Complex Tones Research Articles

Spectral weighting functions for localization of complex sound. III. The effect of sensorineural hearing lossa).

Spectral weighting functions for sound localization were measured in participants with bilateral mild sloping to moderately severe, high-frequency sensorineural hearing loss (SNHL) and compared to normal hearing (NH) participants with and without simulated SNHL. Each participant group localized three types of complex tones, comprised of seven frequency components spatially jittered and presented from the horizontal frontal field. A threshold-elevating noise masker was implemented in the free field to simulate SNHL for participants with NH. On average, participants with SNHL and NH (in quiet and simulated SNHL) placed the greatest perceptual weight on components within the interaural time difference "dominance region," found previously to peak around 800 Hz [Folkerts and Stecker, J. Acoust. Soc. Am. 151, 3409-3425 (2022)]. In addition to the peak at 800 Hz, both participant groups (including NH participants in quiet) placed near equal weight on 400 Hz, resulting in a broadened "peak" in the dominance region, most likely due to the reduction of audibility to higher frequency components. However, individual weighting strategies were more variable across participants with SNHL than participants with NH. Localization performance was reduced for participants with SNHL but not for NH participants with simulated hearing loss when compared to NH participants in quiet.

Generating Sonic Phantoms with Quadratic Difference Tone Spectrum Synthesis

Abstract Quadratic difference tones belong to a family of perceptual phenomena that arise from the neuromechanics of the auditory system in response to particular physical properties of sound. Long deployed as “ghost” or “phantom” tones by sound artists, improvisers, and computer musicians, in this article we address an entirely new topic: How to create a quadratic difference tone spectrum (QDTS) in which a target fundamental and harmonic overtone series are specified and in which the complex tone necessary to evoke it is synthesized. We propose a numerical algorithm that solves the problem of how to synthesize a QDTS for a target distribution of amplitudes. The algorithm aims to find a solution that matches the desired spectrum as closely as possible for an arbitrary number of target harmonics. Results from experiments using different parameter settings and target distributions show that the algorithm is effective in the majority of cases, with at least 99% of the cases being solvable in real time. An external object for the visual programming language Max is described. We discuss musical and perceptual considerations for using the external, and we describe a range of audio examples that demonstrate the synthesis of QDTSs across different cases. As we show, the method makes possible the matching of QDTSs to particular instrumental timbres with surprising efficiency. Also included is a discussion of a musical work by composer Marcin Pietruszewski that makes use of QDTS synthesis.

The Origin of the Dominant: Schoenberg's ‘Strong Progression’ and the Realisation of Implied Virtual Pitches

ABSTRACTIn major‐minor tonality, V implies I, and rising fourths, falling thirds and rising seconds between successive chord roots are more common than falling fourths, rising thirds and falling seconds respectively. Possible explanations involve history (in two‐part medieval counterpoint, harmonic major sixths resolved to octaves – maintained in V–I); the rising leading note (V–I includes it, IV–I does not); acoustic speculation (in V–I, the third harmonic of resolves to the second); voice leading (in V7–I, a tritone resolves to a third by contrary step); melodic closure (a rising melodic leap implies subsequent falling steps, and melodies often end with –, harmonised V–I); root newness (chords ‘progress’ if the second chord's root is not part of the first); and tonal stability (V is less stable than IV, giving it a stronger ‘urge’ to resolve). An additional possibility combines the ‘virtual‐pitch’ theory of Ernst Terhardt with the ‘implication‐realisation’ theory of Leonard B. Meyer and Eugene Narmour. Major and minor triads imply subsidiary virtual pitches (missing fundamentals; see Rameau's ‘fundamental bass’) at third and fifth intervals below the root. These weakly perceived pitches are realised in the next chord if the root falls by a third or rises a fourth or major second, creating a feeling of forward progression – while also facilitating intonation for singers and melodic instrumentalists. The theory correctly predicts that successive harmonic complex (but not pure) tones an octave apart sound more similar if rising, and rising octaves are more common than falling in melody. It also explains why Classical modulations are asymmetrical in the opposite direction, major keys tending to modulate to V (not IV) and minor to III (not VI): accidental flats tend to be more perceptually salient or stable than sharps.

