Sound :: essays research papers

Basis of Processing Sound Strategies Introduction to Coding StrategiesD.J. AllumCoding strategies define the way in which acoustic survives in our world are transformed intoelectrical signals that we can understand in our school principal. The practice-hearing person already has away to code acoustic sounds when the inner ear (cochlear) is functioning. The cochlea is thesensory organ that transforms acoustic signals into electrical signals. However, a deaf persondoes not have a functioning cochlea. The cochlear imbed takes over its function. Technically,it is relatively easy to send electrical current through implanted electrodes. The more difficultpart is to make the electrical signals carry the detach information about speech and othersounds. This responsibility is taken over by coding strategies. The more efficient the codingstrategy, the better the possibility that the brain will interpret the information as havingmeaning. Without meaning, sound is only unwanted noise.Some basic vocabulary is useful in understanding coding strategiesFrequency. name and address is composed of a range of frequencies from high-frequency sounds(sss, piii) to low-frequency sounds (ah). These frequencies also occur for sounds in ourenvironment. The speech-frequency range is from about 250 Hz to 6,000 Hertz (Hz). Amplitude. The amount of amplitude, or intensity, defines how loud a sound is heard.The usual range from the softest to the loudest sound is about 30 dB. The normal rangefor human hearing is around 120 dB. Tonotopic. A special characteristic of the cochlea and the audile nerve. It means thatthe apical region of the cochlea (and the nerve near this region) is more sensitive to lowfrequencies and that the basal region is more sensitive to high-frequencies. Therelationship between the intimately basal to the most apical region is a progression fromhigh-to-low frequency sensitivity. Filters. Filters are used to divide, electronically, acoustic signals into different ranges.For instance, for a speech-frequency range of 4,000 Hz, we could divide the enumerate rangeby 10 and each filter would hold 400 Hz. Stimulation Rate. The number of times an electrode is turned on and off, i.e., activatedwith electrical stimulation. The normal cochlea is like a series of filters. Sounds that have high-frequencies will fall intofilters at the basal end of the cochlea and those with low-frequencies will fall into filters in theapical end, i.e., in a tonotopic arrangement. Since the cochlea cannot accomplish this for adeaf person, the cochlear implant takes its place. It is important to remember that the auditorynerve is tonotopic even if the cochlea cannot transmit information because of deafness.