Last updated: 24 May 2013. Click About This Website for update list.
For over thirteen years the most stable and extensive reference source on the Internet for pipe and electronic organs
The hub of this site is the Complete Articles page which gives you instant access to many detailed articles dealing with numerous technical aspects of both pipe and electronic organs. Use the Google search box below to quickly identify areas of interest. While browsing, why not also listen to over three hours of music played on the three manual organ below and the Prog Organ virtual pipe organ here?
The church of St Mary Ponsbourne in Newgate Street village near St Albans in Hertfordshire, England, contains an authentic and historic English organ built in the mid-Victorian era by the well known firm of J W Walker in 1858. This article describes how its sound was captured digitally for posterity on a virtual pipe organ (Prog Organ), just prior to a major overhaul due to commence in April. Some audio examples of the result are included.
COMING NEXT - End corrections, natural frequencies, tone quality and the physical modelling of organ pipes
Most people know that organ pipes have an 'end correction' which makes them sound flatter in pitch than simple theory suggests based on their physical length. Organ builders have developed a good empirical understanding of this effect over many centuries so they can make pipes of the correct length, but a satisfactory theoretical treatment still remains elusive. This is partly because one also has to understand the natural resonant frequencies possessed by an organ pipe - these are quite separate both in theory and practice from the harmonics we hear in the sound it emits. The link between the two phenomena is that each natural frequency has its own end correction which is different from all the others. Because the interaction between the natural frequencies and the harmonics materially affects the timbre or tone quality of the pipe, it follows that the physical mechanisms of the end correction underlie not merely the tuning of a pipe but its subjective effects as well.
This article will present the results of some research which demonstrates many aspects of a complex matter. However it is non-mathematical, and it also describes a novel experimental technique which reveals the natural frequencies of a pipe. The results are related to the work of other authors, not all of which is confirmed. This is important to refining the physical models of sound generation in organ pipes which are used in synthesisers and digital instruments.
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The picture above is of a test rig used for experiments on pipe organ valves, such as those described in the articles entitled Calculating Pallet Size, Touch Relief in Mechanical Actions and Response Speed of Electric Actions. These can also be accessed from the Complete Articles page where summaries are also available.
This electronic organ is a dual purpose instrument containing both "straight" and "theatre" voices, designed and made by the author. It is tuned to the author's Dorset Temperament with the addition of some impure octaves as described in Keyboard Temperaments with Impure Octaves. A full specification is available for download here (PDF file, 117 kB).
The things they say:
These recordings span some years and they were made in various rooms and auditoria. The older tracks were made using analogue equipment and some were recorded acoustically using microphones, hence the occasional noises due to piston thuds and page turns, etc. Other tracks were captured electrically. All are of real players performing in real time - no synthetic MIDI 'performances' here. I have not got round yet to normalising the volume settings of all the tracks so they are compatible with each other, therefore you might wish to adjust the volume between tracks depending on which ones you select. Do not be alarmed if some tracks appear to start with an excessive noise level - this simply means they were recorded at a higher level than others. Just turn the volume down to suit. In any case, it is a wise precaution to always begin playing each track at a low level to protect your audio equipment and your ears from unexpectedly high signal levels when the music begins. Although the instrument has 13 ranks of theatre organ voices in addition to its 'straight' sounds (see specification), copyright considerations preclude the inclusion of much theatre-style music here. Playing time 1 hour 35 mins approx.
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