Spectral Tilt Research Articles

기식 등급에 따른 CPP (Cepstral Peak Prominence) 분석 비교

The aim of this study is to synthesize pathological breathy voice and to make a cepstral peak prominence (CPP) table following breathiness ranks by cepstral analysis to supplement reliability of the perceptual auditory judgment task. KlattGrid synthesizer included in Praat was used. Synthesis parameters consist of two groups, i.e., constants and variables. Constant parameters are pitch, amplitude, flutter, open phase, oral formant and bandwidth. Variable parameters are breathiness (BR), aspiration amplitude (AH), and spectral tilt (TL). Five hundred sixty samples of synthetic breathy vowel /a/ for male were created. Three raters participated in ranking of the breathiness. 217 were proved to be inadequate samples from perceptual judgment and cepstral analysis. Finally, 343 samples were selected. These CPP values and other related parameters from cepstral analysis are classified under four breathiness ranks (B0~B3). The mean and standard deviation of CPP is <TEX>$16.10{\pm}1.15$</TEX> dB(B0), <TEX>$13.68{\pm}1.34$</TEX> dB(B1), <TEX>$10.97{\pm}1.41$</TEX> dB(B2), and <TEX>$3.03{\pm}4.07$</TEX> dB(B3). The value of CPP decreases toward the severe group of breathiness because there is a lot of noise and a small quantity of harmonics.

Using speech sounds to test functional spectral resolution in listeners with cochlear implants.

In this study, spectral properties of speech sounds were used to test functional spectral resolution in people who use cochlear implants (CIs). Specifically, perception of the /ba/-/da/ contrast was tested using two spectral cues: Formant transitions (a fine-resolution cue) and spectral tilt (a coarse-resolution cue). Higher weighting of the formant cues was used as an index of better spectral cue perception. Participants included 19 CI listeners and 10 listeners with normal hearing (NH), for whom spectral resolution was explicitly controlled using a noise vocoder with variable carrier filter widths to simulate electrical current spread. Perceptual weighting of the two cues was modeled with mixed-effects logistic regression, and was found to systematically vary with spectral resolution. The use of formant cues was greatest for NH listeners for unprocessed speech, and declined in the two vocoded conditions. Compared to NH listeners, CI listeners relied less on formant transitions, and more on spectral tilt. Cue-weighting results showed moderately good correspondence with word recognition scores. The current approach to testing functional spectral resolution uses auditory cues that are known to be important for speech categorization, and can thus potentially serve as the basis upon which CI processing strategies and innovations are tested.

Classification of lexical stress using spectral and prosodic features for computer-assisted language learning systems

We present a system for detection of lexical stress in English words spoken by English learners. This system was designed to be part of the EduSpeak® computer-assisted language learning (CALL) software. The system uses both prosodic and spectral features to detect the level of stress (unstressed, primary or secondary) for each syllable in a word. Features are computed on the vowels and include normalized energy, pitch, spectral tilt, and duration measurements, as well as log-posterior probabilities obtained from the frame-level mel-frequency cepstral coefficients (MFCCs). Gaussian mixture models (GMMs) are used to represent the distribution of these features for each stress class. The system is trained on utterances by L1-English children and tested on English speech from L1-English children and L1-Japanese children with variable levels of English proficiency. Since it is trained on data from L1-English speakers, the system can be used on English utterances spoken by speakers of any L1 without retraining. Furthermore, automatically determined stress patterns are used as the intended target; therefore, hand-labeling of training data is not required. This allows us to use a large amount of data for training the system. Our algorithm results in an error rate of approximately 11% on English utterances from L1-English speakers and 20% on English utterances from L1-Japanese speakers. We show that all features, both spectral and prosodic, are necessary for achievement of optimal performance on the data from L1-English speakers; MFCC log-posterior probability features are the single best set of features, followed by duration, energy, pitch and finally, spectral tilt features. For English utterances from L1-Japanese speakers, energy, MFCC log-posterior probabilities and duration are the most important features.

