Guilherme Schmidt Câmara

• Lartillot, Olivier; Nymoen, Kristian; Câmara, Guilherme Schmidt & Danielsen, Anne (2021). Computational localization of attack regions through a direct observation of the audio waveform. Journal of the Acoustical Society of America. ISSN 0001-4966. 149(1), p. 723–736. doi: 10.1121/10.0003374.
• Senn, Olivier; Amadeus Bechtold, Toni; Rose, Dawn; Câmara, Guilherme Schmidt; Du Vel, Nina & Jerjen, Rafael [Show all 10 contributors for this article] (2020). Experience of Groove Questionnaire: Instrument Development and Initial Validation. Music Perception. ISSN 0730-7829. 38(1), p. 46–65. doi: 10.1525/MP.2020.38.1.46.
• Câmara, Guilherme Schmidt; Nymoen, Kristian; Lartillot, Olivier & Danielsen, Anne (2020). Timing Is Everything... Or Is It? Effects of Instructed Timing Style, Reference and Pattern on Drum Kit Sound in Groove-Based Performance. Music Perception. ISSN 0730-7829. 38(1), p. 1–26. doi: 10.1525/mp.2020.38.1.1. Full text in Research Archive
• Câmara, Guilherme Schmidt; Nymoen, Kristian; Lartillot, Olivier & Danielsen, Anne (2020). Effects of instructed timing on electric guitar and bass sound in groove performance. Journal of the Acoustical Society of America. ISSN 0001-4966. 147(2), p. 1028–1041. doi: 10.1121/10.0000724.
• Sioros, George; Câmara, Guilherme Schmidt & Danielsen, Anne (2019). Mapping Timing Strategies in Drum Performance. In Flexer, Arthur; Peeters, Geoffroy; Urbano, Julián & Volk, Anja (Ed.), Proceedings of the 20th International Society for Music Information Retrieval Conference, ISMIR 2019. International Society for Music Information Retrieval. ISSN 9781732729919.
• Danielsen, Anne; Nymoen, Kristian; Anderson, Evan; Câmara, Guilherme Schmidt; Langerød, Martin Torvik & Thompson, Marc R. [Show all 7 contributors for this article] (2019). Where is the beat in that note? Effects of attack, duration, and frequency on the perceived timing of musical and quasi-musical sounds. Journal of Experimental Psychology: Human Perception and Performance. ISSN 0096-1523. 45(3), p. 402–418. doi: 10.1037/xhp0000611. Show summary

  The perceptual center (P-center) of a sound is typically understood as the specific moment at which it is perceived to occur. Using matched sets of real and artificial musical sounds as stimuli, we probed the influence of attack (rise time), duration, and frequency (center frequency) on perceived P-center location and P-center variability. Two different methods to determine the P-centers were used: Clicks aligned in-phase with the target sounds via the method of adjustment, and tapping in synchrony with the target sounds. Attack and duration were the primary cues for P-center location and P-center variability; P-center variability was found to be a useful measure of P-center shape. Consistent interactions between attack and duration were also found. Probability density distributions for each stimulus display a systematic pattern of P-center shapes ranging from narrow peaks close to the onset of sounds with fast attack and short duration, to wider and flatter shapes indicating a range synchronization points for sounds with slow attack and long duration. The results support the conception of P-centers as not simple time points, but "beat bins" with characteristic shapes, and the shapes and locations of these beat bins are dependent upon both the stimulus and the synchronization task.

• Câmara, Guilherme Schmidt & Danielsen, Anne (2018). Groove. In Alexander, Rehding & Steven, Rings (Ed.), The Oxford Handbook of Critical Concepts in Music Theory. Oxford University Press. ISSN 9780190454746. doi: 10.1093/oxfordhb/9780190454746.013.17. Full text in Research Archive

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• Danielsen, Anne; Câmara, Guilherme Schmidt; Lartillot, Olivier; Leske, Sabine Liliana & Spiech, Connor (2022). Musical rhythm. Behavioural, computational and neurophysiological perspectives.
• Câmara, Guilherme Schmidt & Lokna, Maria (2021). Intervju i Morgenbladet - "Kan man forske på hva som er groovy?". [Newspaper]. Morgenbladet.
• Câmara, Guilherme Schmidt & Pileberg, Silje (2021). New research could inspire experimental musicians. Show summary

  https://www.uio.no/ritmo/aktuelt/aktuelle-saker/2021/forskning-tips-musikere.html

