Creative Church Acoustics
Bolt Beranek & Newman, Cambridge, Mass.
Auspices of The Boston Chapter ofMembers:
The American Guild of Organists
John Ferris, A.A.G.O., Dean.Mr. Harold Wagoner, Architect,
Mr. David Klepper, Acoustical Engineer,
Mr. Lawrence I. Phelps, Organ Builder.
Mr. Phelps spoke substantially as follows:
Both Mr. Wagoner and Mr. Klepper have referred to the relative importance of music and speech in the church and they have indicated that the weighing in favor of one or the other varies considerably with the relative importance of ritual in liturgy and the cultural background, hence collective standards and taste, of the individual church community. Nevertheless I think we must all agree that nothing is more important at the time of the musical performance in a church building than the music and the quality of the performance and the projection of these to the ear of the communicants or listeners.
Certainly the spoken word has a basic importance in a church situation and every possible consideration should be given to maintaining a high rate of intelligibility throughout a church auditorium, but, if we are to arrive at ideal design solutions, we must have a clearer view of the reasons for music in the church. We must abandon as fast as practical the notion that music in the church is for the entertainment of those present.
We must understand that traditionally the making of music in the church has been virtually an act of worship, “an offering unto the Lord”, and that its purpose is not for the entertainment of those present but for their strengthening and elevation through their experiencing it. Music has not, and indeed cannot, usurp the office or importance of the spoken word, but music and the word have for centuries stood side by side, together with prayer, as the chief constituants of Christian worship. Mr. Wagoner's suggestion that possibly a variable or adjustable acoustical environment may offer the most ideal solution is a good one, but of course, the expense would be considerable and, in my opinion, except in very unusual circumstances, not justified, since excellent results in churches of moderate size can be, and are being achieved simply through good design. Through the use of design principles well known to acousticians and through the avoidance of acoustically troublesome shapes, architects can design rooms which can be left entirely free from treatment in involving any of the so-called “acoustical materials” which cause such harmful effects to both speech and music. Where the room is large enough to require it, speech intelligibility can be maintained, without loss of realism through the use of high quality electro-acoustic systems.
I am quite willing to admit that organ builders have done much to confuse matters and to retard progress through their insistence upon excessively long reverberation periods. This is not entirely justified by an historical approach. Earlier this afternoon, in his lecture on various aspects of concert hall acoustics Dr. Leo Beranek indicated that his very careful study of the acoustical properties of the world's great concert halls has led to the conclusion that listening areas, design primarily for performing romantic music should have longer reverberation periods than rooms primarily designed for performance of the baroque or classical literature.
The churches of almost any period were more reverberant than those rooms of the same period designed especially for listening to music, and, using the same method of evaluation as that used by Dr. Beranek in his analysis of concert rooms, we may state that liturgical practice requires considerably longer reverberation periods. We must admit that many European churches in which are found some of the finest examples of the organ organbuilders art have reverberation periods falling far short of those which have been demanded by some American organ builders. A rather short period is particularly typical of many of the churches housing the especially esteemed work of the North German organ builders as exemplified by the work of Arp Schnitger (1648-1719). When we consider this, together with the realization that there is surprising little worthy music for the church available to us from the romantic period, we are led to a position in which we expect something quite different from the church acoustics, so far as music is concerned, than the “cathedral roll” so endeared by of our colleagues in the field.
It is unfortunate that reverberation seems to be the one acoustical property of an enclosure that most organ builders and architects are aware of. Actually, while a considerable amount of reverberation is required for organ music and church music in general, a proportionately excessive decay rate is as harmful for musical clarity as it is for speech intelligibility. Much more important to the quality of the reception of a musical performance are those properties of a room which contribute to the efficient projection and distribution of sound throughout the room, and those properties which give the room the “natural” sound traditionally characteristic of a room of its particular dimensions. An overly “treated” room is always deprived of the properties which are as important to speech as to music, even though the treatment may still have left the room quite reverberant at certain frequencies.
I am sorry if my down-grading of the sole acoustical criterion used for so many years by other organ builders, that of reverberation, and my stressing as more important to the over-all quality and efficacy of a given acoustical environment, such items as projection, distribution, and natural harmonic balance in the responsiveness and decay rate of the room have caused Mr. Wagoner consternation. It has not been my intention to confuse, but to clarify. However, Mr. Wagoner can take some comfort in knowing that not only have other notable architects been similarly dismayed, but that 12 or 15 years ago, when I first posed these considerations, my organ building and acoustician friends alike were hard put to take me seriously. At that time some of these properties had been under study for years and auditoriums had been built which boasted of “perfect” projection, “uniform” distribution and “uniform” decay rate at all frequencies. Most of these examples, although “designed for Music” were absolutely horrid for music of any kind, and the organs that some of them housed were little more than freaks. These rooms were almost always acoustically dead, and musical performances in them a usually resulted in little more than “readings” because they lacked most all of those qualities which have traditionally brought joy and inspiration to the hearts of music lovers and performers. It was the nearly unanimous rejection of these rooms by musicians of note and their insistance that there were in existence older rooms that must set the standard, that finally caused acousticians to abandon the purely theoretical approach. Only when the full realization that scientific and engineering perfection did not necessarily make for musical perfection finally struck home, did acousticians began to learn to listen.