Investigating the variation of intonation contours in Northern Vietnamese tones

Intonation is an instrument for structuring discourse and emphasizing different types of information. In German, for example, pitch is used to highlight focus, while in Vietnamese, different pitch contours distinguish lexical tones. As of yet, the interplay between intonation and lexical tone in relation to information structure has not been sufficiently investigated across languages. Vietnamese has six lexical tones and is particularly interesting for investigating the influence of different intonation strategies on the realization of tones. Here, we present a production study with 70 Northern Vietnamese speakers. The participants read six sentences under two conditions. In each sentence, a word occurring in the final position of the sentence and carrying one of the six tones was pronounced in two different discourse contexts. Acoustic analyses of the intonation contours showed that Vietnamese speakers realized the words with significant differences in pitch at the onset. Yet, the strategies for raising or lowering the pitch varied depending on the tone. Our results show the use of prosodic cues in a complex tone system across a large number of speakers. In addition, the study can serve as a starting point for educational programs that include training on intonation patterns in specific contexts.

Perceptual organization and task demands jointly shape auditory working memory capacity.

Listeners performed two different tasks in which they remembered short sequences comprising either complex tones (generally heard as one melody) or everyday sounds (generally heard as separate objects). In one, listeners judged whether a probe item had been present in the preceding sequence. In the other, they judged whether a second sequence of the same items was identical in order to the preceding sequence. Performance on the first task was higher for everyday sounds; performance on the second was higher for complex tones. Perceptual organization strongly shapes listeners' memory for sounds, with implications for real-world communication.

Profile analysis in the inferior colliculus: physiology and modeling studies

Profile-analysis is a strategy for assessing sensitivity to differences in spectral shape [Green, Oxford University Press, 1988]. Despite extensive behavioral data, the neuronal mechanisms underlying profile-analysis remain elusive. To bridge this gap, extracellular recordings were made in awake rabbit inferior colliculus (IC) and simulated using a computation model. The standard stimulus was a log-spaced, n-component, zero-phase, equal-amplitude complex tone, presented diotically. The central component was incremented in the target stimulus. The discharge rate as a function of characteristic frequency (CF) was inferred by shifting the stimulus spectrum past the CF of each neuron. When the increment frequency was near CF, IC neurons had rates that decreased as the increment increased, contradicting a simple energy-based code. In some cases, the differences between rates for target and standard were largest for stimuli with component spacing that yielded the lowest thresholds in listeners. Responses of IC neurons that were excited by amplitude-modulated stimuli were consistent with model predictions for profile-analysis stimuli [Maxwell et al., JASA 147, 3523 (2020), Guest et al., bioRxiv (2023)]; however, the models did not explain responses of other types of IC neurons. Potential factors contributing to this discrepancy, such as off-CF inhibition and chirp selectivity, will be further explored. Support: NIHR01-DC010813

A psychoacoustic test on the effect of masking on annoyance to urban air mobility vehicle noise

Urban Air Mobility (UAM) vehicles have a large range of designs and configurations that lead to new noise characteristics and potentially different perceptual responses when compared to traditional aircraft. In addition, UAM vehicles are expected to operate around and within densely populated regions where the presence of ambient background noise is often present. Strategically, this can be leveraged to inform vehicle design and operations to partially or completely mask UAM noise, allowing for mitigation of negative responses and an increased number of allowed operations. A psychoacoustic test was conducted to investigate how masking effects can influence the annoyance response to a low frequency harmonic tone complex (80-320 Hz). To do this, five test subjects compared their annoyance response to the low frequency tonal noise with a higher frequency broadband noise (10 dB down bandwidth between 300 and 2000 Hz), with and without a masking noise present. Detection thresholds were also measured for both sounds to help fit a model to the data. Although the effect of masking on annoyance is complex, results indicate that for some individuals, masking leads to a lower annoyance than the sound level alone would predict.

