Complex Tones Research Articles

Psychophysical Response for Intensity Variation in Pure Tone Sound - Attention & Retention Assessment in Human Beings

Background/Objectives: Human brain learns from conditioning. Also learning is an inherent activity exhibited by every human being. A better training/conditioning leads to a better learning and in remembering as well. Methods/Statistical Analysis: The present work focuses on the assessment of behavioural response for a predefined set of single tone sound with varying intensity after being conditioned for 20 days and after a break period of 7 days and assessing the same on day 28 for the retention based behavioural response. A pure tone complex of 1 KHz, 500 milliseconds duration was used and the test was conducted in the morning and evening in a noise free environment. A total of 44 subjects, both males and females of 20–30 years of no known auditory pathological history were considered. Findings: The results showed a distinct betterment of the auditory perception over the training period hinting at the attention abilities of the subjects. After a break of seven days, substantial information gained during the training phase was found to be retained thereby proving the retention abilities of the individuals. The presently obtained results provide a cue towards the learning abilities of human beings with gradual training and also to the extent to which the human beings can retain the aspects learnt during the training sessions. The results also demonstrated that the males have a better attention as well as retention abilities than females. Application/Improvements: The presently designed protocol is successfully able to assess the attention and retention based abilities of the individuals. This method can be extended to assess the auditory temporal resolution of professionals in case of basket ball and table tennis sports and also to assess the deterioration of the hearing perception of traffic police and the workers of fabrication and chemical industries.

Intracranial Electrophysiology of Auditory Selective Attention Associated with Speech Classification Tasks.

Auditory selective attention paradigms are powerful tools for elucidating the various stages of speech processing. This study examined electrocorticographic activation during target detection tasks within and beyond auditory cortex. Subjects were nine neurosurgical patients undergoing chronic invasive monitoring for treatment of medically refractory epilepsy. Four subjects had left hemisphere electrode coverage, four had right coverage and one had bilateral coverage. Stimuli were 300 ms complex tones or monosyllabic words, each spoken by a different male or female talker. Subjects were instructed to press a button whenever they heard a target corresponding to a specific stimulus category (e.g., tones, animals, numbers). High gamma (70–150 Hz) activity was simultaneously recorded from Heschl’s gyrus (HG), superior, middle temporal and supramarginal gyri (STG, MTG, SMG), as well as prefrontal cortex (PFC). Data analysis focused on: (1) task effects (non-target words in tone detection vs. semantic categorization task); and (2) target effects (words as target vs. non-target during semantic classification). Responses within posteromedial HG (auditory core cortex) were minimally modulated by task and target. Non-core auditory cortex (anterolateral HG and lateral STG) exhibited sensitivity to task, with a smaller proportion of sites showing target effects. Auditory-related areas (MTG and SMG) and PFC showed both target and, to a lesser extent, task effects, that occurred later than those in the auditory cortex. Significant task and target effects were more prominent in the left hemisphere than in the right. Findings demonstrate a hierarchical organization of speech processing during auditory selective attention.

(A)tonality in the Compositional Language of Peter Klatzow: A Triadic Study with an Added Note

ABSTRACTThis article adopts a triadic study to the exploration of (a)tonality in Peter Klatzow's compositional language. Firstly, academic scholarship on tonality, modality and atonality in the composer's oeuvre is summarised from a literary perspective. This is followed by an analysis of a more recent work, Sur une route toute blanche, dans un immense paysage (2010). An interview with Klatzow on questions concerning tonality constitutes the final section. It is concluded that the tonal practices of Klatzow's youth were replaced by avant-garde experimentation and atonal writing in the mid-1960s. The composer developed a unique voice in the late 1970s, characterised by the use of small intervallic cells, and the juxtaposition of tonal and atonal elements. A rapprochement of tonality in Klatzow's compositional language has been evident since the late 1980s, with a preference for modal and octatonic material, and without the complete abandonment of atonal practices. The compositional language of Sur une route toute blanche, dans un immense paysage can be considered neo-tonal in many respects. Consonant triads embellished with added notes are placed within non-functional, quasi-tonal frameworks. The compositional process is regulated by linearly combined pitch collections, while pedal notes, ostinatos and pitch emphases create a sense of tonal centrality. Klatzow believes that conventional tonal and modal practices are modified and extended into greater tonal complexes in his writing.

