The effect of inharmonic partials on pitch of piano tones

Piano tones have partials whose frequencies are sharp relative to harmonic values. A listening test was conducted to determine the effect of inharmonicity on pitch for piano tones in the lowest three octaves of a piano. Nine real tones from the lowest three octaves of a piano were analyzed to obtain frequencies, relative amplitudes, and decay rates of their partials. Synthetic inharmonic tones were produced from these results. Synthetic harmonic tones, each with a twelfth of a semitone increase in the fundamental, were also produced. A jury of 21 listeners matched the pitch of each synthetic inharmonic tone to one of the synthetic harmonic tones. The effect of the inharmonicity on pitch was determined from an average of the listeners' results. For the nine synthetic piano tones studied, pitch increase ranged from approximately two and a half semitones at low fundamental frequencies to an eighth of a semitone at higher fundamental frequencies.     

Reliability in Perceptual Analysis of Voice Quality

This study focuses on speaking voice quality in male teachers (n = 35) and male actors (n = 36), who represent untrained and trained voice users, because we wanted to investigate normal and supranormal voices. In this study, both substantial and methodologic aspects were considered. It includes a method for perceptual voice evaluation, and a basic issue was rater reliability. A listening group of 10 listeners, 7 experienced speech-language therapists, and 3 speech-language therapist students evaluated the voices by 15 vocal characteristics using VA scales. Two sets of voice signals were investigated: text reading (2 loudness levels) and sustained vowel (3 levels). The results indicated a high interrater reliability for most perceptual characteristics. Connected speech was evaluated more reliably, especially at the normal level, but both types of voice signals were evaluated reliably, although the reliability for connected speech was somewhat higher than for vowels. Experienced listeners tended to be more consistent in their ratings than did the student raters. Some vocal characteristics achieved acceptable reliability even with a smaller panel of listeners. The perceptual characteristics grouped in 4 factors reflected perceptual dimensions.     

Dependence of jaw opening on pitch and vowel in singers

In singing, F₀ sometimes is much higher than the typical frequency value of F₁. According to previous investigations, sopranos raise F₁ to a frequency near F₀ by widening the jaw opening in such cases. In the present study, the jaw opening was measured in 10 professional singers of different categorizations whose task was to sing an ascending two-octave scale on different vowels. Their normal F₁ values for these vowels were determined at a low F₀. Only for the vowels /a/ and /a/ did the singers widen the jaw opening when F₀ approached the F₁ value measured at a low pitch. For the other vowels, jaw opening was widened, beginning at a higher F₀. It is assumed that for these vowels the singers used other articulatory means to increase F₁.     

Accuracy of pitch matching for pure tones and for complex tones with overlapping or nonoverlapping harmonics.

The discrimination of the fundamental frequency (fo) of pairs of complex tones with no common harmonics is worse than the discrimination of fo for tones with all harmonics in common. These experiments were conducted to assess whether this effect is a result of pitch shifts between pairs of tones without common harmonics or whether it reflects influences of spectral differences (timbre) on the accuracy of pitch perception. In experiment 1, pitch matches were obtained between sounds drawn from the following types: (1) pure tones (P) with frequencies 100, 200, or 400 Hz; (2) a multiple-component complex tone, designated A, with harmonics 3, 4, 8, 9, 10, 14, 15, and fo = 100, 200, or 400 Hz; (3) A multiple-component complex tone, designated B, with harmonics 5, 6, 7, 11, 12, 13, 16, and with fo = 100, 200 or 400 Hz. The following matches were made; A vs A, B vs B, A vs P, B vs P and P vs P. Pitch shifts were found between the pure tones and the complex tones (A vs P and B vs P), but not between the A and B tones (A vs B). However, the variability of the A vs B matches was significantly greater than that of the A vs A or B vs B matches. Also, the variability of the A vs P and B vs P matches was greater than that for the A vs B matches. In a second experiment, frequency difference limens (DLCs) were measured for the A vs A, B vs B, and A vs B pairs of sounds. The DLCs were larger for the A vs B pair than for A vs A or B vs B. The results suggest that the poor frequency discrimination of tones with no common harmonics does not result from pitch shifts between the tones. Rather, it seems that spectral differences between tones interfere with judgements of their relative pitch.     