A spectro-temporal modulation test for predicting speech reception in hearing-impaired listeners with hearing aids

Spectro-temporal modulation (STM) detection sensitivity has been shown to be associated with speech-in-noise reception in hearing-impaired (HI) individuals. Based on previous research, a recent study [Zaar, Simonsen, Dau, and Laugesen (2023). Hear Res 427:108650] introduced an STM test paradigm with audibility compensation, employing STM stimulus variants using noise and complex tones as carrier signals. The study demonstrated that the test was suitable for the target population of elderly individuals with moderate-to-severe hearing loss and showed promising predictions of speech-reception thresholds (SRTs) measured in a realistic set up with spatially distributed speech and noise maskers and linear audibility compensation. The present study further investigated the suggested STM test with respect to (i) test-retest variability for the most promising STM stimulus variants, (ii) its predictive power with respect to realistic speech-in-noise reception with non-linear hearing-aid amplification, (iii) its connection to effects of directionality and noise reduction (DIR+NR) hearing-aid processing, and (iv) its relation to DIR+NR preference. Thirty elderly HI participants were tested in a combined laboratory and field study, collecting STM thresholds with a complex-tone based and a noise-based STM stimulus design, SRTs with spatially distributed speech and noise maskers using hearing aids with non-linear amplification and two different levels of DIR+NR, as well as subjective reports and preference ratings obtained in two field periods with the two DIR+NR hearing-aid settings. The results indicate that the noise-carrier based STM test variant (i) showed optimal test-retest properties, (ii) yielded a highly significant correlation with SRTs (R2=0.61) exceeding and complementing the predictive power of the audiogram, (iii) yielded significant correlation (R2=0.51) with the DIR+NR-induced SRT benefit, and (iv) did not provide significant correlation with subjective preference for DIR+NR settings in the field. Overall, the suggested STM test represents a valuable tool for diagnosing speech-reception problems that remain when hearing-aid amplification has been provided and the resulting need for and benefit from DIR+NR hearing-aid processing.

The software for improvement of image quality after enlargement

In the paper digital images of various formats were investigated. The different vector image formats have different color rendering capabilities. The main task was to achieve a result of refinement of the random low resolution color raster image without quality and resolution loss. The biggest advantage of using specific vector or compressed raster formats is the ability of scaling without quality loss and comparatively small file size. This eases vector images transfer through networks. In the article a specific algorithm of raster images refinement was investigated, particularly the method of raster images refinement based on combination of interpolation algorithms with and without square root of the color values. The key point of the method is comparison and combination of vertical, horizontal and diagonal interpolation that allows to achieve better precision on color depth calculation. This exact method was never used in commercial of scientific software though there are different variation of combined interpolation methods similar to current one. In this paper two different approaches to image matrix re-calculation during image refinement were tested, in order to research how root squaring the value of color depth would affect the target color value. The result shows that this approach allows to keep more details in shadows and save contours during interpolation though the images lose somewhat of color depth. The experiment shows that this interpolation method with square rooting color values allows to enlarge and refine color images with complex tone curve structure and keep details of the objects in place, though color depth is worsened especially in deepest shades and blacks. On the opposite the method of combined interpolation without root squaring gives significantly better result with color interpolation but loses details in the dark areas of the initial image. The suggested method can be used in a number of different areas

Benefits of Harmonicity for Hearing in Noise Are Limited to Detection and Pitch-Related Discrimination Tasks.

Harmonic complex tones are easier to detect in noise than inharmonic complex tones, providing a potential perceptual advantage in complex auditory environments. Here, we explored whether the harmonic advantage extends to other auditory tasks that are important for navigating a noisy auditory environment, such as amplitude- and frequency-modulation detection. Sixty young normal-hearing listeners were tested, divided into two equal groups with and without musical training. Consistent with earlier studies, harmonic tones were easier to detect in noise than inharmonic tones, with a signal-to-noise ratio (SNR) advantage of about 2.5 dB, and the pitch discrimination of the harmonic tones was more accurate than that of inharmonic tones, even after differences in audibility were accounted for. In contrast, neither amplitude- nor frequency-modulation detection was superior with harmonic tones once differences in audibility were accounted for. Musical training was associated with better performance only in pitch-discrimination and frequency-modulation-detection tasks. The results confirm a detection and pitch-perception advantage for harmonic tones but reveal that the harmonic benefits do not extend to suprathreshold tasks that do not rely on extracting the fundamental frequency. A general theory is proposed that may account for the effects of both noise and memory on pitch-discrimination differences between harmonic and inharmonic tones.