Blue-tilted tensor spectrum and thermal history of the Universe

We investigate constraints on the spectral index of primordial gravitational waves (GWs), paying particular attention to a blue-tilted spectrum. Such constraints can be used to test a certain class of models of the early Universe. We investigate observational bounds from LIGO+Virgo, pulsar timing and big bang nucleosynthesis, taking into account the suppression of the amplitude at high frequencies due to reheating after inflation and also late-time entropy production. Constraints on the spectral index are presented by changing values of parameters such as reheating temperatures and the amount of entropy produced at late time. We also consider constraints under the general modeling approach which can approximately describe various scenarios of the early Universe. We show that the constraints on the blue spectral tilt strongly depend on the underlying assumption and, in some cases, a highly blue-tilted spectrum can still be allowed.

Autocorrelation-Based Features for Speech Representation

This study investigates autocorrelation-based features as a potential basis for phonetic and syllabic distinctions. The work comes out of a theory of auditory signal processing based on central monaural autocorrelation and binaural crosscorrelation representations. Correlation-based features are used to predict monaural and binaural perceptual attributes that are important for the architectural acoustic design of concert halls: pitch, timbre, loudness, duration, reverberation-related coloration, sound direction, apparent source width, and envelopment (Ando, 1985, 1998; Ando and Cariani, 2009). The current study investigates the use of features of monaural autocorrelation functions (ACFs) for representing phonetic elements (vowels), syllables (CV pairs), and phrases using a small set of temporal factors extracted from the short-term running ACF. These factors include listening level (loudness), zero-lag ACF peak width (spectral tilt), τ1 (voice pitch period), φ1 (voice pitch strength), τe (effective duration of the ACF envelope, temporal repetitive continuity/contrast), segment duration, and Δφ1/Δt (the rate of pitch strength change, related to voice pitch attack-decay dynamics). Times at which ACF effective duration τe is minimal reflect rapid signal pattern changes that usefully demarcate segmental boundaries. Results suggest that vowels, CV syllables, and phrases can be distinguished on the basis of this ACF-derived feature set.

Computerized analysis of acoustic characteristics of patients with internal nasal valve collapse before and after functional rhinoplasty

Acoustic analysis of sounds produced during speech provides significant information about the physiology of larynx and vocal tract. The analysis of voice power spectrum is a fundamental sensitive method of acoustic assessment that provides valuable information about the voice source and characteristics of vocal tract resonance cavities. The changes in long-term average spectrum (LTAS) spectral tilt and harmony to noise ratio (HNR) were analyzed to assess the voice quality before and after functional rhinoplasty in patients with internal nasal valve collapse. Before and 3 months after functional rhinoplasty, 12 participants were evaluated and HNR and LTAS spectral tilt in /a/ and /i/ vowels were estimated. It was seen that an increase in HNR and a decrease in LTAS spectral tilt existed after surgery. Mean LTAS spectral tilt in vowel /a/ decreased from 2.37 ± 1.04 to 2.28 ± 1.17 (P = 0.388), and it was decreased from 4.16 ± 1.65 to 2.73 ± 0.69 in vowel /i/ (P = 0.008). Mean HNR in the vowel /a/ increased from 20.71 ± 3.93 to 25.06 ± 2.67 (P = 0.002), and it was increased from 21.28 ± 4.11 to 25.26 ± 3.94 in vowel /i/ (P = 0.002). Modification of the vocal tract caused the vocal cords to close sufficiently, and this showed that although rhinoplasty did not affect the larynx directly, it changes the structure of the vocal tract and consequently the resonance of voice production. The aim of this study was to investigate the changes in voice parameters after functional rhinoplasty in patients with internal nasal valve collapse by computerized analysis of acoustic characteristics.

Lyth bound of inflation with a tilt

We provide strong evidence for universality of the inflationary field range: given an accurate measurement of $({n}_{s},r)$, one can infer $\mathrm{\ensuremath{\Delta}}\ensuremath{\phi}$ in a model-independent way in the sub-Planckian regime for a range of universality classes of inflationary models. Both the tensor-to-scalar ratio as well as the spectral tilt are essential for the field range. Given the Planck constraints on ${n}_{s}$, the Lyth bound is strengthened by two orders of magnitude: whereas the original bound gives a sub-Planckian field range for $r\ensuremath{\lesssim}2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, we find that ${n}_{s}=0.96$ brings this down to $r\ensuremath{\lesssim}2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$.

The Voice Quality Characteristics of the Profound Hearing-Impaired Children with Reference to H1-H2 and Spectral tilt

The Voice Quality Characteristics of the Profound Hearing-Impaired Children with Reference to H1-H2 and Spectral tilt

The interaction of lexical and phrasal prosody in whispered speech.

