A critical analysis of loudness calculation methods

The physical meaning and methods of determining loudness were reviewed Loudness is a psychoacoustic metric which closely corresponds to the perceived intensity of a sound stimulus. It can be determined by graphical procedures, numerical methods, or by commercial software. These methods typically require the consideration of the 1/3 octave band spectrum of the sound of interest. The sounds considered in this paper are a 1 kHz tone and pink noise. The loudness of these sounds was calculated in eight ways using different combinations of input data and calculation methods. All the methods considered are based on Zwicker loudness. It was determined that, of the combinations considered, only the commercial software dBSonic and the loudness calculation procedure detailed in DIN 45631 using 1/3 octave band levels filtered using ANSI S1.11-1986 gave the correct values of loudness for a 1 kHz tone. Comparing the results between the sources also demonstrated the difference between sound pressure level and loudness. It was apparent that the calculation and filtering methods must be considered together, as a given calculation will produce different results for different 1/3 octave band input. In the literature reviewed, no reference provided a guide to the selection of the type of filtering that should be used in conjunction with the loudness computation method.

A critical analysis of loudness calculation methods

The physical meaning and calculation procedures for determining loudness was critically analyzed. Four noise sources were used in comparing the software packages dBFA dBSonic, which were used in the investigation to a public domain code. The purpose of the comparison was to evaluate the validity of the results obtained and to gain an idea of the shortcomings of the relevant standards. A comparison of the results for loudness was computed from various methods, used in the study. Two basic sources of input data such as a sound level meter (SLM) and a 01 dB data acquisition system (DAQ), were available for the comparison. The SLM directly gave 1/3 octave band levels, while the data from the DAQ was filtered to give the results. Five processing methods, including a Visual Basic (VB) program and a VB program adapted from dBFA, were used for the study. It was found that the calculation of loudness from 1/3 octave cannot be separated from the filtering process.

Evoked-potential audiogram of the Yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis (L)

Evoked-potential audiograms were obtained in two (one male and one female) Yangtze finless porpoises, Neophocaena phocaenoides asiaseorientalis. Sinusoidal amplitude-modulated 20-ms tone bursts were used as probes with recording envelope-following evoked potentials. A frequency range of 8 to 152 kHz was investigated. The range of greatest sensitivity covered frequencies from 45 to 139 kHz, and the lowest thresholds of 47.2 and 48.5 dB re: 1 μ Pa were found at a frequency of 54 kHz in the two subjects, respectively. At lower frequencies, threshold increased with a rate of around 14 dB/octave, and threshold steeply increased at 152 kHz. © 2005 Acoustical Society of America.

A Neural Network for Synthesizing the Pitch of an Acoustic Source

This article describes a neural network model capable of generating a spatial representation of the pitch of an acoustic source. Pitch is one of several auditory percepts used by humans to separate multiple sound sources in the environment from each other. The model provides a neural instantiation of a type of "harmonic sieve". It is capable of quantitatively simulating a large body of psychoacoustical data, including new data on octave shift perception.

A Spectral Network Model of Pitch Perception

A model of pitch perception, called the Spatial Pitch Network or SPINET model, is developed and analyzed. The model neurally instantiates ideas front the spectral pitch modeling literature and joins them to basic neural network signal processing designs to simulate a broader range of perceptual pitch data than previous spectral models. The components of the model arc interpreted as peripheral mechanical and neural processing stages, which arc capable of being incorporated into a larger network architecture for separating multiple sound sources in the environment. The core of the new model transforms a spectral representation of an acoustic source into a spatial distribution of pitch strengths. The SPINET model uses a weighted "harmonic sieve" whereby the strength of activation of a given pitch depends upon a weighted sum of narrow regions around the harmonics of the nominal pitch value, and higher harmonics contribute less to a pitch than lower ones. Suitably chosen harmonic weighting functions enable computer simulations of pitch perception data involving mistuned components, shifted harmonics, and various types of continuous spectra including rippled noise. It is shown how the weighting functions produce the dominance region, how they lead to octave shifts of pitch in response to ambiguous stimuli, and how they lead to a pitch region in response to the octave-spaced Shepard tone complexes and Deutsch tritones without the use of attentional mechanisms to limit pitch choices. An on-center off-surround network in the model helps to produce noise suppression, partial masking and edge pitch. Finally, it is shown how peripheral filtering and short term energy measurements produce a model pitch estimate that is sensitive to certain component phase relationships.