• Câmara, Guilherme Schmidt (2021). Presentation and Summary of Ph.D. Project: "Timing Is Everything . . . Or Is It? Investigating Timing and Sound Interactions in the Performance of Groove-Based Microrhythm".
• Câmara, Guilherme Schmidt (2021). Trial Lecture for Ph.D. disputation: "How far can we predict aesthetic effects from physical properties within and beyond groove music, and what can different microrhythmic feels communicate to listeners?".
• Ganis, Francesco; Dahl, Sofia; Câmara, Guilherme Schmidt & Danielsen, Anne (2021). Beat precision and perceived danceability in drum grooves. Show summary

  Musicians can place the time-position of events with high precision and according to personal preference, genre and tempo [1]. For instance, the swing ratio is not kept constant, but it is systematically adapted to a global tempo [2]. In contemporary music, drummers can achieve a specific feel by manipulating the timing of rhythms in different ways and placing event onsets earlier or later compared to the time reference [1]. These small adjustments in time are also referred to as micro-timing variations. The aim of this study was to investigate the influence of micro-timing variations in live-played rhythms on the perceived danceability and timing precision. The stimuli were chosen from Câmara et al. [1] where drummers were playing two different patterns with different timing styles (laid-back, pushed, on-beat). Two drummers’ performances were selected based on their reported average systematic timing. These 12 recordings were mixed with the instrumental backing track (bass and guitar) heard by the drummers to form the stimuli. Forty participants (M = 28.23 years, SD = 11.80), 28 males and 12 females, with varying musical background were recruited via social media (Facebook pages, groups and direct messages to chat groups). Participants were sent a link to the online listening test using Google Forms with modifications that presented the stimuli as embedded videos. Each video started with a prompt to wear headphones followed by 4 bars of groove for a total of 11 seconds (with a static image). For each page, the participant was presented with a reference track (on-beat timing) and a “beat” track (laid-back or pushed timing) and asked to rate the perceived danceability from 1 (not danceable at all) to 5 (very danceable). Additionally, listeners were asked to compare the beat with the reference track and indicate whether this was pushed (ahead), laid-back (behind) or on-beat (synced with) the reference in terms of timing. Preliminary results indicate that micro-timing variations affect the perceived danceability. On-beat patterns were rated with the highest danceability, followed by laid-back and pushed styles. The drummer that obtained the highest danceability rating for the laid-back performance is also the one that was mainly recognized as on-beat performer. As expected, identification of timing (ahead, behind or on) proved to be difficult. Using the instrumental backing track as a time reference could possibly have made the task even harder for untrained listeners. Future research could address this by comparing danceability ratings for the grooves mixed with different backing tracks. References [1] G. S. Câmara, K. Nymoen, O. Lartillot, and A. Danielsen, “Timing Is Everything…Or Is It? Effects of Instructed Timing Style, Reference, and Pattern on Drum Kit Sound in Groove-Based Performance,” Music Percept., vol. 38, no. 1, pp. 1–26, Sep. 2020, doi: 10.1525/mp.2020.38.1.1. [2] H. Honing and W. B. de Haas, “Swing Once More: Relating Timing and Tempo in Expert Jazz Drumming,” Music Percept., vol. 25, no. 5, pp. 471–476, Jun. 2008, doi: 10.1525/mp.2008.25.5.471.

• Câmara, Guilherme Schmidt; Sioros, George & Danielsen, Anne (2021). Mapping timing and intensity strategies in drum-kit performance via hierarchical clustering and phylogenetic visualizations . Show summary

