinearities can be heard before the test tone itself (similarity 0.78)
- Cubic difference tones reveal nonlinear cochlear mechanics even at low sound levels (similarity 0.78)
- Combination tones arise from the hearing system’s own nonlinearity (similarity 0.78)
- Vector phase differences, not amplitudes, determine cancellation tone levels (similarity 0.78)
Broader Connections
- Wavelets from different cochlear regions can nearly cancel each other out
#complicates(0.85) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1612 - Phase differences among wavelets reduce the total difference-tone amplitude
#complicates(0.82) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1599 - Sound spectrum analysis depends on banks of filters to decompose signals
#expands(0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 464 - Cubic difference tones arise inside the ear, not in the equipment
#expands(0.72) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3355