Infant pitch perception: Missing fundamental melody discrimination.

Although recent results show that 3-month-olds can discriminate complex tones by their missing fundamental, it is arguable whether they are discriminating on the basis of a perceived pitch. A defining characteristic of pitch is that it carries melodic information. This study investigated whether 3-month-olds, 7-month-olds, and adults can detect a change in a melody composed of missing fundamental complexes. Participants heard a seven-note melody and learned to respond to a change that violated the melodic contour. To ensure that participants were responding on the basis of pitch, the notes in the melody had missing fundamentals and varied in spectral content on each presentation. In experiment I, all melodies had the same absolute pitch, while in experiment II, the melodies were randomly transposed into one of three different keys on each presentation. Almost all participants learned to ignore the spectral changes and respond to the changed note of the melody in both experiments, strengthening the argument that complex tones elicit a sense of musical pitch in infants. These results provide evidence that complex pitch perception is functional by 3 months of age.

Possessive Tone in Tswefap (Bamileke): Paradigmatic or Derivational?

In this paper I consider two analyses of the possessive pronoun tonal paradigm in Tswefap, a Bamileke language spoken in Batoufam, Cameroon. As in the case of related languages that have been previously described, Tswefap has a rather complex tone system that involves multiple tone heights, tonal contours, and tone alternations. Although simplified, it also maintains several of the inherited noun class distinctions. In this study attention is on the tones of possessive pronouns and their effects on a preceding modified noun. I first present a paradigmatic account as one might find in a descriptive or pedagogical grammar indicating which possessive pronouns receive which tones. I then turn to a more traditional Bamileke and Grassfields Bantu analysis in terms of underlying representations and floating tones. It is argued that all possessive pronouns are preceded by a floating L tone which affects a preceding mid tone noun in one of two ways, depending on the syllable shape of the pronoun: (i) if the pronoun begins with a consonant, the mid of the noun becomes a mid to low contour tone; (ii) if the pronoun has consists solely of a vowel, the mid is raised to a high tone. Although I argue for the latter analysis, I conclude by demonstrating that alternate tonal variations indicate on-going change which may ultimately undermine the more abstract phonological analysis in favor of a considerably simplified paradigmatic tone assignment.

A quick behavioral dichotic word test is prognostic for clinical response to cognitive therapy for depression: A replication study

There are no commonly used clinical indicators of whether an individual will benefit from cognitive therapy (CT) for depression. A prior study found right ear (left hemisphere) advantage for perceiving dichotic words predicted CT response. This study replicates this finding at a different research center in clinical trials that included clinically representative samples and community therapists. Right-handed individuals with unipolar major depressive disorder who subsequently received 12–14 weeks of CT at the University of Pittsburgh were tested on dichotic fused words and complex tones tests. Responders to CT showed twice the mean right ear advantage in dichotic fused words performance than non-responders. Patients with a right ear advantage greater than the mean for healthy controls had an 81% response rate to CT, whereas those with performance lower than the mean for controls had a 46% response rate. Individuals with a right ear advantage, indicative of strong left hemisphere language dominance, may be better at utilizing cognitive processes and left frontotemporal cortical regions critical for success of CT for depression. Findings at two clinical research centers suggest that verbal dichotic listening may be a clinically disseminative brief, inexpensive and easily automated test prognostic for response to CT across diverse clinical settings.

Midbrain Synchrony to Envelope Structure Supports Behavioral Sensitivity to Single-Formant Vowel-Like Sounds in Noise.