  Background and Aim: Findings from performance timing experiments have shown that drummers are able to systematically play stroke onsets significantly earlier and later than an instructed on-the-beat performance (Câmara et al., 2020; Danielsen et al., 2015), and purportedly able to further control the degree of onset asynchrony between the various constituent instruments of the drum-kit (Câmara and Danielsen, 2019). Previous investigations have focused on comparing average statistical trends of onset timing between timing styles across entire groups of drummers. In this study, we map performance strategies present at the individual participant level and categorize the different archetypical ways in which drummers express different timing styles. We focus on the onset asynchrony and intensity of strokes between drum-kit instruments, and in relation to a metrical grid, and hypothesize that drummers employ consistent strategies to achieve different desired timing styles, choosing different instruments (snare/kick/hi-hat) in the rhythmic pattern to generate in-sync, late, and early timing performances. Methods: In a previous experiment (Câmara et al., 2020), twenty-two drummers were instructed to play a basic “back-beat” pattern along to a metronome and a pre-recorded instrumental track in three different timing conditions: laid-back, on-the-beat, and pushed. Here, we conduct a hierarchical cluster analysis of various onset and intensity features in this data set, combined with phylogenetic tree visualizations to provide an overview of the strategies used by the drummers to distinguish laid-back/pushed from on-the-beat performances. Furthermore, we encode the features of the onset or intensity clusters into microtiming archetypes that visually summarize the general characteristics of the drummers’ strategy in each cluster. Results: Overall, three overarching onset strategies were used to distinguish pushed/laid-back from on-the-beat performances: (1) strong “general earliness/lateness” strategies: most instruments are consistently played earlier/later in time relative to the grid; (2) subtler “early/late flam” strategies: most instruments are played synchronously with the grid but at least one instrument is played distinctively early/late ; and (3) even subtler “ambiguously early/late compound sound” strategies: two instruments are played synchronously in relation to each other as a compound sound, but one instrument is played synchronous with the grid and the other is played early/late. While no clear intensity manipulation patterns emerged to exclusively distinguish laid-back/pushed timing, they serve as a means of enhancing or diminishing the effect of intentionally produced asynchronies. Conclusion: Results indicate that performers utilize a range of inter-instrument onset timing and intensity relationships to express microrhythmic feel in groove performance, that is, different drummers use different means to achieve the same desired feel. Implications: The novel methods developed in this study may be applied to analysis of commercial recordings to provide insight into the idiomatic timing–sound strategies of influential performers and/or genres/styles more generally. References: Câmara, G. S., & Danielsen, A. (2019). Groove. In A. Rehding & S. Rings (Eds.), The Oxford handbook of critical concepts in music theory (pp. 271–294). Oxford University Press. Câmara, G. S., Nymoen, K., Lartillot, O., & Danielsen, A. (2020). Timing Is Everything . . . or Is It? Effects of Instructed Timing Style, Reference, and Pattern on Drum Kit Sound in Groove-Based Performance. Music Perception, 38(1), 1–26. Danielsen, A., Waadeland, C. H., Sundt, H. G., & Witek, M. A. G. (2015). Effects of instructed timing and tempo on snare drum sound in drum kit performance. Journal of the Acoustical Society of America, 138(4), 2301–2316.

• Câmara, Guilherme Schmidt (2020). Original concert performance with funk/soul ensemble "Baba Soul & The Professors of Funk", Jazz Fest Trondheim 2020.
• Lilleslåtten, Mari; Câmara, Guilherme Schmidt & Danielsen, Anne (2020). Hva du synes er bra musikk avgjøres på noen tusendels sekunder. [Internet]. Forskning.no.
• Sioros, George; Câmara, Guilherme Schmidt & Danielsen, Anne (2019). Mapping Timing Strategies in Drum Performance.
• Sioros, George; Câmara, Guilherme Schmidt; Danielsen, Anne & Nymoen, Kristian (2019). Timing and drummers’ movement: A novel methodology for performance analysis . Show summary