The production and perception of Dutch whispered boundary tones, i.e., phrasal prosody, was investigated as a function of characteristics of the tone-bearing word, i.e., lexical prosody. More specifically, the disyllabic tone-bearing word also carried a pitch accent, either on the same syllable as the boundary tone (clash condition), or on the directly adjacent syllable (no clash condition). In a statement/question classification task listeners showed moderate, but above-chance performance for both conditions in whisper, which, however, was much worse as well as slower than in normal speech. The syllabic rhymes of speakers' productions were investigated for acoustic correlates of boundary tones. Results showed mainly secondary cues to intonation, that is, cues that are present in whisper as in normal speech, but minimal compensatory cues, which would reflect speakers' efforts to enhance their whispered speech signal in some way. This suggests that multiple prosodic events in close proximity are challenging to perceive and produce in whispered speech. A moderate increase in classification performance was found when that acoustic cue was enhanced that whispering speakers seemed to employ in a compensatory way: changing the spectral tilt of the utterance-final syllable improved perception of especially the poorer speakers and of intonation on stressed syllables.

A perceptually-motivated low-complexity instantaneous linear channel normalization technique applied to speaker verification

This paper proposes a new set of speech features called Locally-Normalized Cepstral Coefficients (LNCC) that are based on Seneff's Generalized Synchrony Detector (GSD). First, an analysis of the GSD frequency response is provided to show that it generates spurious peaks at harmonics of the detected frequency. Then, the GSD frequency response is modeled as a quotient of two filters centered at the detected frequency. The numerator is a triangular band pass filter centered around a particular frequency similar to the ordinary Mel filters. The denominator term is a filter that responds maximally to frequency components on either side of the numerator filter. As a result, a local normalization is performed without the spurious peaks of the original GSD. Speaker verification results demonstrate that the proposed LNCC features are of low computational complexity and far more effectively compensate for spectral tilt than ordinary MFCC coefficients. LNCC features do not require the computation and storage of a moving average of the feature values, and they provide relative reductions in Equal Error Rate (EER) as high as 47.7%, 34.0% or 25.8% when compared with MFCC, MFCC+CMN, or MFCC+RASTA in one case of variable spectral tilt, respectively.

ON THE MULTI-THREADED NATURE OF SOLAR SPICULES

A dominant constituent in the dynamic chromosphere are spicules. Spicules at the limb appear as relatively small and dynamic jets that are observed to everywhere stick out. Many papers emphasize the important role spicules might play in the energy and mass balance of the chromosphere and corona. However, many aspects of spicules remain a mystery. In this Letter we shed more light on the multi-threaded nature of spicules and their torsional component. We use high spatial, spectral and temporal resolution observations from the Swedish 1-m Solar Telescope in the H{\alpha} spectral line. The data targets the limb and we extract spectra from spicules far out from the limb to reduce the line-of-sight superposition effect. We discover that many spicules display very asymmetric spectra with some even showing multiple peaks. To quantify this asymmetry we use a double Gaussian fitting procedure and find an average velocity difference between the single Gaussian components to be between 20-30 km s$^{-1}$ for a sample of 57 spicules. We observe that spicules show significant sub-structure where one spicule consists of many 'threads'. We interpret the asymmetric spectra as line-of-sight superposition of threads in one spicule and therefore have a measure for a perpendicular flow inside spicules which will be important for future numerical model to reproduce. In addition we show examples of {\lambda}-x-slices perpendicular across spicules and find spectral tilts in individual threads providing further evidence for the complex dynamical nature of spicules.

Adaptive compensation for reliable spectral characteristics of a listening context in vowel perception

When precursor sounds are filtered to emphasize frequencies matching F2 of a subsequent target vowel, vowel perception decreases reliance on F2 (predictable cue) and increases reliance on spectral tilt (unpredictable cue) and vice versa. Previously, initial cue weights and weight changes (i.e., perceptual calibration to reliable signal properties) were larger for F2 than tilt, obscuring whether the magnitude of calibration reflects cue predictability or F2’s status as a primary cue to vowel identity. Here, vowels varied from /u/ to /i/ in tilt (-12-0 dB/octave) and the full range of F2 values (1000–2200 Hz) or a reduced range (1300–1900 Hz) designed to decrease F2 cue weights, making tilt the primary cue for vowel identification. Vowels were presented in isolation, then following sentences filtered to match the target vowel’s F2 or tilt. In isolation, cue weights for F2 were higher when identifying full-F2-range vowels and higher for tilt when identifying reduced-F2-range vowels. Weight changes (calibrati...