Vowels make a strong contribution to speech perception under natural conditions. Vowels are encoded in the auditory nerve primarily through neural synchrony to temporal fine structure and to envelope fluctuations rather than through average discharge rate. Neural synchrony is thought to contribute less to vowel coding in central auditory nuclei, consistent with more limited synchronization to fine structure and the emergence of average-rate coding of envelope fluctuations. However, this hypothesis is largely unexplored, especially in background noise. The present study examined coding mechanisms at the level of the midbrain that support behavioral sensitivity to simple vowel-like sounds using neurophysiological recordings and matched behavioral experiments in the budgerigar. Stimuli were harmonic tone complexes with energy concentrated at one spectral peak, or formant frequency, presented in quiet and in noise. Behavioral thresholds for formant-frequency discrimination decreased with increasing amplitude of stimulus envelope fluctuations, increased in noise, and were similar between budgerigars and humans. Multiunit recordings in awake birds showed that the midbrain encodes vowel-like sounds both through response synchrony to envelope structure and through average rate. Whereas neural discrimination thresholds based on either coding scheme were sufficient to support behavioral thresholds in quiet, only synchrony-based neural thresholds could account for behavioral thresholds in background noise. These results reveal an incomplete transformation to average-rate coding of vowel-like sounds in the midbrain. Model simulations suggest that this transformation emerges due to modulation tuning, which is shared between birds and mammals. Furthermore, the results underscore the behavioral relevance of envelope synchrony in the midbrain for detection of small differences in vowel formant frequency under real-world listening conditions.

Uninformative dynamic visual stimuli aid in segregating two similar acoustic stimuli, but not in detecting a single stimulus in noise

Both the comprehension and detection of speech in noise are improved when the listener sees the talker’s mouth. There are multiple reasons for this, from basic physical temporal correlations to higher order linguistic cues; we have recently performed several experiments investigating the former. They were based on artificial stimuli with speech-like dynamics but no linguistic information. Auditory stimuli were a tone or tone complex with randomly modulated amplitude. Visual stimuli were a disc with a randomly modulated radius. We manipulated the correlation between the visual stimulus and each auditory stimulus. In all experiments, the visual stimulus provided no information about the task. In the first study, we presented two competing auditory stimuli and had listeners respond to events in the target stimulus (brief pitch or timbre fluctuations). Performance was better when the visual stimulus matched the auditory target than when it matched the masker. The second study employed a two-interval two-alter...

Effects of aging on the absolute pitch judgment and frequency following responses of electroencephalograms

Absolute pitch (AP) possessors can name the pitch class of the note simply by hearing a periodic tone. It has been reported that the AP judgment can shift by one or two semitones when AP possessor become old. We confirmed this age-related AP shift by a series of psychophysical experiments with piano sounds as well as synthesized complex tones. AP possessors whose ages ranged from 20s to 50s participated in the experiments. The results showed that the aged participants were likely to assign the higher pitch classes than young participants for the piano sounds. Similar tendencies were observed for the synthesized, complex sounds if they contained lower order harmonics. The hearing levels, OAEs, and the frequency following responses (FFRs) of the EEG were also measured for the same participants. The hearing levels and OAE levels which could be indices in the cochlear mechanical properties could not explain the age-related AP shift. The phase locking values of the FFRs obtained at 98 and 220 Hz could neither be a good predictor of the AP shift. Although no plausible model to predict it exists, the age-related AP shift might bring another route of overlooked hearing problems.

Effect of harmonic structure of notes on categorical chord perception

This paper reports distinct differences among the harmonic structures of notes on chord perception. Experimental results clarified that the existence of harmonics greatly improved chord perception accuracy. Subjective tests were conducted for 20 combinations of three notes from a minor chord to a major chord. The fundamental notes and the highest notes were fixed. The fundamental frequency of the middle note was shifted at an equal interval on the log scale. The harmonic structure was based on saw-tooth wave. The categorical perception accuracies were compared between pure tone and complex tone including five harmonics. The fundamental notes were C5 (523.3 Hz), A5 (880 Hz), and C7 (2093 Hz). The stimuli were diotically presented at 60 dB(SPL) through electro-static headphones. The subjects were requested to answer major or minor with the 2AFC method. The categorical perception accuracy was extremely low in case of C7 without harmonics. The percent corrects were as low as 46.7% and 54.8% for Cm and C, respectively. The Cm and C percent accuracies with harmonics were as high as 77.3% and 79.5%. The Cm and C accuracies were 97.7% and 93.2% for C5. The perceived categories turned from minor to major in the region between 8th and 15th note combinations.

