*pitch perception

5 stages of moores model

-Bank of bandpass filters -neural transduction -analysis of spike intervals -comparison of time intervals present across channels (to look for commonalties) -decision mechanism picks most prominent interval

Periodic complexes have 1.___ pitch is often assessed by 2.___ The pitch of a periodic complex ahs a pitch which 3.___

1. harmonics 2. pitch is often assessed by pitch matches with PT's. 3. closely corresponds to the fundimental freq. *this is problematic for the place theory but not the timing theory

pitch perception: What sis pitch perception the basis of? 1.____ Musical pitch can be described in terms of 2._____ Pitch perception depends primarily on 3.____

1. musical melody-variations in pitch give rise to the sensation of musical melody. 2. "tone hight" and "tone chroma" 3. freq, but its also influenced by amplitude envelope, duration and other factors

Musical intervals, scales and consonance: what are traditional musical scales based on? 1.___ other ratios: 2.__ Simple ration produce 3.__ some feel perception of music intervals comes from 4.__

1. octaves (2:1 ratio); the octave contains 12 semitones 2. fifth:3:2; major 3rd=5:4 3. pleasing or consonant sounds 4. early exposure to speech; also possible that pleasant percept is related to neural firing pattern

Beats perception is related to pitch perception. When 2 tones of similar freq (EX 500Hz and 504Hz) are sounded simultaneously 1.___

1. one tone of the average of the 2 (here 502hz) will be perceived. This tone will appear to wax and wane in loudness at a rate = to the difference btwn the 2 (here 4kHz)

what are the theories of pitch perception?

1. place theories- rely on the idea that sounds are analyzed spectrally by the tonotopic organization of the BM 2. temporal theories-rely on the timing pattern of neural pulses elicited by the sound

Temporal theory- Without stimulation, neurons 1.____ Once the neuron is stimulated 2.___ pitch perception depends on the 3.___

1. randomly fire 2. spikes are synchronized with the period of the signal for freq less than 5kHz 3. neural synchrony

Freq discrimination has been measured using a variety of methods including 1.____

1. the difference limen for freq (DLF) and the FM detection limen (FMDL) * the DLF is the smallest change in freq that can be reliably detected (JND)

Virtual pitch: when lower harmonics are removed from a periodic complex 1.___ what is this finding known as? 2.__

1. the pitch still corresponds to that of the missing fundimental 2. pitch of the missing fundimental, residue pitch, periodicity pitch, low pitch and virtual pitch * virtual pitch can be heard even in the presence of a masking noise at the fundimentlal freq (this is even more problematic for the place theory)

Freq DL: Generally, the DLF is 1.___ In the best, middle freq region, the DLF is 2.____

1. very small, getting slightly progressively smaller with increasing level 2. about .2% (proportion of center freq) and gets larger at higher & lower freq

what is "best beats" 1.___ As the level difference increases 2.___

1. when the intensity levels of the 2 tones is =, the beats will be greater (louder). 2. the level (loudness) of the beats decreases

neither place nor temporal theories can 1.___

1.fully account for itch perception both place & timing processes are involved with the relative importance of each dependent on the freq & sound type

Mel scale: Early work in pitch perception was done by SS stevens. the unit for subjective pitch was called 1.___ with the standard _____ the mel scale has very limited utility, but it does indicate that 2.____ and shows____

1a. the mel b. of 1000Hz at 40 phons (40 dBSPL) equivalent to 1000 mels. *the resulting scale of about 3500 mels covered the audible range 2a. pitch is not directly equivalent to freq change. b. a relationship to BM distance and critical bands

Virtual pitch: 2 groups of models-

Pattern recognition- freq analysis; pitch detection by freq of components temporal models- timing intervals btwn spikes

Moores model: moore describes a model which incorporates

both the pattern recognition models and he temporal models. *pitch perception involves more than place and a particular group of neurons

Pitch complexes: research suggests oitch perception for complexes may be

either an auditory pattern matching process (probably completed in the central auditory sys) or a temporal process

pitch of noise

high pass and low pass of noise with a step slope has a pitch quality, which sooresponds to the cut off freq of the filter *NB noise has a pitch quality similar to the center freq of the noise

Place theory- In tonotopic organization, HF tones produce 1._____ the perceived pitch of sinusoids cooresponds to 2.___

maximal displacements at the basal end of the cochlea and lF tones produce max displacements at the apical end (with corresponding neural tonotopic organization through the cortex) 2. the peripheral excitation patterns

Pitch of complexes: complexes can be

periodic or aperiodic

what is pitch defined as and what does it depend on?

that attribute of auditory sensation in terms of which sounds may be ordered on a scale extending from low to high. Pitch depends mainly on the freq content of the sound stimulus, but it also depends on the sound pressure and the waveform of the stimulus.

what have "best beats" been used to examine?

the cohclear distorition products (combo tones) but the methods has less success than the cancellation method)

Pitch & intensity: The early work of stevens found that as intensity increased 1.____

the pitch of a LF sound (<2K Hz) decreased but the pitch of a HF tone (>4kHz) increased *although later studies found a less dramatic influence of intensity on pitch, the general observation is still true