Erich-Thienhaus-Institut (ETI)
Filtern
Dokumenttyp
- Dissertation (3)
- Datenpublikation (2)
Sprache
- Englisch (5)
Volltext vorhanden
- ja (5)
Schlagworte
- Acoustics (3)
- Akustik (2)
- Auralization (2)
- Perception (2)
- Instrument blending (1)
- Music Performance (1)
- Musical ensembles (1)
- Nachhall (1)
- Reverberation (1)
- Room Acoustics (1)
Institut
The acoustic and auditory properties of individual musical instruments have been extensively studied over recent decades, however, their sonic interplay within a musical ensemble remains under-explored. Given their considerable importance across various fields, aspects of ensemble sound, such as blending of instruments, perceptual relevance of directivity of instruments, and the role of room acoustics, demand comprehensive evaluations and an interdisciplinary approach. This study aims to improve the perceptually motivated acoustic representation of instruments in joint performance in both real and virtual acoustic domains, by exploring different stages of these aspects in musically realistic contexts.
An explorative listening test with live string ensemble performance suggested that the characteristics of the acoustic environment considerably influence the blending of violins playing in unison. Combining methods of Machine Learning and Music Information Retrieval, a computational modelling approach is proposed to classify sound samples from an ensemble recording according to perceived blending. Proving this classification to be effective for monophonically rendered sound samples of two violins from in-situ environments, without requiring the individual source recordings marks a first step towards comprehensive blending modelling. Furthermore, the applicability of close-microphone recordings for auralization of a perceptually convincing ensemble sound was successfully demonstrated.
Advancing previous research in directivity perception, it could be demonstrated that the room acoustics have a greater impact on the orientation perception of sources than their directivity. By involving instruments with distinct radiation directivities in a variety of acoustic environments, the major acoustical parameters influencing the orientation perception have been explored. Examining musical instruments with their inherent dynamic directivity against loudspeakers in in-situ conditions showed that their distinction becomes obscured under specific acoustic conditions. These findings led to a pilot study on the perceptual relevance of high-order directivity modelling of individual sources forming an ensemble. Results indicate, that even with an increasing number of sources, their detailed directivity characteristics remain pivotal for auralizing ensemble performance.
The role of room acoustics in shaping the overall blending is shown to be dependent on the source-level blending. A computational model for predicting overall perceived blending in musical performance using source-level blending ratings and room acoustical parameters was suggested and validated. Analysis of its feature importance revealed that the room acoustic contribution to the overall blending impression is nearly as significant as the blending between instruments at the source level. By emphasizing and detailing relations between musical blending, directivity perception, and auralization aspects, this thesis contributes to the advancement of ensemble sound research and offers insights pertinent to music performance and perception research, virtual acoustics, and related fields.
The Zip file contains monophonically rendered sound files used in the source level blending evaluation. The sound samples provided are recorded from a violin ensemble performance at Detmold Concert House as a part of an investigation on the influence of acoustic environment on the impression of blending [1]. DPA 4099 clip-on microphones were used to capture individual violins in the performance. Each sound sample consists of two violin signals that were rendered by downmixing to a monophonic format at 44.1kHz/16-bit depth. The impression of blending between the two violins in each sample was rated by a group of trained listeners, and the results are provided in the description file. Please refer to the publication for more details on the performance of the violin ensemble. Also, please cite the publication if these samples are used for scientific evaluations.
[1] Jithin Thilakan and Malte Kob, “Evaluation of subjective impression of instrument blending in a string ensemble”, Fortschritte der Akustik - DAGA 2021 in Wien, pp. 524-527.
Bassoon Directivity Data
(2020)
Room acoustic conditions are an inherent element of every live music performance. They interact with the sound that is generated by the musicians, modifying the characteristics of the sound received by audience and musicians. While listeners usually play a passive role in the context of a live performance, musicians are part of a feedback loop composed by themselves, their instruments, and the room. The goal of this thesis is to characterize the effects of room acoustics in live performances, by studying the acoustical preferences of musicians and characterizing potential performance adjustments implemented by solo players while adapting their interpretation to the room acoustic conditions.
