Many different factors influence how the kettle of each timpani will sound; the many possibilities with regard to the size, shape, construction, bearing edge (lip), thickness and composition of each bowl all influence the sound of the drum. Over the hundreds of years of the history of the timpani as an orchestral instrument, there has been much documented about the steady increase in the diameters of each drum. Timpani makers were also experimenting with the depth of the bowl, and how changing the ratio between these two factors, diameter and depth, affected the sound. For baroque timpani, where the depth and diameter are often close to equal, the sound of the drum is clear and direct. A contributing factor in the case of baroque timpani is the tension on the skin, which is less because of the smaller diameters.

With timpani of the Dresdener design, the drum’s diameter and depth increased at an equal rate, so that shape and profile of the kettle, either hemispherical or parabolical, remained more or less the same. The Viennese timpani on the other hand kept the same diameters as from early romantic times, but the depth of the kettle increased dramatically giving it something of an egg-like shape, or that of a vase (this design of timpani can be seen in the televised concert given by the Vienna Philharmonic every New Years Day). In this way was the volume of the drum increased – but not its diameter – producing a full, round sound which is still very defined and focused, and impossible to overplay.

‘The fundamental difference [of the Viennese timpani] to the Dresdner timpani consists of the circumstance, that the skin is not drawn down over the kettle at the tuning, but the free swinging kettle is moved up an down.’ – Prof. Wolfgang Schuster, maker of Viennese timpani

Dieter Dyk - ‘One can with whole strength can play it [the Viennese timpani] in the largest Fortissimo – still of course in a musical way - without it the sound becoming overly loud, ugly or noisy.’[1]

The sound of these drums has also been described as “dark”, and so maybe the depth of these kettles contributes to this tone colour, as timpani with “multi-elipse” shaped kettles (straight sides angling inwards before rounding out at the bottom, see below) have also been said to have this type of sound. This shape of kettle is what is seen in "Dresden" style timpani, manufactured by Ringer, Adams and Kolberg, among others.

A parabolic reflector is the most effecient shape for the reflection of light waves, and some would say that this also holds true of sound waves. The curve of a parabola is such that all waves are reflected through a single focal point. The original Ludwig balanced action timpani were built with parabolic kettles and many, if not all, balanced action timpani available today also use this kettle shape. Finally note the distinctive shape of the Viennese timpani, egg shaped but still basically a parabola.[2]

Multi-elipse or cambered bowl


Viennese "Hochrainer" timpani

Parabolic bowl (Concorde)

Baroque timpani (Boosey & Hawkes)

Different Shapes of Timpani Kettles

With regard to how each kettle is constructed, there are two common methods. One entails the pulling of a single sheet of copper over a mold, creating a kettle that is not of uniform thickness, and in the other method the sides and bottom of the kettle are formed from separate sheets of copper which are then joined, a process which may inhibit the vibration of the resulting kettle.

‘When you shape a kettle by spinning [or stretching] one single piece of copper, the result is a kettle with a very thick bottom but thin sides, which is not able to resonate evenly’[3] Steve Schiffer, D. Picking & Co. (USA)

In the second half of the 20th century scientists began looking at musical instruments, applying objective tests to determine how a “good” sound is created. For the timpani kettle, they spoke of ‘ideal depths’ and ‘proper reflection of sound’. But the scientific information available on bowl acoustics and the affect of design and construction on the sound is scarce and often contradictory.

So we look to the players, who make little mention of construction processes, or scientific models, but instead speak of how the shape and the thickness of the kettle contribute to the sound of the drum. Conical shaped kettles, such as those of the Ringer design, are said to have a more focused and bright tone. Such kettles, also referred to as “parabolic”, have a shallower curve in the shape of the base of the kettle, which some players also attribute to giving the drum a darker and heavier sound. On the other hand timpani with a more hemispherical curve at their base give a ‘round, full and warm sound’.

The thickness of the kettle has a major impact on how the instrument is able to support the sound that the timpanist wishes to produce. One maker, Christoph Dörfler, whose instruments are designed along the lines of the Ringer timpani, builds the larger timpani with a thicker kettle to support the volume of sound often required from these drums, and uses thinner copper for the smaller drums so the sound is not thick and tubby.

Dieter Dyk -‘Thin material : more sensitive in soft passages, not so strong in fortissimo. Thick material: stiff sound played softly, with no good attack up to mezzo forte, but very strong in fortissimo.’

The bearing edge (or rim or lip) of the kettle, being the point where the skin meets the kettle, and also the point at which the skin is stretched, giving it tension, has an affect on the shape, or definition of the sound. A sharp or hard lip will produce a much clearer and more articulated tone than a soft lip, which makes the shape of the tone rounder.  Again the bearing edge can be tailored to the size of the drum; a rounder bearing edge on larger timpani gives a full sound to the low notes, with sharper bearing edges on the higher drums producing a more defined articulation.

Maarten van der Valk The lip has an influence by how the skin folds over the whole timpani. I believe that with goat skin for instance a thicker lip works better for the sound, rather than a thin lip’

Finally regarding the materials used, the kettles of almost all professional timpani are made of copper, a metal chosen for its ability to resonate with a full and round tone (brass kettles also exist). For the older timpani, which were produced individually by coppersmiths, a thorough hammering of the kettle to bring out the richness of the drum sound was considered a very important part of the construction process. Many of these drums, considered vastly superior to their factory produced counterparts, are still used in orchestras today.

Peter Offelder – The form and the hardness of the kettle make the sharpness of the tone. Also the hammering!!’

Many manufacturers also produce drums with fiberglass kettles, but their sound is dull, no strength, no real power’ and these instruments are only used by amateur ensembles such as school bands.

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[1] Dyk, D.  Of Calf Skins, Goat Skins and Other Coincidences

[2] Thanks to Jim Atwood for his assistance in explaining parabolic and other kettle shapes

[3] Stotz B., A Century of Timpani Bowl Building, Percussive Notes (August 1993) p. 68



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