The sound radiation patterns of musical instruments represent a considerable part of the perceived room acoustics. For instance, regarding the current tendency of vineyard-type concert halls, the spectrum of the direct sound varies strongly depending on the listening position due to the sound directivity of the instruments. The virtual acoustics research group has conducted extensive studies on directivity of the symphony orchestra instruments. The results can be applied in room acoustic modeling, or for general understanding on the behavior of orchestra sound in performance spaces. A journal article on the studies of the results has been published in Acta Acustica united with Acustica in 2010 [1]. In contrast to many previous studies on the topic (e.g. [2,3]), here all instruments are measured as they are played in an orchestra on stage. Furthermore, the unchanged measurement setup is used with all measured instruments, thus the results are comparable with each other.

During measurements, the musicians were instructed to play two octaves of A major chord tones in the native playing range of the instrument separately with constant speed. The seven A major tones were recorded in three different dynamics. Thus, for all instruments the gathered data is by nature five-dimensional: directivity on a spherical surface is a function of frequency, played tone, and dynamics.

The directivity data contains results from 14 instruments, measured with 22 calibrated microphones based on a dodecahedron shape at approximately 2m radius from the source [4].

Instrument directivity measurement and results with the tuba

The research includes directivity studies using an equal measurements system for all common symphony orchestra instruments.

Five dimensions in a 2-D plot

The study employs a special plotting technique for presenting multidimensional directivity data.

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References

@article{patynen2010directivities,
	title = "{Directivities of Symphony Orchestra Instruments}",
	author = {P{\"a}tynen, J. and Lokki, T.},
	journal = "Acta Acustica united with Acustica",
	volume = 96,
	number = 1,
	pages = "138--167",
	year = 2010,
	comment = {Online [Ingenta]},
	keywords = "Concert hall acoustics"
}

@book{mey78,
	author = "J. Meyer",
	title = "Acoustics and the Performance of Music",
	publisher = "Verlag das Musikinstrument",
	year = 1978,
	address = "Frankfurt/Main",
	optannote = ""
}

@article{oto05,
	author = "F. Otondo and J. H Rindel",
	title = "A New Method for the Radiation Representation of Musical Instruments in Auralizations",
	journal = "",
	volume = 91,
	number = 5,
	pages = "902-906",
	year = 2005
}

@article{pat08,
	author = {J. P{\"a}tynen and V. Pulkki and T. Lokki},
	title = "Anechoic recording system for symphony orchestra",
	journal = "ACTA",
	year = 2008,
	volume = 94,
	number = 6,
	month = "Dec.",
	pages = "856-865",
	keywords = "Auralization,Room acoustic analysis"
}