Study on suppression effect of air-conducted sound by bone-conducted sound

This paper proposes a method for suppressing air-conducted (AC) sound by presenting bone-conducted (BC) sound. First, the amplitude and phase of BC tones at six frequencies (250, 500, 1000, 2000, 4000, and 8000 Hz) were examined by using a method of limits to suppress AC tones presented via earphones. On the basis of the results of the first experiment, finite-impulse-response (FIR) filters, dependent upon participants, were then designed as "a compensation filter" to cancel out AC sound by presenting BC sound. Next, whether or not AC complex tones presented via earphones could be suppressed by simultaneously presenting BC complex tones compensated for by FIR filtering was investigated. Finally, whether or not this method could be applied to suppress stationary noise was also investigated. From these investigations, the proposed method was found to adequately suppress AC complex tones, and the average amounts of suppression for the AC and AC complex tones were approximately 5 and 1 dB, respectively. In addition, it was also shown that the proposed method can be used to suppress AC stationary noise but not greatly.

Confronting Loneliness with Devotion

Abstract Today, the practice of religion is strongly influenced by digitalisation, in not only everyday life but also liminal situations such as dying. Apps, social networks, and virtual church services offer believers opportunities for participation when their mobility is impaired due to ageing and severe illness. This short-term ethnography explores Bible (e-)reading and (religious) encounters in a palliative care unit of a Swiss hospital, drawing on in-depth interviews, participant observation, and documentary photography. Using the case of a devout Protestant, who was chosen as a case study from a sample of 12 terminally ill patients, I will investigate 1) the existential issues involved in the dying process, 2) how Bible (e-)reading alleviates these issues, and 3) the networks and encounters with which the practice is connected. The results show that anticipation of death in conjunction with personality and social issues bestow a complex emotional tone on the Christian’s end-of-life journey. Bible reading, performed both through mobile mediation and face-to-face with companions, is an avenue through which to gain strength and hope in this difficult situation. Another important finding is that the devotional practice involves an exchange of gifts, which transposes the practice into a moral economy of compassion and care.

Tone complexity and analyst forecast behaviors: evidence from earnings conference calls

PurposeBoth the SEC (Securities and Exchange Commission) and the popular press have routinely criticized firms for the complexity of their financial disclosures. This study aims to investigate how financial analysts respond to the tone complexity of firm disclosures.Design/methodology/approachUsing approximately 20,000 earnings conference call transcripts of S&P 1,500 firms between 2005 and 2015, the authors first calculate the abnormal negative tone, the measure of tone complexity; then use such tone measure in econometric models to examine analyst forecast behavior. The authors also test the robustness of the results under different model specifications, tone word lists and alternative tone measure calculations.FindingsConsistent with the notion that analysts respond to the information demand from investors and incur more costs and effort to analyze firm disclosure when the tone is more complex, the authors find that higher tone complexity is positively and significantly associated with more analyst following, longer report duration, more forecast revisions, larger forecast error and larger forecast dispersion. In addition, the authors find that tone complexity has a long-term impact on analyst following but has a limited long-term impact on analyst report duration, analyst revision, forecast error and dispersion.Originality/valueThis study complements existing literature by highlighting the information role of financial analysts and by providing evidence that analysts incorporate the management tone disclosed during conference calls to adjust their forecasting behaviors. The results can be used by policymakers as evidence and support for further improving firm communication from a new dimension of disclosure tone.

Cochlear Implant Users can Effectively Combine Place and Timing Cues for Pitch Perception.

