Audio Enhancement of Physical Models of Musical Instruments Using Optimal Correction Factors: The Recorder Case

Konstantinos Bakogiannis,Dimitra Marini,Spyros Polychronopoulos,Georgios Kouroupetroglou

doi:10.3390/app11146426

Konstantinos Bakogiannis, Dimitra Marini + Show 2 more

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https://doi.org/10.3390/app11146426

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Abstract

A simulation of a musical instrument is considered to be a successful one when there is a good resemblance between the model’s synthesized sound and the real instrument’s sound. In this work, we propose the integration of physical modeling (PM) methods with an optimization process to regulate a generated digital signal. Its goal is to find a new set of values of the PM’s parameters’ that would lead to a synthesized signal matching as much as possible to reference signals corresponding to the physical musical instrument. The reference signals can be: (a) described by their acoustic characteristics (e.g., fundamental frequencies, inharmonicity, etc.) and/or (b) the signals themselves (e.g., impedances, recordings, etc.). We put this method into practice for a commercial recorder, simulated using the digital waveguides’ PM technique. The reference signals, in our case, are the recorded signals of the physical instrument. The degree of similarity between the synthesized (PM) and the recorded signal (musical instrument) is calculated by the signals’ linear cross-correlation. Our results show that the adoption of the optimization process resulted in more realistic synthesized signals by (a) enhancing the degree of similarity between the synthesized and the recorded signal (the average absolute Pearson Correlation Coefficient increased from 0.13 to 0.67), (b) resolving mistuning issues (the average absolute deviation of the synthesized from the recorded signals’ pitches reduced from 40 cents to the non-noticeable level of 2 cents) and (c) similar sound color characteristics and matched overtones (the average absolute deviation of the synthesized from the recorded signals’ first five partials reduced from 41 cents to 2 cents).

Highlights

Accepted: 8 July 2021The acoustic simulation of musical instruments using computer models is a pole of attraction for scientists of multidisciplinary fields [1,2,3,4,5,6,7,8]
We studied the enhancement of the generated signal of the physical modeling (PM) of a Hohner melody recorder with baroque fingering using the optimization framework
We proposed a method that enables the maximization of the physical modeling (PM) of musical instruments efficiency by applying the optimal correction factors and presented a case study of a specific commercial recorder

Summary

Introduction

The acoustic simulation of musical instruments using computer models is a pole of attraction for scientists of multidisciplinary fields (i.e., physics, informatics, musicology, etc.) [1,2,3,4,5,6,7,8]. Several digital sound synthesis techniques have been developed (e.g., sampling, spectral modeling, and physical modeling) [9]. Physical Modeling (PM) is the technique that, by simulating the instrument’s physical phenomena, can generate its sound. The audible result of this technique depends purely on the level of detail of the model. In the process of simulation, assumptions are made in order to simplify the model, which inevitably affects the final result

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Results

Conclusion