Psychophysical evaluation of auditory signals in passenger vehicles

Twenty-one experienced drivers were recruited for the evaluation of sounds of four functions (horn, indicator, door open warning, and parking sensor) made by 11 car brand names. Each participant was required to evaluate all of the above sound signals by a pair-comparison test. After the comparison test, each participant was shown his/her pair-comparison result and was asked to comment on their preference and appropriateness of a sound. The physical properties and interview data were compared and summarized to propose design recommendations. Our results indicate that complex tones and a fundamental frequency between 500 and 1000 Hz were most preferred for horns while for indicators the preferred sounds had a higher dominant frequency. To reduce monotony, the indicators with double clicks and an OFF time interval of between 330 and 400 ms between two clicks were most preferred. Regarding door warning sounds, the waveform starting with a higher intensity then fading towards zero intensity is most preferred while for parking sensors, sounds beginning with a longer OFF time (about 500 ms) and having 3 or 4 distinctive tempo variations were most preferred. The relationship between pleasurability and pitch, loudness, and the tempo of sound signals basically followed an inverted-U function. Sound designers should avoid using very extreme parameter values when generating sound for a given function.

Frequency discrimination in the common marmoset (Callithrix jacchus)

The common marmoset (Callithrix jacchus) is a highly vocal New World primate species that has emerged in recent years as a promising model system for studies of auditory and vocal processing. Our recent studies have examined perceptual mechanisms related to the pitch of harmonic complex tones in this species. However, no previous psychoacoustic work has measured marmosets' frequency discrimination abilities for pure tones across a broad frequency range. Here we systematically examined frequency difference limens (FDLs), which measure the minimum discriminable frequency difference between two pure tones, in marmosets across most of their hearing range. Results show that marmosets' FDLs are comparable to other New World primates, with lowest values in the frequency range of ∼3.5–14 kHz. This region of lowest FDLs corresponds with the region of lowest hearing thresholds in this species measured in our previous study and also with the greatest concentration of spectral energy in the major types of marmoset vocalizations. These data suggest that frequency discrimination in the common marmoset may have evolved to match the hearing sensitivity and spectral characteristics of this species’ vocalizations.

Testing a spectral model of tonal affinity with microtonal melodies and inharmonic spectra

Tonal affinity is the perceived goodness of fit of successive tones. It is important because a preference for certain intervals over others would likely influence preferences for, and prevalences of, “higher-order” musical structures such as scales and chord progressions. We hypothesize that two psychoacoustic (spectral) factors—harmonicity and spectral pitch similarity—have an impact on affinity. The harmonicity of a single tone is the extent to which its partials (frequency components) correspond to those of a harmonic complex tone (whose partials are a multiple of a single fundamental frequency). The spectral pitch similarity of two tones is the extent to which they have partials with corresponding, or close, frequencies. To ascertain the unique effect sizes of harmonicity and spectral pitch similarity, we constructed a computational model to numerically quantify them. The model was tested against data obtained from 44 participants who ranked the overall affinity of tones in melodies played in a variety of tunings (some microtonal) with a variety of spectra (some inharmonic). The data indicate the two factors have similar, but independent, effect sizes: in combination, they explain a sizeable portion of the variance in the data (the model-data squared correlation is r2 = .64). Neither harmonicity nor spectral pitch similarity require prior knowledge of musical structure, so they provide a potentially universal bottom-up explanation for tonal affinity. We show how the model—as optimized to these data—can explain scale structures commonly found in music, both historical and contemporary, and we discuss its implications for experimental microtonal and spectral music.