Cosmological observables in multi-field inflation with a non-flat field space

Using δN formalism, in the context of a generic multi-field inflation driven on a non-flat field space background, we revisit the analytic expressions of the various cosmological observables such as scalar/tensor power spectra, scalar/tensor spectral tilts, non-Gaussianity parameters, tensor-to-scalar ratio, and the various runnings of these observables. In our backward formalism approach, the subsequent expressions of observables automatically include the terms beyond the leading order slow-roll expansion correcting many of the expression at subleading order. To connect our analysis properly with the earlier results, we rederive the (well) known (single field) expressions in the limiting cases of our generic formulae. Further, in the light of PLANCK results, we examine for the compatibility of the consistency relations within the slow-roll regime of a two-field roulette poly-instanton inflation realized in the context of large volume scenarios.

Conversion from mutual helicity to self-helicity observed with IRIS

Context. In the upper atmosphere of the Sun observations show convincing evidence for crossing and twisted structures, which are interpreted as mutual helicity and self-helicity. Aims. We use observations with the new Interface Region Imaging Spectrograph (IRIS) to show the conversion of mutual helicity into self-helicity in coronal structures on the Sun. Methods. Using far UV spectra and slit-jaw images from IRIS and coronal images and magnetograms from SDO, we investigated the evolution of two crossing loops in an active region, in particular, the properties of the Si IV line profile in cool loops. Results. In the early stage two cool loops cross each other and accordingly have mutual helicity. The Doppler shifts in the loops indicate that they wind around each other. As a consequence, near the crossing point of the loops (interchange) reconnection sets in, which heats the plasma. This is consistent with the observed increase of the line width and of the appearance of the loops at higher temperatures. After this interaction, the two new loops run in parallel, and in one of them shows a clear spectral tilt of the Si IV line profile. This is indicative of a helical (twisting) motion, which is the same as to say that the loop has self-helicity. Conclusions. The high spatial and spectral resolution of IRIS allowed us to see the conversion of mutual helicity to self-helicity in the (interchange) reconnection of two loops. This is observational evidence for earlier theoretical speculations.

Long-time average spectrum in individuals with Parkinson disease.

Various methods of acoustic analysis have been used to describe phonatory deficits in Parkinson disease (PD), including long-time average spectrum (LTAS) analysis. The aim of this study was to utilize the LTAS to investigate laryngeal deficits in individuals with PD. Twenty-eight individuals with idiopathic PD and 10 controls were participants for this study. An LTAS was generated from a standard reading sample and analyzed using the following measurements: Mean spectral energy (MSE), first spectral peak, spectral tilt (ST), three spectral slope (SS) measures (i.e., SSF0-1kHz, SS1-5kHz, and SS ratio) and four spectral moments (mean, standard deviation, skewness, and kurtosis). Individuals with PD were found to demonstrate significantly lower MSE, spectral mean and spectral SD, along with higher spectral skewness compared to control speakers. Furthermore, ST was positively correlated with self-rated symptom severity and self-rated medication effectiveness for individuals with PD. The LTAS findings were consistent with either reduced vocal fold adduction or vocal fold bowing in individuals with PD compared to control speakers. Additionally, vocal fold adductory changes were one possible explanation for correlations between LTAS and self-ratings of medication effectiveness and disease severity.

Higgs-Dilaton cosmology: Universality versus criticality

The Higgs-Dilaton model is able to produce an early inflationary expansion followed by a dark energy dominated era responsible for the late time acceleration of the Universe. At tree level, the model predicts a small tensor-to-scalar ratio ($0.0021\leq r \leq 0.0034$), a tiny negative running of the spectral tilt ($-0.00057 \leq dn_s/d\ln k \leq -0.00034$) and a nontrivial consistency relation between the spectral tilt of scalar perturbations and the dark energy equation of state, which turns out to be close to a cosmological constant ($0 \leq 1+w_{DE} \leq 0.014$). We reconsider the validity of these predictions in the vicinity of the critical value of the Higgs self-coupling giving rise to an inflection point in the inflationary potential. The value of the inflationary observables in this case strongly depends on the parameters of the model. The tensor-to-scalar ratio can be large [$r\sim {\cal O}(0.1)$] and notably exceed its tree-level value. If that happens, the running of the scalar tilt becomes positive and rather big [$dn_s/d\ln k \sim {\cal O}(0.01)$] and the equation-of-state parameter of dark energy can significantly differ from a cosmological constant [$1+w_{DE}\sim {\cal O}(0.1)$].