The study objective was to characterize cochlear implant (CI) pitch perception for pure, complex, and modulated tones for frequencies and fundamental frequencies in the ecologically essential range between 110 and 440 Hz. Stimulus manipulations were used to examine CI users' reliance on stimulation place and rate cues for pitch discrimination. The study was a within-subjects design with 21 CI users completing pitch discrimination measures using pure, complex, and modulated tones. Stimulus manipulations were used to test whether CI users have better pitch discrimination for low-pass compared with high-pass filtered harmonic complexes, and to test whether they have better pitch discrimination when provided a covarying place cue when listening to amplitude-modulated tones. Averaged across conditions, participants had better pitch discrimination for pure tones compared with either complex or amplitude-modulated tones. Participants had better pitch discrimination for low-pass compared with high-pass harmonic complexes and better pitch discrimination for amplitude-modulated tones when provided a covarying place cue. CI users integrate place and rate cues across the ecologically essential pitch range between 110 and 440 Hz. We interpret the observed better pitch discrimination for low-pass compared with high-pass filtered harmonics complexes, and for amplitude-modulated tones when provided a covarying place cue, as evidence for the importance of providing place-of-excitation cues for fundamental frequencies below 440 Hz. Discussion considers how such encoding could be implemented with existing devices.

Simulation of hearing loss can induce pitch shifts for complex tones.

Most studies on pitch shift provoked by hearing loss have been conducted using pure tones. However, many sounds encountered in everyday life are harmonic complex tones. In the present study, psychoacoustic experiments using complex tones were performed on healthy participants, and the possible mechanisms that cause pitch shift due to hearing loss are discussed. Two experiments were performed in this study. In experiment 1, two tones were presented, and the participants were asked to select the tone that was higher in pitch. Partials with frequencies less than 250, 500, 750, or 1,000 Hz were eliminated from the harmonic complex tones and used as test tones to simulate low-tone hearing loss. Each tone pair was constructed such that the tone with a lower fundamental frequency (F0) was higher in terms of the frequency of the lowest partial. Furthermore, partials whose frequencies were greater than 1,300 or 1,600 Hz were also eliminated from these test tones to simulate high-tone hearing loss or modified sounds that patients may hear in everyday life. When a tone with a lower F0 was perceived as higher in pitch, it was considered a pitch shift from the expected tone. In experiment 2, tonal sequences were constructed to create a passage of the song "Lightly Row." Similar to experiment 1, partials of harmonic complex tones were eliminated from the tones. After listening to these tonal sequences, the participants were asked if the sequences sounded correct based on the melody or off-key. The results showed that pitch shifts and the melody sound off-key when lower partials are eliminated from complex tones, especially when a greater number of high-frequency components are eliminated. Considering that these experiments were performed on healthy participants, the results suggest that the pitch shifts from the expected tone when patients with hearing loss hear certain complex tones, regardless of the underlying etiology of the hearing loss.

Habituation of auditory responses in young autistic and neurotypical children.

Prior studies suggest that habituation of sensory responses is reduced in autism and that diminished habituation could be related to atypical autistic sensory experiences, for example, by causing brain responses to aversive stimuli to remain strong over time instead of being suppressed. While many prior studies exploring habituation in autism have repeatedly presented identical stimuli, other studies suggest group differences can still be observed in habituation to intermittent stimuli. The present study explored habituation of electrophysiological responses to auditory complex tones of varying intensities (50-80 dB SPL), presented passively in an interleaved manner, in a well-characterized sample of 127 autistic (MDQ = 65.41, SD = 20.54) and 79 typically developing (MDQ = 106.02, SD = 11.50) children between 2 and 5 years old. Habituation was quantified as changes in the amplitudes of single-trial responses to tones of each intensity over the course of the experiment. Habituation of the auditory N2 response was substantially reduced in autistic participants as compared to typically developing controls, although diagnostic groups did not clearly differ in habituation of the P1 response. Interestingly, the P1 habituated less to loud 80 dB sounds than softer sounds, whereas the N2 habituated less to soft 50 dB sounds than louder sounds. No associations were found between electrophysiological habituation and cognitive ability or participants' caregiver-reported sound tolerance (Sensory Profile Hyperacusis Index). The results present study results extend prior research suggesting habituation of certain sensory responses is reduced in autism; however, they also suggest that habituation differences observed using this study's paradigm might not be a primary driver of autistic participants' real-world sound intolerance.