Frequency discrimination of complex tones with overlapping and non-overlapping harmonics

These experiments address the following issues. (1) When two complex tones contain different harmonics, do the differences in timbre between them impair the ability to discriminate the pitches of the tones? (2) When two complex tones have only a single component in common, and that component is the most discriminable component in each tone, is the frequency discrimination of the component affected by differences in residue pitch between the two tones? (3) How good is the pitch discrimination of complex tones with no common components when each tone contains multiple harmonics, so as to avoid ambiguity of pitch? (4) Is the pitch discrimination of complex tones with common harmonics impaired by shifting the component frequencies to nonharmonic values? In all experiments, frequency difference limens (DLCs) were measured for multiple-component complex tones, using an adaptive two-interval, two-alternative, forced-choice task. Three highly trained subjects were used. The main conclusions are as follows. (1) When two tones have the first six harmonics in common, DLCs are larger when the upper harmonics are different than when the upper harmonics are in common or are absent. It appears that differences in timbre impair DLCs. (2) Discrimination of the frequency of a single common partial in two complex tones is worse when the two tones have different residue pitches than when they have the same residue pitch. (3) DLCs for complex tones with no common harmonics are generally larger than those for complex tones with common harmonics. For the former, large individual differences occur, probably because subjects are affected differently by differences in timbre. (4) DLCs for harmonic complex tones are smaller than DLCs for complex tones in which the components are mistuned from harmonic values. This can probably be attributed to the less distinct residue pitch of the inharmonic complexes, rather than to reduced discriminability of partials. Overall, the results support the idea that DLCs for complex tones with common harmonics depend on residue pitch comparisons, rather than on comparisons of the pitches of partials.     

Voice-over: Perceptual and Acoustic Analysis of Vocal Features

Voice-overs are professional voice users who use their voices to market products in the electronic media. The purposes of this study were to (1) analyze voice-overed and non-overed productions of an advertising text in two groups consisting of 10 male professional voice-overs and 10 male non-voice-overs; and (2) determine specific acoustic features of voice-over productions in both groups. A na?ve group of listeners were engaged for the perceptual analysis of the recorded advertising text. The voice-overed production samples from both groups were submitted for analysis of acoustic and temporal features. The following parameters were analyzed: (1) the total text length, (2) the length of the three emphatic pauses, (3) values of the mean, (4) minimum, (5) maximum fundamental frequency, and (6) the semitone range. The majority of voice-overs and non-voice-overs were correctly identified by the listeners in both productions. However voice-overs were more consistently correctly identified than non-voice-overs. The total text length was greater for voice-overs. The pause time distribution was statistically more homogeneous for the voice-overs. The acoustic analysis indicated that the voice-overs had lower values of mean, minimum, and maximum fundamental frequency and a greater range of semitones. The voice-overs carry the voice-overed production features to their non-voice-overed production.     

Detection and F0 discrimination of harmonic complex tones in the presence of competing tones or noise

Normal-hearing listeners' ability to "hear out" the pitch of a target harmonic complex tone (HCT) was tested with simultaneous HCT or noise maskers, all bandpass-filtered into the same spectral region (1200-3600 Hz). Target-to-masker ratios (TMRs) necessary to discriminate fixed fundamental-frequency (F0) differences were measured for target F0s between 100 and 400 Hz. At high F0s (400 Hz), asynchronous gating of masker and signal, presenting the masker in a different F0 range, and reducing the F0 rove of the masker, all resulted in improved performance. At the low F0s (100 Hz), none of these manipulations improved performance significantly. The findings are generally consistent with the idea that the ability to segregate sounds based on cues such as F0 differences and onset/offset asynchronies can be strongly limited by peripheral harmonic resolvability. However, some cases were observed where perceptual segregation appeared possible, even when no peripherally resolved harmonics were present in the mixture of target and masker. A final experiment, comparing TMRs necessary for detection and F0 discrimination, showed that F0 discrimination of the target was possible with noise maskers at only a few decibels above detection threshold, whereas similar performance with HCT maskers was only possible 15-25 dB above detection threshold.     

Effects of roving level and spectral range on vowel formant discrimination

Thresholds of vowel formant discrimination for F1 and F2 of isolated vowels with full and partial vowel spectra were measured for normal-hearing listeners at fixed and roving speech levels. Performance of formant discrimination was significantly better for fixed levels than for roving levels with both full and partial spectra. The effect of vowel spectral range was present only for roving levels, but not for fixed levels. These results, consistent with studies of profile analysis, indicated different perceptual mechanisms for listeners to discriminate vowel formant frequency at fixed and roving levels.     

Low pitch LWIR QWIPs: Performance level and image quality

We present recent results obtained on 15 μm pitch LWIR QWIP arrays at Sofradir. Based on experimental data gathered on several QWIP wafers, the performance (NETD) at the system level has been estimated. We show that, in spite of the small pitch, values as low as 50 mK can be achieved for rather closed optical systems (f/2.5) and for operating temperatures (74 K) compatible with available compact cryo-coolers.We also demonstrate that specific pixel configurations can be designed to investigate the pixel-to-pixel optical crosstalk. Such measurements can help to better understand the limitations set by the geometry of the pixel on the Modulation Transfer Function (MTF). In particular, we show that the optical crosstalk due to photon transfer through the inter-pixel space is rather small for unthinned devices.     