On the rhythm of infant- versus adult-directed speech in Australian English.

The findings are reported of an investigation into rhythmic differences between infant-directed speech (IDS) and adult-directed speech (ADS) in a corpus of utterances from Australian English mothers speaking to their infants and to another adult. Given the importance of rhythmic cues to stress and word-segmentation in English, the investigation focused on the extent to which IDS makes such cues salient. Two methods of analysis were used: one focused on segmental durational properties, using a variety of durational measures; the other focused on the prominence of vocalic/sonorant segments, as determined by their duration, intensity, pitch, and spectral balance, using individual measures as well as composite measures of prominence derived from auditory-model analyses. There were few IDS/ADS differences/trends on the individual measures, though mean pitch and pitch variability were higher in IDS than ADS, while IDS vowels showed more negative spectral tilt. However, the model-based analyses suggested that differences in the prominence of vowels/sonorant segments were reduced in IDS, with further analysis suggesting that pitch contributed little to prominence. The reduction in prominence contrasts may be due to the importance of mood-regulation in speech to young infants, and may suggest that infants rely on segmental cues to stress and word-segmentation.

Quantitative measurement of vocal fold vibration in male radio performers and healthy controls using high-speed videoendoscopy.

PurposeAcoustic and perceptual studies show a number of differences between the voices of radio performers and controls. Despite this, the vocal fold kinematics underlying these differences are largely unknown. Using high-speed videoendoscopy, this study sought to determine whether the vocal vibration features of radio performers differed from those of non-performing controls.MethodUsing high-speed videoendoscopy, recordings of a mid-phonatory/i/ in 16 male radio performers (aged 25–52 years) and 16 age-matched controls (aged 25–52 years) were collected. Videos were extracted and analysed semi-automatically using High-Speed Video Program, obtaining measures of fundamental frequency (f0), open quotient and speed quotient. Post-hoc analyses of sound pressure level (SPL) were also performed (n = 19). Pearson's correlations were calculated between SPL and both speed and open quotients.ResultsMale radio performers had a significantly higher speed quotient than their matched controls (t = 3.308, p = 0.005). No significant differences were found for f0 or open quotient. No significant correlation was found between either open or speed quotient with SPL.DiscussionA higher speed quotient in male radio performers suggests that their vocal fold vibration was characterised by a higher ratio of glottal opening to closing times than controls. This result may explain findings of better voice quality, higher equivalent sound level and greater spectral tilt seen in previous research. Open quotient was not significantly different between groups, indicating that the durations of complete vocal fold closure were not different between the radio performers and controls. Further validation of these results is required to determine the aetiology of the higher speed quotient result and its implications for voice training and clinical management in performers.

A falsely fat curvaton with an observable running of the spectral tilt

In slow roll inflation, the running of the spectral tilt is generically proportional to the square of the deviation from scale invariance, αs∝(ns−1)2, and is therefore currently undetectable. We present a mechanism able to generate a much larger running within slow roll. The mechanism is based on a curvaton field with a large mass term, and a time evolving normalization. This may happen for instance to the angular direction of a complex field in presence of an evolving radial direction. At the price of a single tuning between the mass term and the rate of change of the normalization, the curvaton can be made effectively light at the CMB scales, giving a spectral tilt in agreement with observations. The lightness is not preserved at later times, resulting in a detectable running of the spectral tilt. This mechanism shows that fields with a large mass term do not necessarily decouple from the inflationary physics, and provides a new tool for model building in inflation.

Large-Nrunning of the spectral index of inflation

We extend previous classifications of inflationary models by means of their behaviour at large-N, where N is the number of e-foldings. In addition to the perturbative 1/N case, whose slow-roll parameters fall off as powers of 1/N, we introduce the constant, non-perturbative and logarithmic classes. This covers the large majority of inflationary models. Furthermore, we calculate the running of the spectral tilt for all these classes. Remarkably, we find that the tilt's runnings essentially cluster around the permil level. We comment on the implications for future experiments.