Why Is The Sound Of A Pipe Organ Better?
by Scott R. Peterson, President
Peterson Electro-Musical Products, Inc.
Alsip, Illinois
Pipe organ builders are often asked what makes the sound of a pipe
organ better than that of electronic organs which utilize today's
sophisticated digital sampling technology. After all, if a high-tech
recording is made of an organ pipe, and measurements show that the
wave forms produced by playback of the recorded note look like the
wave forms produced by the actual pipe, what difference would be
heard? Is the difference in sound between an electronic organ and a
real pipe organ so subtle that only trained musicians would appreciate
it?
Clearly, a pipe organ has many tangible advantages over electronic
organs, such as visual beauty, longevity, and usually a superior
quality of materials employed. The pipes, chests, console,
structural and decorative elements are built with a level of
craftsmanship that has grown rare. Modern solid state switching,
combination action, MIDI interface, and other control systems designed
specifically for pipe organs offer every conceivable feature and
convenience as required by even the most advanced organists. The most
popular of today's solid state control systems allow abundant
flexibility for future expansion or modification of the pipe organ to
meet needs years or decades into the future. Somewhat less tangible
but very real is the feeling one gets that a pipe organ is a
permanent, high quality investment in value rather than a device that
will be replaced in a decade or two. But what about the difference in
sound?
The key to this lies in the interaction of sounds that one hears when
many notes on multiple ranks of the pipe organ or electronic organ are
played together, and especially when this is further blended with the
singing of human voices. A good recording of a single note played
through a speaker may sound almost identical to the actual pipe that
was recorded. The authenticity of electronic organs played one rank
at a time can be very impressive indeed. However, a very significant
difference would be perceived by most people in a typical audience if
the same hymn or recital piece were to be played first on an
electronic organ and then on a pipe organ. Many would describe the
difference as more"thrill" or "fullness of sound" from the pipe organ
(not to be confused with greater loudness).
Scientists and engineers have determined that the musical sounds we
hear are collections of many separate simple vibrations called
"partials" reaching our ears after being produced by vibrating devices
like strings, wood or metal bars, reeds, or air columns in tubes such
as with organ pipes. Rather simple sounds like those of an orchestral
flute or flute organ pipe consist of only a few separate partials
occurring simultaneously, while richer or more complex sounds like
that of a violin string or a viola organ pipe are made up of a large
number of partials.
The partials of each note of a particular instrument or a particular
rank of pipes are usually related to each other in specific ways.
For example, each pipe in one rank may be characterized by the
slowest vibration (called the fundamental) being joined by another
partial three times as fast and another five times as fast, with
these higher two partials (called the third and fifth harmonics)
having a specific pattern and time rate of increasing and/or
decreasing loudness after the note is initially played and then held.
These dynamics can be carefully duplicated for each note of an
electronic organ, creating convincing substitutes for one real pipe
at a time. The reason for the profound advantage of the pipe organ
begins after these sounds leave the source and travel to the
listener's ears.
When several musical notes are produced by separate organ pipes, each
in their own location, every partial of each note creates its own
sound waves in the air, substantially independent of all other sound
waves. Each individual sound wave reflects from and may be partly
absorbed by the ceiling, walls, furniture, and any other element in
the room so that it takes it's own amount of time to reach the ears of
a listener. Because the human brain is so extraordinarily capable,
the differences in time that every sound wave takes to reach the two
ears and the "shading" of the listener's head between one ear and the
other are actually perceived and help to give a feeling of complexity
to the sound. This desirable effect is compounded when potentially
dozens of individual pipes are played simultaneously as the organist
builds a chorus of sounds. In contrast, each of a few loudspeakers on
an electronic organ produces a single sound wave that is the
electrically combined total of all the partials of all the notes
played through it. The complexity of reflections within the room and
the corresponding fullness and beauty of the resulting sound is much
reduced. The sound from the electronic organ tends to be more
directional. It is easy to point to the location of the speakers
whereas the pipe organ sound seems to fill the room from all over.
A further difference is that the electrical combining of partials from
the same note of more than one rank, or "coincident partials" of
different notes, leads to certain components of the total sound being
louder and some softer than when the sound of separate notes from
independent pipes are combined in the ear. If the partials being
combined electrically are very slightly different in pitch, an
unnatural "beating" sound results. These factors often lead to a
peculiar distortion common in many electronic organs, and at the very
least the electrical mixing creates a less pleasing blend of sounds.
While this explanation may seem complicated to some and abbreviated to
others, suffice it to say that the room-filling, supportive, thrilling
sound of an actual pipe organ may be appreciated by casual listeners
as well as aficionados of fine music. The tonal advantage of a
collection of pipes over a few loudspeakers is based on scientific
principles. Just as listening to a CD recording of a symphonic
performance is not the same as attending the live performance, there
is just no substitute for an authentic pipe organ for providing
meaningful, fulfilling music.
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