Supercontinuum Generation by Stimulated Raman Scattering and Parametric Four-Wave Mixing in Photonic Crystal Fibers

Supercontinuum generation is investigated experimentally and numerically in a highly nonlinear indexguiding photonic crystal optical fiber in a regime in which self-phase modulation of the pump wave makes a negligible contribution to spectral broadening. An ultrabroadband octave-spanning white-light continuum is generated with 60-ps pump pulses of subkilowatt peak power. The primary mechanism of spectral broadening is identified as the combined action of stimulated Raman scattering and parametric four-wave mixing. The observation of a strong anti-Stokes Raman component reveals the importance of the coupling between stimulated Raman scattering and parametric four-wave mixing in highly nonlinear photonic crystal fibers and also indicates that non-phase-matched processes contribute to the continuum. Additionally, the pump input polarization affects the generated continuum through the influence of polarization modulational instability. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate the importance of index-guiding photonic crystal fibers for the design of picosecond and nanosecond supercontinuum light sources. © 2002 Optical Society of America.

Fundamental limits to few-cycle pulse generation from compression of broadband supercontinua generated in photonic crystal fiber

The compression properties of octave-spanning supercontinuum spectra generated in photonic crystal fibers are studied using stochastic nonlinear Schrödinger equation simulations. The conditions under which sub-5 fs pulses can be obtained after compression are identified. © 2004 Optical Society of America.

A review of ADP processing software

Data processing is an essential part of Acoustic Doppler Profiler (ADP) surveys, which have become the standard tool in assessing flow characteristics at tidal power development sites. In most cases, further processing beyond the capabilities of the manufacturer provided software tools is required. These additional tasks are often implemented by every user in mathematical toolboxes like MATLAB, Octave or Python. This requires the transfer of the data from one system to another and thus increases the possibility of errors. The application of dedicated tools for visualisation of flow or geographic data is also often beneficial and a wide range of tools are freely available, though again problems arise from the necessity of transferring the data. Furthermore, almost exclusively PCs are supported directly by the ADP manufacturers, whereas small computing solutions like tablet computers, often running Android or Linux operating systems, seem better suited for online monitoring or data acquisition in field conditions. While many manufacturers offer support for developers, any solution is limited to a single device of a single manufacturer. A common data format for all ADP data would allow development of applications and quicker distribution of new post processing methodologies across the industry.

Notes pour la bibliographie du XIXe siècle. Quelques uns des livres contemporains... tirés de la bibliothèque d'un écrivain et bibliophile parisien dont le nom n'est pas un mystère [Oct. Uzanne]... [Vente les 2 et 3 mars 1894, hôtel des ventes, rue Drouot.]

[Vente (Livres). 1894-03-02 - 1894-03-03. Paris]

