Measurement-Based Automatic Parameterization of a Virtual Acoustic Room Model

Modernien auralisaatiotekniikoiden ansiosta kuulokkeilla voidaan tuottaa kuuntelukokemus, joka muistuttaa useimpien äänitteiden tuotannossa oletettua kaiutinkuuntelua. Huoneakustinen mallinnus on tärkeä osa toimivaa auralisaatiojärjestelmää. Huonemallinnuksen parametrien määrittäminen vaatii kuitenkin ammattitaitoa ja aikaa. Tässä työssä kehitetään järjestelmä parametrien automaattiseksi määrittämiseksi huoneakustisten mittausten perusteella. Parametrisaatio perustuu mikrofoniryhmällä mitattuihin huoneen impulssivasteisiin ja voidaan jakaa kahteen osaan: suoran äänen ja aikaisten heijastusten analyysiin sekä jälkikaiunnan analyysiin. Suorat äänet erotellaan impulssivasteista erilaisia signaalinkäsittelytekniikoita käyttäen ja niitä hyödynnetään heijastuksia etsivässä algoritmissa. Äänilähteet ja heijastuksia vastaavat kuvalähteet paikannetaan saapumisaikaeroon perustuvalla paikannusmenetelmällä ja taajuusriippuvat etenemistien vaikutukset arvioidaan kuvalähdemallissa käyttöä varten. Auralisaation jälkikaiunta on toteutettu takaisinkytkevällä viiveverkostomallilla. Sen parametrisointi vaatii taajuusriippuvan jälkikaiunta-ajan ja jälkikaiunnan taajuusvasteen määrittämistä. Normalisoitua kaikutiheyttä käytetään jälkikaiunnan alkamisajan löytämiseen mittauksista ja simuloidun jälkikaiunnan alkamisajan asettamiseen. Jälkikaiunta-aikojen määrittämisessä hyödynnetään energy decay relief -metodia. Kuuntelukokeiden perusteella automaattinen parametrisaatiojärjestelmä tuottaa parempia tuloksia kuin parametrien asettaminen manuaalisesti huoneen summittaisten geometriatietojen pohjalta. Järjestelmässä on ongelmia erityisesti jälkikaiunnan ekvalisoinnissa, mutta käytettyihin suhteellisen yksinkertaisiin tekniikoihin nähden järjestelmä toimii hyvin.Modern auralization techniques enable making the headphone listening experience similar to the experience of listening with loudspeakers, which is the reproduction method most content is made to be listened with. Room acoustic modeling is an essential part of a plausible auralization system. Specifying the parameters for room modeling requires expertise and time. In this thesis, a system is developed for automatic analysis of the parameters from room acoustic measurements. The parameterization is based on room impulse responses measured with a microphone array and can be divided into two parts: the analysis of the direct sound and early reflections, and the analysis of the late reverberation. The direct sounds are separated from the impulse responses using various signal processing techniques and used in the matching pursuit algorithm to find the reflections in the impulse responses. The sound sources and their reflection images are localized using time difference of arrival -based localization and frequency-dependent propagation path effects are estimated for use in an image source model. The late reverberation of the auralization is implemented using a feedback delay network. Its parameterization requires the analysis of the frequency-dependent reverberation time and frequency response of the late reverberation. Normalized echo density is used to determine the beginning of the late reverberation in the measurements and to set the starting point of the modeled late field. The reverberation times are analyzed using the energy decay relief. A formal listening test shows that the automatic parameterization system outperforms parameters set manually based on approximate geometrical data. Problems remain especially in the precision of the late reverberation equalization but the system works well considering the relative simplicity of the processing methods used

Appendix S1

Spreadsheet with local stratigraphic ranges of Late Ordovician-Early Silurian brachiopods

Brachiopod genus local ranges

csv file with the local stratigraphic ranges of brachiopod taxa (species where resolved, otherwise genera). Please contact authors with specific questions about the structure of the database and the meaning of column headings. R code for analysis of this dataset is included as Supplemental Material in the publication

Figure S3 from Identifying the most surprising victims of mass extinction events: an example using Late Ordovician Brachiopods

Crossplots of median predicted risk estimates from models based on the full dataset and from models based on the dataset with single-interval and single-region genera removed. Median predicted risk estimates are based on all background intervals for the full dataset but exclude interval S1 (due to edge effects, see figure S2 caption) for the culled dataset. Both sets of risk estimates are strongly correlated for both the latest Katian (Katian4) interval and the Hirnantian interval (Katian 4 R2 = 0.76, Hirnantian, R2 = 0.76)

Science paper, External Database 2

External Database 2. Data used for Phanerozoic drill-hole size and prey size analyses.<div><br></div><div>Associated with paper:</div><div>A.A. Klompmaker, M. Kowalewski, J.W. Huntley, S. Finnegan. 2017. Increase in predator-prey size ratios throughout the Phanerozoic history of marine ecosystems. Science.<br></div

Figure S5 from Identifying the most surprising victims of mass extinction events: an example using Late Ordovician Brachiopods

Same as Figure S1 but with single-interval and single-region genera removed from both the background and mass extinction intervals. Histograms showing frequency distributions of simulated Foliomena fauna genus extinctions for each background interval model. In each sampling iteration, 112 genera were randomly drawn using per-genus expected risk estimates from the associated background model as sampling probabilities. 10,000 iterations were performed for each model. Red arrows indicate the number of Foliomena fauna extinctions observed during the latest Katian

Science paper, External Database 1

External Database 1. Data used for drill-hole size and predator size analyses of primarily extant drilling taxa.<div><br></div><div>Associated with paper: </div><div>A.A. Klompmaker, M. Kowalewski, J.W. Huntley, S. Finnegan. 2017. Increase in predator-prey size ratios throughout the Phanerozoic history of marine ecosystems. Science.</div

Description of potential extinction risk predictors from Identifying the most surprising victims of mass extinction events: an example using Late Ordovician Brachiopods

Description of the various aspects of geographic, bathymetric, environmental, and stratigraphic distribution considered as potential predictors of apparent extinction risk

Figure S1 from Identifying the most surprising victims of mass extinction events: an example using Late Ordovician Brachiopods

Histograms showing frequency distributions of simulated Foliomena fauna genus extinctions for each background interval model. In each sampling iteration, 112 genera were randomly drawn using per-genus expected risk estimates from the associated background model as sampling probabilities. 10,000 iterations were performed for each model. Red arrows indicate the number of Foliomena fauna extinctions observed during the latest Katian

Supplementary Figures from Hierarchical complexity and the size limits of life

Supplementary Figures S1 - S