  Timing is an important aspect of groove music. The relationship between musicians’ body motion in performance and timing is, however, as yet not well understood Timing and drummers’ movement: A novel methodology for performance analysis . In the present study we recorded movement of 20 drummers performing the same rhythmic pattern under four different timing instructions: natural, on- the-beat, laid-back and pushed. Motion capture data synchronized to audio recordings of their performances were collected as part of a larger experimental project. This presentation focuses on our method for analyzing motion capture data. The aim of the analysis is a) to identify common movement strategies for sub-groups of drummers, and b) to identify strategies for achieving the four different timing conditions across drummers. In this presentation we focus on the movement of the left arm, and particularly on the preparation and rebound phase of the snare strokes. To explore and analyze the data without statistically testing a priori hypotheses about specific performance techniques, we combined existing practices from different disciplines into a novel methodology. First, we reduce the data into motion templates (Müller and Röder 2006). We design a set of 22 binary features to describe the movement of the arm. Second, we perform a phylogenetic analysis of the motion templates, in which we identify clusters within each timing condition. A comparison between clusters reveals differences in the coordination of the participants’ movements that correspond to the different performance strategies. Preliminary analysis has shown distinct clusters within all timing conditions that differ in specific features. For instance, we observe three groups of participants within the “natural” condition that differ in the flexion of the wrist and elbow. Besides our findings we will present the details of the methodology, which can be applied in the study of music-related movements beyond the scope of this project.

• Câmara, Guilherme Schmidt; Nymoen, Kristian & Danielsen, Anne (2019). Timing is Everything... Or is it? Part II: Effects of Instructed Timing Style and Timing Reference on Drum-Kit Sound in Groove Performance.
• Câmara, Guilherme Schmidt; Nymoen, Kristian; Lartillot, Olivier & Danielsen, Anne (2019). Timing is Everything... Or is it? Part I: Effects of Instructed Timing and Reference on Guitar and Bass Sound in Groove Performance.
• Câmara, Guilherme Schmidt (2018). Presentation of preliminary findings: Effects of Instructed Timing on Guitar and Bass Sound in Groove Performance.
• Câmara, Guilherme Schmidt (2018). Presentation of Mocap Component of Performance Experiments from the Timing and Sound in Musical Microrhythm (TIME) project .
• Câmara, Guilherme Schmidt (2018). Original concert performance with funk/soul ensemble "Baba Soul & The Professors of Funk", Oslo World Music Festival 2018.
• Martin, Charles Patrick; Gonzalez Sanchez, Victor Evaristo; Kelkar, Tejaswinee; Zelechowska, Agata; Berggren, Stig Johan & Hopgood, Christina [Show all 13 contributors for this article] (2017). Ensemble Metatone - Improvised Touchscreen Performance.
• Danielsen, Anne; Nymoen, Kristian; Haugen, Mari Romarheim & Câmara, Guilherme Schmidt (2017). Project presentation: Timing and Sound in Musical Microrhythm (TIME).
• Câmara, Guilherme Schmidt; Danielsen, Anne & Nymoen, Kristian (2021). Timing Is Everything . . . Or Is It? Investigating Timing and Sound Interactions in the Performance of Groove-Based Microrhythm. Universitetet i Oslo. Full text in Research Archive Show summary

  This thesis investigates the expressive means through which musicians well versed in groove-based music shape the timing of a rhythmic event, with a focus on the interaction between produced timing and sound features. In three performance experiments with guitarists, bassists, and drummers, I tested whether musicians systematically manipulate acoustic factors such as duration, intensity, and volume when they want to play with a specific microrhythmic style (pushed, on-the-beat, or laid-back). The results show that all three groups of instrumentalists indeed played pushed, on-the-beat, or laid-back relative to the reference pulse and in line with the instructed microrhythmic styles, and that there were systematic and consequential sound differences. Guitarists played backbeats with a longer duration and darker sound in relation to pushed and laid-back strokes. Bassists played pushed beats with higher intensity than on-the-beat and laid-back strokes. For the drummers, we uncovered different timing–sound combinations, including the use of longer duration (snare drum) and higher intensity (snare drum and hi-hat), to distinguish both laid-back and pushed from on-the-beat strokes. The metronome as a reference pulse led to less marked timing profiles than the use of instruments as a reference, and it led in general to earlier onset positions as well, which can perhaps be related to the phenomenon of “negative mean asynchrony.” We also conducted an in-depth study of the individual drummers’ onset and intensity profiles using hierarchical cluster analyses and phylogenetic tree visualizations and uncovered a diverse range of strategies. The results support the research hypothesis that both temporal and sound-related properties contribute to how we perceive the location of a rhythmic event in time. I discuss these results in light of theories and findings from other studies of the perception and performance of groove, as well as research into rhythm and microrhythmic phenomena such as perceptual centers and onset asynchrony/anisochrony.

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