Horae ad usum romanum

F. 1-12v. Calendrier en français, à l’encre rouge et noire, où l’on remarque des formes dialectales picardes et plusieurs saints du Nord : « sainte Audegonde » (30 janvier) ; « le Candelier » (2 févr.) ; « ste Gertrude » (17 mars) ; « saint Quentin » (2 mai) ; « saint Ernoulx » [ep. Suessonensis] (16 août) ; « saint Bertin » (5 septembre) ; « saint Lambert » (17 septembre) ; « saint Franchois » (4 oct.) ; « saint Gillain » [mart. in Hannonia] (16 oct., Ghislain); « le jour st Estievene » (26 déc., rouge). Une deuxième main très cursive ajouté d’autres saints, dont « s. Amand » (6 févr.) ; « s. Waleri » (1er avril) ; « s. Fuscien » [mart. Ambianensis] (27 juin et 10 déc.) ; « s. Firmin » [mart. Ambianensis] (25 septembre) ; « s. Bavon » (1er oct.). F. 13v-17v. « ... hore sancte Crucis». F. 18v-22v. « ... hore de sancto Spiritu ».F. 23v-85. « ... hore beate marie virginis secundum usum romanum ». F. 86v-94v. Office de la Vierge, selon les temps de l’année. « ... officum beate Marie virginis quod dicitur per totum adventum ad vesperas ».F.95-115. « ... septem psalmi penitentiales cum suis litaniis et precibus ». A noter « ... sancte Lamberte... sancte Rumolde [ep. Mechlinensis]... sancte Fursee [ab. Latiniacensis] ... sancte Amande... sancte Vedaste, sancte Bavo... sancte Philiberte... santa Ursula... sancta Brigida... sancta Aldegondis, sancta Gertrudis... ».F.116v-152v. « ... vigilie mortuorum » office des morts à l’usage de Sarum-Normandie-Metz ; cf. K. Ottosen, Responsories..., p. 242 (116v-151). — « Octo versus beati Bernardi ». « Illumina oculos meos ne umquam obdormiam... » ; cf. Leroquais, Livres d’heures, I, XXX-XXXI (151-152v).F.153-158v. « Initium sancti evvangelii secundum Johannem... secundum Lucam... secundum Matheum... secundum Marcum ».F. 158v-166. Suffrages aux saints : « Memoria de santo Johanne Baptista... ; devota oratio... » ; — « ... de sancto Adriano » ; — « ... de sancto Sebastiano » ; — « ... de sancto Anthonio » ; — « ... de sancto Quintino » ; — « ... de sancto Nicholae » ; — « ... de sancto Andrea » ; — « ... de sancto Fiacro ».F.166v-174v. Prières à la Vierge. « ... devotissima oratio ad beatem virginem Mariam ». « O intemerata... O Johannes... » (éd. Wilmart, Auteurs spirituels, 488-490) (166v-169v). — « Alia oratio ad beatam virginem Mariam ». « Obsecro te.... » (éd. Leroquais, Livres d’heures, II, 346-347) (169v-174). Les deux prières sont rédigées à la forme masculine. — « Laus Marie virginis ». « Salve regina... » (Analecta Hymnica, L, 318-319, n° 245) (174-174v). F. 175-184v. Suffrages aux saintes : « ... de santa Barbara » ; — « ... de sancta Margareta » ; — « ... de sancta Katerina » ; — « ... de sancta Maria Magdelena » ; — « ... de sancta Appolonia » ; — « ... de sancta Venicie [Venice, forme dérivée de Véronique] » « Veni sponsa Christi... Versus. Diffusa est gratia... Oratio. Exaudi nos Deus ut sicut de beate Venicie festivitate gaudemus, ita pie devotionis erudiamur. Per.... » ; sur le culte de sainte Véronique/Venice, en particulier à Paris, voir Gr. A. RUNNALS, Le mystère de sainte Venice, Exeter, 1980 (Textes littéraires) (175-180v). — Prières diverses : « ... quinque gaudia de beata virgine Maria » « Gaude Virgo mater Christi... » (éd. Leroquais, Livres d’heures, I, XXVI-XXVII) (180v-182). — « Oratio devota ad Jesum Christum ». « Ave domine Jhesu Christe verbum patris » (éd. Wilmart, Auteurs spirituels, 412 [III]) (182-183). — « Oratio devota que dicitur ad elevationem Domini ». « Ave verum corpus Domini nostri... » (éd. Szövérffy, Die Annalen , II, 298-299) (183-184). — « Memore de saint Miquiel », en latin (184-184v).

Éducation des filles / de Fénelon ; précédée d'une introduction par Oct. Gréard,...

Collection : Bibliothèque des dames ; 11

Evangeliarium.

F. 1-33v. Temporal, du mercredi saint au 4e dimanche de l'Avent (incompl. du début) : — Exultet (chant simple) (6v). F. 33v. Sanctoral. F. 49. Table des évangiles, adaptée plus tard à l'usage d'une abbaye cistercienne. F. 51. Commun des saints. F. 59. Dédicace. F. 60. Messes votives et diverses. F. 62v-64. Additions : 4e dim. après l'octave de l'Épiphanie (62v) ; — Évangile de la Visitation (63) ; — Fragments notés (62v-64).