EEG signatures accompanying auditory figure-ground segregation

In everyday acoustic scenes, figure-ground segregation typically requires one to group together sound elements over both time and frequency. Electroencephalogram was recorded while listeners detected repeating tonal complexes composed of a random set of pure tones within stimuli consisting of randomly varying tonal elements. The repeating pattern was perceived as a figure over the randomly changing background. It was found that detection performance improved both as the number of pure tones making up each repeated complex (figure coherence) increased, and as the number of repeated complexes (duration) increased – i.e., detection was easier when either the spectral or temporal structure of the figure was enhanced. Figure detection was accompanied by the elicitation of the object related negativity (ORN) and the P400 event-related potentials (ERPs), which have been previously shown to be evoked by the presence of two concurrent sounds. Both ERP components had generators within and outside of auditory cortex. The amplitudes of the ORN and the P400 increased with both figure coherence and figure duration. However, only the P400 amplitude correlated with detection performance. These results suggest that 1) the ORN and P400 reflect processes involved in detecting the emergence of a new auditory object in the presence of other concurrent auditory objects; 2) the ORN corresponds to the likelihood of the presence of two or more concurrent sound objects, whereas the P400 reflects the perceptual recognition of the presence of multiple auditory objects and/or preparation for reporting the detection of a target object.

The early component of middle latency auditory-evoked potentials in the process of deviance detection.

The aim of the present study was to investigate both the encoding mechanism and the process of deviance detection when deviant stimuli were presented in various patterns in an environment featuring repetitive sounds. In adults with normal hearing, middle latency responses were recorded within an oddball paradigm containing complex tones or speech sounds, wherein deviant stimuli featured different change patterns. For both complex tones and speech sounds, the Na and Pa components of middle latency responses showed an increase in the mean amplitude and a reduction in latency when comparing rare deviant stimuli with repetitive standard stimuli in a stimulation block. However, deviant stimuli with a rising frequency induced signals with smaller amplitudes than other deviant stimuli. The present findings indicate that deviant stimuli with different change patterns induce differing responses in the primary auditory cortex. In addition, the Pa components of speech sounds typically feature a longer latency and similar mean amplitude compared with complex tones, which suggests that the auditory system requires more complex processing for the analysis of speech sounds before processing in the auditory cortex.

Theta oscillations accompanying concurrent auditory stream segregation

The ability to isolate a single sound source among concurrent sources is crucial for veridical auditory perception. The present study investigated the event-related oscillations evoked by complex tones, which could be perceived as a single sound and tonal complexes with cues promoting the perception of two concurrent sounds by inharmonicity, onset asynchrony, and/or perceived source location difference of the components tones. In separate task conditions, participants performed a visual change detection task (visual control), watched a silent movie (passive listening) or reported for each tone whether they perceived one or two concurrent sounds (active listening). In two time windows, the amplitude of theta oscillation was modulated by the presence vs. absence of the cues: 60–350ms/6–8Hz (early) and 350–450ms/4–8Hz (late). The early response appeared both in the passive and the active listening conditions; it did not closely match the task performance; and it had a fronto-central scalp distribution. The late response was only elicited in the active listening condition; it closely matched the task performance; and it had a centro-parietal scalp distribution. The neural processes reflected by these responses are probably involved in the processing of concurrent sound segregation cues, in sound categorization, and response preparation and monitoring. The current results are compatible with the notion that theta oscillations mediate some of the processes involved in concurrent sound segregation.

Learning Pitch with STDP: A Computational Model of Place and Temporal Pitch Perception Using Spiking Neural Networks.

