An electromechanical keyboard instrument developed in Washington, DC, and Holyoke, Massachusetts, between 1894 and 1911 by Thaddeus Cahill (b Mount Zion, IA, 18 June 1867; d New York, 12 April 1934). Three instruments were completed, none of which fully embodied the construction specifications contained in Cahill’s five American patents. Cahill applied for a patent in 1895 and began to construct the first model of the Telharmonium, a small prototype (weighing 6·35 tonnes) for the later versions. The sound-generating system was based on the tone-wheel principle: a rheotome – a rotor with alternate conducting and insulating sections – in contact with metal brushes. The rheotomes were mounted on 12 shafts, one for each note of the octave. Each shaft bore rheotomes that would produce the fundamentals and various harmonics of one note of the scale over several octaves. The shafts were powered by belts driven by a constant-speed motor. A large dynamo supplied current directly into the mainframe. The current travelled through the pitch shafts into the conducting sections of the rheotomes, so that the brushes received interrupted electrical signals. The harsh waveforms thus produced were filtered by transformers and combined into a composite signal, which was transmitted along telephone wires to receivers fitted with large horns. The instrument was played from a keyboard. A hammer mechanism, dependent on key velocity, controlled volume by moving a transformer coil.
In 1903 Cahill moved to Holyoke and began to construct the second Telharmonium, a much larger commercial model intended to supplant orchestral instruments. The rheotomes were replaced by 145 alternators, or dynamos, which generated smoother waveforms and yielded greater current output. The alternators were mounted on eight steel shafts, permitting the instrument to play in only eight keys. For timbre control, switches and rheostats controlled the volume of the harmonics (some of which also served as notes of the scale for the missing four shafts). The 670-kilowatt output of this musical power plant could fill many rooms with sound. The three five-octave, 153-key manuals allowed operation in equal temperament and just intonation. The apparatus weighed 200 tonnes and cost $200,000.
The instrument was completed in 1906 and installed in Telharmonic Hall, New York, on Broadway at 39th Street, where four daily concerts drew large crowds. The output, fed into a cable along Broadway and Fifth Avenue, supplied the music to receivers in restaurants, theatres and homes (Mark Twain was the first residential subscriber). Before long the inventor Lee de Forest was broadcasting the music in his early radio experiments, but it was of unsatisfactory quality: the players (often two performed together) had little opportunity to practise at the awkward keyboard but were obliged to give daily performances. Technical imperfections included a reduction in volume as voices were added, an exaggerated staccato, a ‘growling’ effect in the bass and a constant tone quality that was said to be highly irritating. Financing dried up with the Panic of 1907, and the programmes turned into musical freak shows to sustain interest. The hall closed in 1908, but Cahill returned to New York three years later with the third Telharmonium, which was installed on West 56th Street; a cable was run to a hotel on Columbus Circle and down Broadway to Carnegie Hall. Lack of public interest stemmed from growing awareness that the development of wireless was rendering the Telharmonium obsolete, and no commercial service was established. In 1914 Cahill’s company went bankrupt. There are no known surviving artefacts or recordings. The first instrument was kept by the inventor’s brother in New Jersey for many years. His attempts to find a home for it were unsuccessful, and it is likely that it was scrapped on his death in 1962. The second Telharmonium had been shipped back to Holyoke in 1908 and scrapped in 1911. The third was probably sold for salvage in 1918 when the West 56th Street premises were vacated. The Telharmonium was a precursor of the Hammond organ (1934), which used small rotating magnetic generators similar to Cahill’s tone wheels. The Telharmonium marked the beginning of comprehensive musical synthesis, for Cahill understood and utilized many of its basic principles: additive synthesis to create timbre, a touch-sensitive keyboard to control volume, envelope control, dynamic control, filtering and mixing.
A.S. McAllister: ‘Some Electrical Features of the Cahill Telharmonic System’, Electrical World, xlix (1907), 22–4
‘The Telharmonium: an Apparatus for the Electrical Generation and Transmission of Music’, Scientific American, xcvi (1907), 210–11
‘Electrical Transmission of Music: Developments in the Cahill Telharmonic System’, Electrical World, lv (1910), 1059
E.H. Pierce: ‘A Colossal Experiment in “Just Intonation”’, MQ, x (1924), 326–32
W.A. Johnson and others: ‘History of Electronic Music, Part One’, Synthesis [Minneapolis], i/2 (1970–71), pt 3, p.15; pubd separately (n.p., n.d.)
T.LaM. Rhea: The Evolution of Electronic Musical Instruments in the United States (diss., George Peabody College, Nashville, TN, 1972), 5; section rev. as ‘The Cahill Telharmonium’, Contemporary Keyboard, iii (1977), no.2, p.47; no.3, p.55
R. Weidenaar: Magic Music from the Telharmonium (Metuchen, NJ, 1995)
REYNOLD WEIDENAAR