To conduct systematic experiments, a virtual acoustic environment that replicates acoustic conditions of real rooms in laboratory conditions is implemented. Room impulse responses of performance rooms are measured and parametrized using spatial measurement techniques. The responses are later resynthesized and convolved in real-time with the sound generated by a musician. The resulting sound is reproduced through a 3D loudspeaker set-up, allowing musicians to perform under replicated acoustic conditions of measured rooms in real-time. The system is used to conduct pilot studies on stage acoustics preferences of semi-professional trumpet players, and to study the impact of room acoustics on potential performance adjustments of live performance. To this end, musical pieces are recorded under different acoustic conditions and later analyzed. A second experiment is performed with organ players in the Detmold Konzerthaus. The reverberation time of the hall is modified using a reverberation enhancement system, and live performances are recorded under different acoustic conditions using a MIDI interface. Similarly to the trumpet players, the recordings are analyzed to evaluate the extent of the performance adjustments. Finally, listening tests are conducted to assess the perceived impact of those adjustments by listeners.
Results of the experiments suggest that musicians systematically adjust their performance to accommodate room acoustic conditions and listeners are generally able to perceive these changes. Trumpet players tend to decrease the sound level and sound brightness when exposed to longer and stronger reverberation. Some players adjust as well musical dynamics and aspects related to the tempo of their performance, although generalized trends are not observed. Dry environments are usually preferred to practice instrument technique, while longer reverberation times are preferred in concert conditions. Additionally, the presence of a sufficient amount of early energy contributes positively to the musicians’ comfort, regardless of the direction of incidence of this sound energy. Organ players are prone to modifying the temporal aspects of the performance, generally decreasing the overall tempo and increasing the length of breaks in more reverberant environments. The musical character of the played excerpts seems to play an important role, and while for some pieces changes are generalized and systematic, the performance of other pieces with soft dynamics and little contrast is generally less affected by room acoustics.
Reverberation is an important factor of the acoustics in a room. It influences the
acoustic perception of the listener and the performer. Each concert venue has its
specific acoustic properties. Numerous studies regarding these properties have been
conducted, mostly in real world or fully synthesized environments. However, both
acoustic quality and perception in concert spaces are still not satisfactorily explained.
The present thesis contributes new findings in the field of reverberation (late energy)
for concert spaces. Previous concepts are further refined and novel approaches
suggested. Several experiments are conducted in semi-virtual acoustics, namely real
rooms whose existing acoustics is altered by means of an electronic reverberation
system with loudspeakers. Thus, the possibility of changing the acoustic situation at the push of a button is offered, while the listeners’ visual and tactile perception remains the one from the real world environment. A lecture hall and a medium-sized concert
hall equipped with enhancement systems are the test environments. Three aspects of
reverberation are studied using this technique among others: reverberation level, spatial distribution of reverberation and the connection between signal dynamics and acoustics.
The related perceptual attributes reverberance, listener envelopment and perception of dynamics are investigated by means of listening experiments.
Following a qualitative investigation on enhancement systems, it is observed that
reverberance depends highly on reverberation level. The method of only assessing
decay time is not suffcient. An energy parameter such as strength must be included to
predict reverberance. A loudness-based reverberation analysis is further explored and found to perform well in principle, however the three loudness models investigated
differ noticeably. The direction of late reverberation in concert halls and the influence on the feeling of envelopment is further specified. Several tests show that the current
measure neglects late reverberation from behind and above which contribute to listener envelopment. Lastly, the connection between signal envelope or dynamics and room
acoustics is investigated, specifically regarding reverberation. Studies are conducted using, for example, a constant virtual orchestra source or a large pool of audio recordings from concert halls and opera houses. It is observed that reverberation alters the signal dynamic considerably, which is vital both in the context of acoustics and performance practice.