Pitch perception is important for understanding speech prosody, music perception, recognizing tones in tonal languages, and perceiving speech in noisy environments. The two principal pitch perception theories consider the place of maximum neural excitation along the auditory nerve and the temporal pattern of the auditory neurons’ action potentials (spikes) as pitch cues. This paper describes a biophysical mechanism by which fine-structure temporal information can be extracted from the spikes generated at the auditory periphery. Deriving meaningful pitch-related information from spike times requires neural structures specialized in capturing synchronous or correlated activity from amongst neural events. The emergence of such pitch-processing neural mechanisms is described through a computational model of auditory processing. Simulation results show that a correlation-based, unsupervised, spike-based form of Hebbian learning can explain the development of neural structures required for recognizing the pitch of simple and complex tones, with or without the fundamental frequency. The temporal code is robust to variations in the spectral shape of the signal and thus can explain the phenomenon of pitch constancy.

Mandarin Tone Identification in Cochlear Implant Users Using Exaggerated Pitch Contours.

To determine whether exaggerating the variations in fundamental frequency (F0) contours of Mandarin-based pitch fluctuations could improve tone identification by cochlear implant (CI) users. Twelve normal-hearing (NH) listeners and 11 CI users were tested for their ability to recognize F0 contours modeled after Mandarin tones, in 4- or 5-alternatives forced-choice paradigms. Two types of stimuli were used: computer-generated complex tones and voice recordings. Four contours were tested with voice recordings: flat, rise, fall, and dip. A fifth contour, peak, was added for complex tones. The F0 range of each contour was varied in an adaptive manner. A maximum-likelihood technique was used to fit a psychometric function to the performance data and extract threshold at 70% accuracy. As F0 range increased, performance in tone identification improved but did not reach 100% for some CI users, suggesting that confusions between contours could always be made even with extremely exaggerated contours. Compared with NH participants, CI users required substantially larger F0 ranges to identify tones, on the order of 9.3 versus 0.4 semitones. CI users achieved better performance for complex tones than for voice recordings, whereas the reverse was true for NH participants. Confusion matrices showed that the "flat" tone was often a default option when the tone contour's F0 range presented was too narrow for participants to respond correctly. These results demonstrate markedly impaired ability for CI users to identify tonal contours, but suggest that the use of exaggerated pitch contours may be helpful for tonal language perception.

Release from masking in cochlear-implant listeners and its relationship to spectro-temporal resolution

Release from masking is commonly observed in normal-hearing listeners when fluctuating interferers mask speech perception less than steady interferers at the same signal-to-noise ratio. In contrast, studies of cochlear-implant listeners have historically failed to find masking release with fluctuating maskers. Here, we provide new insights into the relationship between spectro-temporal resolution and release from masking in cochlear-implant and simulated cochlear-implant listeners. Varying degrees of current spread were simulated in normal-hearing listeners using a tone vocoder. Speech reception thresholds were measured with four different interferers: a tone complex, speech-shaped noise, four-talker babble, and a single competing talker. A dynamic spectral ripple detection test was conducted to measure psychophysical spectro-temporal resolution. Results show that overall speech perception was correlated with spectro-temporal ripple detection thresholds. However, some maskers were more sensitive to spectro-temporal resolution than others. Subjects in both groups demonstrated release from masking between the speech-shaped noise and the single competing talker conditions, and the degree of release varied with spectro-temporal ripple sensitivity. These findings shed new light on previous cochlear-implant results, suggesting that individual cochlear-implant listeners with high spectro-temporal resolution may benefit from the temporal fluctuations in certain noise types.

Tone and Phonation in Southeast Asian Languages

AbstractSoutheast Asia is often considered a quintessentialSprachbundwhere languages from five different language phyla have been converging typologically for millennia. One of the common features shared by many languages of the area is tone: several major national languages of the region have large tone inventories and complex tone contours. In this paper, we suggest a more fine‐grained view. We show that in addition to a large number of atonal languages, the tone languages of the region are actually far more diverse than usually assumed, and employ phonation type contrasts at least as often as pitch. Along the same lines, we argue that concepts such astoneandregister, while descriptively useful, can obscure important underlying similarities and impede our understanding of the behavior of phonetic properties, typological regularities, and diachrony. We finally draw the reader's attention to some issues of current interest in the study of tone and phonation in Southeast Asia and describe some technical developments that are likely to allow researchers to address new lines of research in years to come.