The Ruan and the YueqinMeasurement and analysis of sound radiation patterns

of the Chinese Ruanand the Yueqin

Florian Pfeifle // Musicological Institute // University of Hamburg

Overview

Ruan Yueqin

Overview

Ruan Yueqin

• Round resonance body • Round resonance body

Overview

Ruan Yueqin

• Round resonance body • Sound holes

• Round resonance body• One small sound hole

Overview

Ruan Yueqin

• Round resonance body • Sound holes• Bridge

• Round resonance body• One small sound hole• Strings coupled to body

Overview

Ruan Yueqin

• Round resonance body • Sound holes• Bridge

• Round resonance body• One small sound hole• Strings coupled to body

Different timbre!

Overview

Ruan Yueqin

• Round resonance body • Sound holes• Bridge

• Round resonance body• One small sound hole• Strings coupled to body

Different timbre!

Methods

Measurement• Minimal Energy Method

[Bader, JASA 2010]• Reconstruction of the sound

radiation • All instruments are

measured with a 11x11 microphone Array

• All depicted sound radiation are the result of a single measurement (a knock, or a string)

Modeling• Pseudo-Spectral Finite

Difference Scheme [Fornberg, 1996]

• Time-stepping with NVS-Algorithm

• Whole instrument geometries are modeled

MEASUREMENTSRuan

Spectrum of the back-plate

Spectrum of the back-plate325 Hz

Lighter color = higher sound pressure level

Spectrum of the back-plate

456 Hz

Spectrum of the back-plate702 Hz

Spectrum of the back-plate1015 Hz

Spectrum of the front-plate

Helmholtz Frequency (extended Rayleigh notation):

Spectrum of the front-plate317 Hz

Spectrum of the front-plate336 Hz

Spectrum of the front-plate406 Hz

Spectrum of the front-plate

451 Hz

Spectrum of the front-plate817 Hz

Spectrum of the front-plate578 Hz

Spectrum of the front-plate656 Hz

Spectrum of the front-plate1037 Hz

Air modes // One sound hole closed

Air modes // One sound hole closed

Ruan Intermediate Results

• Two peaks in the spectrum are air modes• Characteristic modes appear twice in the

spectrum: • Front-plate radiation only

Ruan Intermediate Results

• Two peaks in the spectrum are air modes• Characteristic modes appear twice in the

spectrum as: • Coupled air-front-plate radiation

First vs. second string

First vs. second string fundamental

96,8Hz

148Hz

First vs. second string first partial

First vs. second string third partial

MEASUREMENTSYueqin

Spectrum of the front plate

Spectrum of the front plate

233 Hz

Spectrum of the front plate

379 Hz 420 Hz

Spectrum of the front plate

530 Hz 684 Hz 1048 Hz

Intermediate Results

• The fundamental frequency of the Yueqins front-plate is lower

• Spectrum of the Yueqin is “smoother”• The Helmholz of the Ruan plays a crucial role

in the sound radiation• Other air modes of the Ruan are important

too

SIMULATIONRuan and Yueqin

Model of the Ruan without soundholes

Model of the Ruan with sound holes

Model of the Yueqin

Yueqin simulated sounds

• Yueqin without hole

• Yueqin with hole

• Yueqin with hole and frets

• Yueqin without air

Results

• The difference in timbre is linked to the presence of the front holes

• The air volume not only influences the sound radiation but also the vibrational behavior of the front-plate

• The position of the bridge influences the excited spectrum on the front-plate

Further Work

• Research the effect of the air volume and the sound hole of the Yueqin

• Research the interaction between the air and the front-plate

• Research and refine the boundary conditions for both front-plates

Further Work

• Research the effect of the air volume and the sound hole of the Yueqin

• Research the interaction between the air and the front-plate

• Research and refine the boundary conditions for both front-plates

Questions // Remarks?