Opportunities for modeling the air channel of the behavior system

The possibility of applying low-frequency simplifications in the modeling of the external auditory canal is analyzed. The specified frequency range of reliability of representation of distributed environmental parameters by lumped elements in the form of mass and flexibility of air, closed in the volume of the channel. For calculations of the input resistance is considered the external channel of the hearing aid of a person in length 27 mm and a width of 7 mm. The method of research is based on the calculation of the frequency dependence of the input resistance of the auditory channel in the simulation of it in the form of a four-pole, namely, the T-shaped narrow channel scheme with elements described by hyperbolic functions of the channellength wave form. The obtained values of the resonance and antiresonance frequencies of the input resistance practically coincide with the values obtained from the theoretical solution of the wave equation of the channel. Most of the existing modern models of the middle and outer ears are based on the presentation of channels in the form of electroacoustic schemes composed of lumped elements. When modeling the auditory channel using a T-shaped circuit whose elements are represented by lumped parameters: in the case of a closed channel, the frequencies of antiresonance and harmonics of resonant frequencies are lost; there is a resonance frequency shift (4,1 kHz instead of 6 kHz), no antiresonance frequency and harmonic resonant frequencies in an open channel. Such results are duet of the fact that, in this case, the range of low-frequency simplifications is limited to a frequency of 3 kHz (and with a more severe restriction in general at a frequency of about 400 Hz), which significantly reduces the range of reliable calculations. The modeling of the auditory channel with only lumped mass elements and flexibility leads to the absence off requency response characteristics of the channel of harmonics of resonance and antiresonance frequencies, which can play a significant role in the combination of channel models and the auditory systemas a whole. In this connection, it is necessary to compare the calculations of the frequency characteristics of the channels according to the full and simplified characteristics. Ref. 11, fig. 8.