Effect of diotic versus dichotic presentation on the pitch perception of tone complexes at medium and very high frequencies

Difference limens for fundamental frequency (F0), F0DLs, are usually small for complex tones containing low harmonics that are resolved in the auditory periphery, but worsen when the rank of the lowest harmonic increases above about 6–8 and harmonics become less resolved. The traditional explanation for this, in terms of resolvability, has been challenged and an alternative explanation in terms of harmonic rank was suggested. Here, to disentangle the effects of resolvability and harmonic rank the complex tones were presented either diotically (all harmonics to both ears) or dichotically (even and odd harmonics to opposite ears); the latter increases resolvability but does not affect harmonic rank. F0DLs were measured for 14 listeners for complex tones containing harmonics 6–10 with F0s of 280 and 1400 Hz, presented diotically or dichotically. For the low F0, F0DLs were significantly lower for the dichotic than for the diotic condition. This is consistent with a benefit of increased resolvability of harmonics for F0 discrimination and extends previous results to harmonics as low as the sixth. In contrast, for the high F0, F0DLs were similar for the two presentation modes, adding to evidence for differences in pitch perception between tones with low-to-medium and very-high frequency content.

Mathematical foundations of complex tonality

Equal temperament, in which semitones are tuned in the irrational ratio of , is best seen as a serviceable compromise, sacrificing purity for flexibility. Just intonation, in which intervals are given by products of powers of 2, 3, and 5, is more natural, but of limited flexibility. We propose a new scheme in which ratios of Gaussian integers form the basis of an abstract tonal system. The tritone, so problematic in just temperament, given ambiguously by the ratios , , , , none satisfactory, is in our scheme represented by the complex ratio . The major and minor whole tones, given by intervals of and , can each be factorized into products of complex semitones, giving us a major complex semitone and a minor complex semitone . The perfect third, given by the interval , factorizes into the product of a complex whole tone and its complex conjugate. Augmented with these supplementary tones, the resulting scheme of complex intervals based on products of low powers of Gaussian primes leads to the construction of a complete system of major and minor scales in all keys.

Assessing mechanisms of frequency discrimination by comparison of different measures over a wide frequency range

It has been hypothesized that auditory detection of frequency modulation (FM) for low FM rates depends on the use of both temporal (phase locking) and place cues, depending on the carrier frequency, while detection of FM at high rates depends primarily on the use of place cues. To test this, FM detection for 2 and 20 Hz rates was measured over a wide frequency range, 1–10 kHz, including high frequencies for which temporal cues are assumed to be very weak. Performance was measured over the same frequency range for a task involving detection of changes in the temporal fine structure (TFS) of bandpass filtered complex tones, for which performance is assumed to depend primarily on the use of temporal cues. FM thresholds were better for the 2- than for the 20-Hz rate for center frequencies up to 4 kHz, while the reverse was true for higher center frequencies. For both FM rates, the thresholds, expressed as a proportion of the center frequency, were roughly constant for center frequencies from 6 to 10 Hz, consistent with the use of place cues. For the TFS task, thresholds worsened progressively with increasing frequency above 4 kHz, consistent with the weakening of temporal cues.

Spectral weighting functions for localization of complex sound. II. The effect of competing noise.

Spectral weighting of sound localization cues was measured in the presence of three levels of competing noise presented in the free field. Target stimuli were complex tones containing seven tonal components, presented from an ∼120° range of frontal azimuths. Competitors were two independent Gaussian noises presented from 90° left and right azimuth at one of three levels yielding +9, 0, and -6 dB signal-to-noise ratio. Results revealed the greatest perceptual weight for components within the interaural time difference (ITD) "dominance region," which was found previously to peak around the 800-Hz component in quiet [Folkerts and Stecker (2022) J. Acoust. Soc. Am. 151, 3409-3425]. Here, peak weights were shifted toward lower-frequency components (i.e., 400 Hz) in all competing noise conditions. These results contradict the hypothesis of a shift in the peak weights toward higher frequencies based on previous behavioral localization performance in competing noise but are consistent with binaural cue sensitivity, availability, and reliability; measured low-frequency ITD cues within the dominance region were least disrupted by the presence of competing noise.