Robert Wornum - Harmonic Uprights and Equal Tension

Harmonic Uprights and Equal Tension

By 1813 Wornum introduced a second upright design with vertical strings, measuring about four feet six inches tall (137 cm), that he called the "harmonic" which is generally considered the first successful cottage upright. Low vertically strung uprights with similar construction had been introduced with patented features in 1800 by Matthias Mueller in Vienna and John Isaac Hawkins in Philadelphia and London. Hawkins' in particular contained a similar action to the one shown in Wornum's 1809 patent, and the highest three octaves were strung with one size wire under the same tension in the same fashion as Wornum's 1820 patent, but both of these instruments also were more unusual than the cottage upright in tone and construction. Mueller's piano was described in the 1810 Oekonomische Encyklopädie as having a tone similar to a basset horn, and he offered a tandem model for performing duets he called the Ditanaklasis while Hawkins' piano featured a complete iron frame with an open back, a large, independent sounding board, and bass strings in the form of coil springs and it included mechanical tuners, a retractable keyboard, and a metallic upper bridge. Hipkins account of Hawkins' instrument in the 1890 Encyclopaedia Britannica described that it was "poor in the tone."

In 1820 Wornum patented a system of equal tension for pianos (and "certain other stringed instruments") that he specified would be achieved by employing "one size steel wire throughout", and in the shortened wrapped bass strings also by adjusting the size of the windings. According to the report of the patent in The Quarterly Musical Magazine it was intended to prevent the falling of the middle and upper octaves which the article described were the result of the usual practice of employing different tensions and sizes of wire in different parts of the piano, and the author reported that by his method Wornum was able to produce tones that were "firm, sonorous, and brilliant, and their standing warranted the highest opinion of the principle"; the review in The London Journal of Arts and Sciences predicted, however, that "if it ever be brought into use" it would "give a bad tone to the upper part of the instrument", and among the objections the reviewer anticipated, he claimed that it would be difficult to determining string lengths using Wornum's method, as well as in "procuring wires all of one size".

Alfred Savage, who wrote several letters on piano construction published in the Mechanics' Magazine in the early 1840s, stated that this system had the advantage of standing in tune better than any other, but that its tone was unequal across the compass: he described that using a thicker size wire would result in a want of vibration in the treble, whereas a thinner wire would want of firmness and fulness in the bass, and attributed the difference to the stiffness of the wire in relation to the length of the strings. Another correspondent on pianos who signed as "The Harmonious Blacksmith" wrote in an 1871 letter to the English Mechanic and World of Science that his "late friend" Wornum had used no.15 wire throughout, which in the 1820s and 1830s was at least four sizes larger than the wire normally used for the highest notes and several sizes larger even than those in the much longer and higher tensioned scales used at the time of the article, and he described that it gave "a very good treble, but a very poor tenor and bass." Wornum used this scale at least for the full term of the patent but it never came into more general application.