fig5 illustrates an example architecture for one preferred embodiment of the simplified fitting system , showing its components . the personal computer 501 runs the simplified fitting software 502 . the function of the fitting software 502 is to control the generation and presentation of the musical notes , accept responses from the listener 508 , and automatically create a customised fitting for the sound processing device 504 , and download it to the device 504 . the personal computer 501 communicates with the sound processing device 504 via the programming interface 503 . the musical notes are generated 505 within the sound processing device 504 . the resultant note is converted to an acoustic signal and presented to the listener 508 under the control of the fitting software 502 . fig1 illustrates an exemplary amplitude envelope of a musical note 505 generated by the sound processing device 504 . the amplitude envelope is determined by the onset time 101 , the sustain time 102 , the offset time 103 and the decay time 104 . the parameters help to determine the loudness and timbre of the sound . typical onset times 101 are in the range 10 to 100 ms , and preferably in the range 25 to 60 ms ; typical sustain times 102 are in the range 0 to 1000 ms , and preferably in the range 200 to 500 ms ; and typical offset times 103 are in the range 50 to 1500 ms , and preferably in the range 300 to 1000 ms . the decay time 104 is the time for the sound to decay exponentially to 1 / e of its maximum level . the decay time 104 is typically 50 to 2000 ms , and preferably in the range 100 to 700 ms . fig2 illustrates an exemplary filter shape with low frequency cutoff 201 and high frequency cutoff 202 , which are used to set the frequency characteristics of the filter including its bandwidth 203 . in a preferred embodiment , the filter cut - off frequencies are varied to create filters centred around the audiological frequencies of interest 250 , 500 , 1000 , 1500 , 2000 , 3000 , 4000 , 6000 hz , and with bandwidths in the range ⅙ to 1 octave , and preferably in the range ¼ to ½ octave . more or fewer frequencies of interest may be chosen , as may other values . fig3 illustrates a square wave waveform used to generate a musical sound . the square wave is characterised by its period 301 and its amplitude 302 . typically , the frequency of the square wave would be 50 to 500 hz , to provide harmonics spacing at 50 to 500 hz intervals . preferably , the frequency spacing of the harmonics is in the range 100 to 300 hz . the amplitude of the musical notes is easily controlled by changing the amplitude 302 of the square wave . fig4 illustrates an exemplar spectrum of a musical note consisting of three tones 401 centred about a frequency of interest 403 at 1500 hz and spaced at 125 hz 402 . the number of tones 401 may be in the range 2 to 10 , preferable in the range 3 to 5 . in a preferred embodiment , the frequencies of interest 403 are the audiological frequencies 250 , 500 , 1000 , 1500 , 2000 , 3000 , 4000 , 6000 hz . more or fewer frequencies of interest 403 may be chosen , as may other values . the spacing of frequencies 402 may be in the range 50 to 500 hz , preferably in the range 100 to 300 hz . in a preferred embodiment , the frequency spacing 402 is 125 hz for frequencies of interest 401 up to 1000 hz and 250 hz for frequencies of interest above 1000 hz . the amplitude of the tones may be equal or unequal . one preferred embodiment is shown in fig5 . the simplified fitting software 502 , running on the computing device 501 controls the output of musical notes from the sound processing device 504 by sending control parameters including the number 401 , frequencies , and amplitudes of the tones making up the notes via the programming interface 503 to the sound processing device 504 . the listener 508 hears a sequence of musical notes of differing frequency and is instructed to adjust the loudness of the individual notes until they are equal and comfortable in loudness . once the musical notes have been balanced in loudness , the simplified fitting software calculates a customised fitting for the sound processing device 504 using the balanced note levels to determine the frequency response and other parameters of the fitting . the customised fitting is loaded and saved into the sound processing device 504 via the programming interface 503 . in alternative embodiments of the invention , the musical notes are generated in the personal computer 501 and transmitted electrically from the computer 501 to the sound processing device 504 . in a second preferred embodiment of the invention the functions of the computing device 501 are performed by a mobile phone handset . in this embodiment no programming interface device 503 is needed . in a third preferred embodiment of the invention shown in fig6 , a mobile phone handset is the customizable sound processing device 601 as well as the computing device 601 that runs the simplified fitting software 602 . in this case , the musical notes are generated in the mobile phone handset 605 , and the frequency response and other characteristics of the phone output are optimised for the listener by using the loudness balanced output levels of the musical notes . some portions of this detailed description are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory . these algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art . an algorithm is here , and generally , conceived to be a self - consistent series of steps leading to a desired result . the steps are those requiring physical manipulations of physical quantities . usually , though not necessarily , these quantities take the form of electrical or magnetic signals capable of being stored , transferred , combined , compared , and otherwise manipulated . it has proven convenient at times , principally for reasons of common usage , to refer to these signals as bits , values , elements , symbols , characters , terms , numbers , codes , or the like . as such , it will be understood that such acts and operations , which are at times referred to as being computer - executed , include the manipulation by the processing unit of the computer of electrical signals representing data in a structured form . this manipulation transforms the data or maintains it at locations in the memory system of the computer , which reconfigures or otherwise alters the operation of the computer in a manner well understood by those skilled in the art . the data structures where data are maintained are physical locations of the memory that have particular properties defined by the format of the data . however , while the invention is described in the foregoing context , it is not meant to be limiting as those of skill in the art will appreciate that various of the acts and operations described may also be implemented in hardware . it should be borne in mind , however , that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities . unless specifically stated otherwise as apparent from the description , it is appreciated that throughout the description , discussions utilizing terms such as “ processing ” or “ computing ” or “ calculating ” or “ determining ” or “ displaying ” or the like , refer to the action and processes of a computer system , or similar electronic computing device , that manipulates and transforms data represented as physical ( electronic ) quantities within the computer system &# 39 ; s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage , transmission or display devices . it will be appreciated by persons skilled in the art that numerous variations and / or modifications may be made to the invention as shown in the specific embodiments without departing from the scope of the invention as broadly described . the present embodiments are , therefore , to be considered in all respects as illustrative and not restrictive .
in one embodiment , a method for customising a sound processing device for an individual listener including presentation of one or more sounds to the listener directly from the sound processing device , each sound comprising a collection of two or more harmonically related tones , spectrally positioned about a frequency of interest , and having a temporal envelope consisting of a rise time , sustain time , and decay time , obtaining information from the listener , adjusting the level of the sounds , and using the adjusted levels to set up the sound processing device for the listener .