2 December 2017. Click About This Website for update list.
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site is mirrored at www.colinpykett.org.uk
over eighteen years the most stable and extensive resource on the Internet
for pipe and electronic organs
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 4
Ĺ hours of music
played on the three manual organ below and the Prog Organ
virtual pipe organ here?
!! NEW ARTICLE !! - A
technique for simplifying parameter estimation in synthesised pipe organ sounds
A major problem in synthesising musical sounds lies in assigning values to the large number of parameters associated with each note. For example, in additive synthesis the relative amplitudes of each harmonic have to be specified together with the way each one varies throughout the sounding epoch. Or in a physical model of an organ flue pipe the parameter set describing the aerodynamics of the pipe foot and mouth, as well as the properties of the resonant air column, likewise becomes inconveniently large. In such cases allocating values to the parameters to achieve a desired timbre is therefore a major challenge. The problem is particularly difficult for the organ because each stop is in effect a different instrument with a distinct character. Furthermore each stop also comprises many separate notes which all have to be individually voiced. This results in a serious parameter overload and estimation problem in current synthesis techniques for simulating the pipe organ.
This article describes a method which requires only four parameters to define the steady-state timbre of any organ pipe. This is very much smaller than the parameter lists used in traditional tone models whose sizes might run to fifty or more. Furthermore the parameters are intuitive rather than arcane descriptors of sounds, thus it is unnecessary for a voicer or tonal designer to be a specialist in digital music.
A complete digital organ simulated in this manner is described together with sound files demonstrating the wide range of sounds it can produce.
RECENT ARTICLE -
radiation field of organ pipes
This non-mathematical article shows that the surroundings of an organ pipe react so strongly on it that a flue pipe would not work at all if the adjacent atmosphere did not respond as it does, and reed pipes would sound completely different. Thus a pipe is not an isolated entity which operates independently of the environment it is in. The pipe-atmosphere interface is also responsible for its end corrections, and furthermore it influences radiating efficiency as a function of frequency. This affects the proportion of a pipe's sound energy contained in its early harmonics compared with the high ones, which strongly influences its subjective timbre or tone
It is shown that all these effects follow from the fact that most of the pipe's energy does not propagate to long distances in the far field but instead it merely circulates closer to the pipe. In this near field region the energy is periodically stored in local air masses and then returned to the pipe during each oscillation cycle. The re-entry of energy causes the reflections which maintain the standing wave inside the pipe. The energy circulation process is also explained in terms of acoustic impedance, a term widely used but less well understood. An important aspect is that organ pipes must be poorly matched to their environment in terms of impedance if they are to function, thus they are inefficient generators of acoustic energy.
It is generally known that a flue pipe is a coupled system insofar as the intimate interaction between the air jet at its mouth and its resonant air column controls how it works. However it is less well appreciated that the interaction between the air column and the atmosphere is just as important. In other words an organ pipe is a triply-coupled system, the triplet being the air jet, the resonator and the atmosphere. It is therefore remarkable that one of the most ancient and apparently simple musical instruments is so complicated and whose secrets have yet to be fully revealed.
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.
above is an experimental digital organ which simulates many different pipe
organs (Prog Organ).
the article entitled Re-creating
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).
things they say:
like a town hall organ"
I didn't know better, I would say this was an Edwardian instrument with its
choir organ spoiled by turning it into a baroque-type positive forty years
later - much like many British pipe organs in other words. I love
finest electronic organ I have ever played, simply because it has a genuine
warm Romantic sound rather than spit and chiff just for the sake of
impressive - but lacking the proper starting and ending transients"
draw a stop and it sounds just like you expect it to"
nice Colin. I'm so jealous"
an engineer and I know how you do it, but not how you do it so well"
how the great diapason chorus can stand on the Claribel alone"
reeds are lovely"
you take a picture? I'm writing an article for an organ magazine and I
want to be seen at this splendid console"
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.
Canzona in D minor. BWV 588. (J S Bach)
- 5.51 MB/6m 1s
Vom Himmel kam der Engel
Schaar. BWV 607. (J S Bach) - 1.5 MB/1m
jubilo. BWV 608. (J S Bach)
- 1.2 MB/1m 19s
Minuet in D (John Stanley) - 1.70 MB/1m 51s
Choral Song (S S Wesley)
- 3.00 MB/3m 16s
Church Bells (S S Wesley) - 3.54 MB/3m 52s (also available here
played on a simulated Wurlitzer theatre organ)
Andantino in G minor (Franck)
- 5.59 MB/6m 6s (also available here played on a simulated Cavaillť-Coll
- 4.72 MB/5m 9s
Fantaisie in E flat (1st part)
(Saint-SaŽns) - 1.85 MB/2m 1s
Pastorale from Sonata no. 1 in D
minor (Guilmant) - 5.3 MB/5m 47s (borrows
the Vox Humana from the theatre organ!)
Monologue I in C
- 2.02 MB/2m 12s
III in E (Rheinberger) 3.01 MB/3m 17s
Fughetta no. 8
in A (Rheinberger) - 2.55 MB/2m 47s
Chorale Prelude on
"Eventide" (Abide with me)
C H H Parry -
3.92 MB/4m 16s
on "Abridge" (Be thou my
guardian and my guide) Thomas Adams - 2.85 MB/3m
In Tune with Heaven (Alan Gray)
- 2.75 MB/3m 0s
Chanson de Nuit
(Elgar) - 3.28 MB/3m 35s
- 3.86 MB/4m 13s
(Edward MacDowell) - 2.56 MB/2m 48s
To A Wild Rose
(Edward MacDowell) - 1.72 MB/1m 53s **
To be sung of a
summer night on the water (Delius)
- 1.98 MB/2m 10s
Andante in D (Alfred
Hollins) - 7 MB/7m 39s
- 3.69 MB/4m 2s
Berceuse (Vierne) - 3.37 MB/3m 41s
Freu' dich sehr, O meine Seele
(Karg-Elert) 1.79 MB/1m
O Gott, du frommer Gott
(Karg-Elert) - 2.19 MB/2m
Adagio in E
- 5.06 MB/5m 31s
- 2.34 MB/2m 31s
Played on the theatre organ
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