58
68
Spécial « Congrès Acoustics 2012 »
Acoustical and musical properties of the Deskford carnyx reconstruction
Brassiness potential of the carnyx
John Kenny has demonstrated that the reconstructed
Deskford carnyx can readily generate the characteristic
«brassy» timbre arising from nonlinear distortion in the
propagation of sound within the instrument. To examine
this effect, a setup similar to that used in measuring the
transfer function was used. A sine wave of frequency
1 500 Hz was injected into the mouthpiece of the instru-
ment, and the spectral centroid of the sound radiated
from the open mouth was calculated as a function of the
input pressure. The experiment was again carried out in
an anechoic chamber.
The spectral enrichment with increasing input pressure
illustrated in Figure 11 is similar to that found in narrow
bore trombones [6]. The brassiness potential parame-
ter, calculated from the bore profile of the instrument, is
B = 0.69, which is also a typical value for instruments of
the trombone family.
Fig. 11: Spectral centroid of radiated sound, with input sinusoid at
1500 Hz, as a function of rms input pressure
Barycentre spectral du bruit rayonné avec une sinusoïde
d’entrée à 1 500 Hz comme une fonction de la pression
rms d’entrée
Conclusion
Most of the natural notes of the Deskford carnyx recons-
truction identified by John Kenny can be readily unders-
tood in terms of the measured input impedance, since
each is fairly close to one of the input impedance maxima
of the instrument. The lowest two notes, D#1 (39 Hz)
and D#2 (77 Hz), are more diffcult to understand. There
is no resonance close to either of these frequencies.
It is possible that each has the character of a pedal note,
with the second harmonic of D#2 and the fourth harmo-
nic of D#1 being supported by the resonance at 163 Hz.
This hypothesis is consistent with the fact that D#1 is a
weaker note than D#2.
In describing the musical playing properties of the Deskford
carnyx reconstruction, John Kenny has emphasised the very
large dynamic range which is possible on the instrument,
ranging from the quietest pianissimo to a brassy fortis-
simo. The fact that very loud playing is possible is consis-
tent with the wide bore of the instrument, which results
in a high transfer function to the radiated sound field, and
with the relatively effcient radiation of sound in the percep-
tually important frequency range around 3 kHz.
The brassiness potential parameter is also fairly large,
encouraging the generation of high frequency compo-
nents which are efficiently radiated.
Comparisons of the Deskford carnyx reconstruction with
the reconstruction based on the Tintignac discovery has
only recently become possible. One interesting issue is
the design of the mouthpiece : it is reassuring to find
that the mouthpiece which is an integral part of one of
the Tintignac pieces is very similar in its internal profile
to the mouthpiece selected for the Deskford instrument,
with almost no throat.
The Tintignac instrument has a more sharply tapering
conical bore than the Deskford reconstruction, resulting
in a set of resonances significantly closer to a harmonic
series [3].
Whether the Deskford carnyx reconstruction is a close
approximation to the 2000 year old original instrument is
a question unlikely to be answered. Further investigation
of the Tintignac horde may shed further light on the nature
of instruments of this type, although it should be borne
in mind that the carnyx was apparently made and played
over a period of several centuries, and no doubt existed
in various different forms during that time. Reconstruction
projects inevitably involve some speculation, but as John
Kenny and other musicians have demonstrated they can
result in instruments capable of playing a valuable role in
the musical culture of the present day.
Acknowledgments
The authors gratefully acknowledge helpful discussions
with Joel Gilbert and assistance with experimental work
and data analysis by Shona Logie and Arnold Myers.
References
[1] F. Hunter, “The carnyx in iron age Europe”, The Antiquaries Journal 81,
77-108 (2001)
[2] D. M. Campbell, T. MacGillivray, “Acoustics of the Carnyx” in Studies in
Musical Archaeology II: Music Archaeology of Early Metal Ages Ed. E. Hickmann,
I. Laufs, R. Eichmann, Deutsches Archaeologisches Institut, 357-363 (1999)
[3] J. Gilbert, E. Brasseur, J.-P. Dalmont, C. Maniquet, “Acoustical evaluation of
the Carnyx of Tintignac”, Proc. Acoustics 2012 Nantes, France (2012)
[4] ARTIM G.m.b.H.;
[5] M. Campbell, C. Greated, The Musician’s Guide to Acoustics, Oxford University
Press, London (1998)
[6] A. Myers, B. Pyle, J. Gilbert, D. M. Campbell, J. Chick, S. Logie, “Effects of
nonlinear sound propagation on the characteristic timbres of brass instruments”,
J. Acoust. Soc. Am. 131, 678-688 (2012)
F
Do Do# Ré Ré# Mi
Fa Fa# Sol
Sol# La La# Si
UK
C C# D D# E
F
F# G G#
A
A# B
Equivalence des notes de musiques français/anglais
