Experimental characterization of the steel tongue drum

The steel tongue drum (also known as hank drum) is a relatively new musical instrument (2007) in the pitched percussion family, generally made from a metal sheet or from the base of a tank. Several tongues are cut on its surface, making the instrument capable of producing different tones depending on the shape of the tongues. The sound produced has interesting features such as a long decay and a rich and colourful harmony that differentiates this instrument from other mallet instruments as chimes, xylophones or marimbas. The main objective of this work is to present an acoustical characterization of this instrument from direct experimental measurements. Using a class-A measurement system composed of two microphones, a multichannel data acquisition system with pc interface and a computer, the sounds produced by each one of the single tongues were recorded and analysed. Spectrograms were obtained covering from the attack to the decay of each note of the drum. This work is a first step towards the physical characterization of this musical instrument and shows the presence of the harmonic interference between the notes that gives to the steel tongue drum its characteristic sound.