Acoustic analysis of the speaking voice after thyroidectomy

Voices of 47 female patients were analyzed before and after thyroidectomy, with preservation of the recurrent and superior laryngeal nerves and normal vocal fold motility during the observation period. A mean decrease of the speaking fundamental frequency (SFF) of 12 Hz was found on day 4; in 8 patients the postoperative vocal pitch was more than 2 semitones lower. The distance between the highest and lowest F₀ during speaking was diminished (speech was more monotone) and the vocal jitter was elevated. In the frequency spectrum, there was a diminished prominence of the harmonics. The other spectral parameters (as the slope of the spectrum and the H1/H2 ratio) were unchanged. All changes had disappeared the fifteenth day, except for a lower SFF (>2 semitones) in 2 cases. It is concluded that after normal dissection of the laryngeal nerves, and in the absence of vocal fold paresis, other reasons for voice changes immediately after thyroidectomy remain: alterations in the neck muscles, in the laryngeal mucosa, and in the patient's general condition. Although the effects seem limited and of short duration, knowledge of them is helpful when informing the patient before thyroid surgery.     

Effects of frequency modulated tones and vowel formants on perioral muscle activity during isometric lip rounding

Two studies were conducted to assess the sensitivity of perioral muscles to vowel-like auditory stimuli. In one study, normal young adults produced an isometric lip rounding gesture while listening to a frequency modulated tone (FMT). The fundamental of the FMT was modulated over time in a sinusoidal fashion near the frequency ranges of the first and second formants of the vowels /u/ and /i/ (rate of modulation = 4.5 or 7 Hz). In another study, normal young adults produced an isometric lip rounding gesture while listening to synthesized vowels whose formant frequencies were modulated over time in a sinusoidal fashion to simulate repetitive changes from the vowel /u/ to /i/ (rate of modulation = 2 or 4 Hz). The FMTs and synthesized vowels were presented binaurally via headphones at 75 and 60 dB SL, respectively. Muscle activity from the orbicularis oris superior and inferior and from lip retractors was recorded with surface electromyography (EMG). Signal averaging and spectral analysis of the rectified and smoothed EMG failed to show perioral muscle responses to the auditory stimuli. Implications for auditory feedback theories of speech control are discussed.     

大口径激光玻璃环抛光学沥青抛光胶

研制了四种不同沥青和松香含量的光学沥青抛光胶,对其形貌、针入度、玻璃化转变温度、软化点和粘度等参量进行了表征。从组成和结构分析了抛光胶三种物理状态变化原因,将玻璃化转变温度和软化点作为其临界转变温度。实验研究了四种抛光胶对大口径激光玻璃的抛光效果,发现抛光胶中沥青和松香的质量分数分别为30%和70%时,抛光效果比较理想,在像散和表面疵病控制方面能够满足要求,可作为大口径激光玻璃抛光专用胶。     

The discrimination of baboon grunt calls and human vowel sounds by baboons

The ability of baboons to discriminate changes in the formant structures of a synthetic baboon grunt call and an acoustically similar human vowel (/epsilon/) was examined to determine how comparable baboons are to humans in discriminating small changes in vowel sounds, and whether or not any species-specific advantage in discriminability might exist when baboons discriminate their own vocalizations. Baboons were trained to press and hold down a lever to produce a pulsed train of a standard sound (e.g., /epsilon/ or a baboon grunt call), and to release the lever only when a variant of the sound occurred. Synthetic variants of each sound had the same first and third through fifth formants (F1 and F3-5), but varied in the location of the second formant (F2). Thresholds for F2 frequency changes were 55 and 67 Hz for the grunt and vowel stimuli, respectively, and were not statistically different from one another. Baboons discriminated changes in vowel formant structures comparable to those discriminated by humans. No distinct advantages in discrimination performances were observed when the baboons discriminated these synthetic grunt vocalizations.     

Behavior of laryngeal muscles of the late William Vennard

Behavior of the cricothyroid, lateral cricoarytenoid, vocalis, and interarytenoid muscles of William D. Vennard was electromyographically investigated. This article demonstrates electromyographic recordings that have not been published. Data presentation and discussion are focused on vocal registers, some phrases for voice training and warm-up, vowels, phonation modes, fundamental frequency control, the interarytenoid muscle, and some nonsinging behaviors     

The relation between the human frequency-following response and the low pitch of complex tones

The relation between the auditory brain stem potential called the frequency-following response (FFR) and the low pitch of complex tones was investigated. Eleven complex stimuli were synthesized such that frequency content varied but waveform envelope periodicity was constant. This was accomplished by repeatedly shifting the components of a harmonic complex tone upward in frequency by delta f of 20 Hz, producing a series of six-component inharmonic complex tones with constant intercomponent spacing of 200 Hz. Pitch-shift functions were derived from pitch matches for these stimuli to a comparison pure tone for each of four normal hearing adults with extensive musical training. The FFRs were recorded for the complex stimuli that were judged most divergent in pitch by each subject and for pure-tone signals that were judged equal in pitch to these complex stimuli. Spectral analyses suggested that the spectral content of the FFRs elicited by the complex stimuli did not vary consistently with component frequency or the first effect of pitch shift. Furthermore, complex and pure-tone signals judged equal in pitch did not elicit FFRs of similar spectral content.