In organs of any pretensions it became his custom to employ pressures of 8 to 10 inches for the Great and Swell chorus reeds and the Solo Tubas in his larger organs were voiced on 20 or 25 inches.
He introduced the "closed eschallot" (the tube against which the tongue beats in a reed pipe) and created a revolution in reed voicing. He has had many imitators, but the superb examples of his skill, left in English Cathedral and town hall organs, will be difficult to surpass.
Prior to the advent of Hope-Jones (about the year 1887) no higher pressure than 25 inches had, we believe, been employed in any organ, and the vast majority of instruments were voiced on pressures not exceeding 3 inches. Heavy pressure flue voicing was practically unknown, and in reeds even Willis used very moderate pressures, save for a Tuba in the case of really large buildings.
Hope-Jones showed that by increasing the weight of metal, bellying all flue pipes in the centre, leathering their lips, clothing their flues, and reversing their languids, he could obtain from heavy pressures practically unlimited power and at the same time actually add to the sweetness of tone produced by the old, lightly blown pipes. He used narrow mouths, did away with regulation at the foot of the pipe, and utilized the "pneumatic blow" obtained from his electric action.
He also inaugurated "an entirely new departure in the science of reed voicing." [4]
He employs pressures as high as fifty inches and never uses less than six. His work in this direction has exercised a profound influence on organ building throughout the world, and leading builders in all countries are adopting his pressures or are experimenting in that direction.
Like most revolutionary improvements, the use of heavy pressures was at first vigorously opposed, but organists and acousticians are now filled with wonder that the old low-pressure idea should have held sway so long, in view of the fact that very heavy wind is employed for the production of the best tone from the human voice and from the various wind instruments of the orchestra.
Karl Gottlieb Weiglé, of Stuttgart, was a little in advance of many of his confrères in using moderately heavy pressures, but he departed from the leather lip and narrow mouth used by Hope-Jones and has obtained power without refinement.
In employing these heavy pressures of wind, increased purity and beauty of tone should alone be aimed at. Power will take care of itself.