We have now reached the point where architects must learn to listen, or, what will probably be more fruitful, they must learn to listen to those acousticians, organ builders and musicians who have now virtually brought the science of acoustics to the verge of its becoming an art. Progress is certainly being made, and although it may be another decade or two before the art comes fully into its own, I personally am looking forward with eager anticipation to the appearance of Dr. Beranek's forthcoming book on concert hall acoustics, not because it will offer any real solution to acoustical design problems, but because it will probably, from what I already know of it, present the complete problem of auditorium design, in all its qualitative aspects, for the first time in print. Most of what Dr. Beranek will have to say in this book will be directly applicable to any church auditorium where high quality musical performance and listening will be of importance, and it is my earnest hope that when the complete problem is finally laid bare, the do-it-yourself tendencies so prevalent in many architectural offices, will be at last discouraged.
Since the middle 1920's, there has been underway in Europe, and, beginning a little later in the United States, an organ reform movement which, if simplified to its fundamentals, has been based on the realization that the romantic period produced virtually no important music for the church, even the great music for organ of this period being more generally of a symphonic character and not intended for church use (use in the actual worship service), and a reawakening to the great musical heritage of the church from much earlier periods. Accompanying universal organ reform, there have also been general liturgical reform movements instituted within the ranks of several important church organizations. At the risk of over simplification, we can say that these have been broadly aimed at purging from the church music much that is now considered to be of a secular, sensual, or purely sentimental nature. The reawakening to earlier traditions and the integration of the rich legacy of Christian music, left to us before the middle of the 18th Century, into the “culture” of today's living church, has required a patient search that we might acquire the deep knowledge of these traditions necessary to bring out meaningful performances in our time. Among the more important, I might add more illusive, necessities has been that of the comprehension of the true nature of the organ in the traditional or ideal sense and of the function of organ tone and tonal design in the actual realization of musical values in performance.
It is not our purpose in this discussion today to go deeply to points of tonal design or the actual composition of the organ as required by purely musical considerations, we are rather limiting ourselves to those physical or architectural aspects which influence the over-all aesthetics as perceived by the eye and ear.
We are now more than 30 years into our organ renaissance. Much has been tried and much has been learned. The past ten years has seen the movement in Europe reach a maturity which we in North America have yet to accomplish, but our striving has borne much fruit, and the past few years have brought us to the verge of true appreciation of the essential worth and integrity of the organ as a sensitive musical instrument and as the leading musical instrument of our society for use in the service of divine worship.
We have passed through a period of transition in which these qualities have been apprehended by only a few musicians, clergymen, and organ builders, to the point where the demands of an enlightened laity now require continued aesthetic progress. With a continuing and growing demand for more effective organ installations in our churches assured, we are now entering a period where we may expect to gain ultimate maturity. Therefore it is appropriate that we summarize those points which have been learned from the great masters of organ building of the past and which our more recent experience has proved to be inviolable.
First of all, the organ should be constructed completely within the room which it must serve. A placement in some architectural appendage, anti-room, closet, or attic area can no longer be tolerated. No area which might justifiably be described as an organ “chamber” is acceptable.
The organ should be freestanding on the floor of the nave, the chancel or some elevated floor area such as a gallery or loft. Although the organ cases of some large 17th and 18th century instruments are so extended as to give the impression that the instrument is built in into an alcove or recessed area, a careful investigation will prove that this is seldom the case. Traditionally, the organ stands quite separately from the building as a separate piece of furniture, and the accumulated experience of centuries has found no better way.
The organ should preferably be located on the central axis of the church either in the “west end” of the nave or in the “east end” behind the altar or communion table, or other “worship center” whatever form it may take. Of course, the basic considerations that the choir must be located in a position close to the organ and that the sound of both the choir and the organ must be well distributed throughout the nave, must always prevail. A somewhat elevated position, such as that provided by the typical “west end” gallery or the “east end” choir loft as found in some non-liturgical American churches, is always best. Other locations, such as in transepts, transept galleries, side locations in open chancels or placement in a bay of the nave, can, under ideal conditions, give good results, but from these areas the sound of the choir and organ can seldom be distributed with the same degree of efficiency and uniformity as that afforded by placement on the central axis.
Although the organ is composed of several divisions, these divisions are closely related, and while space differentiation in the sound between the divisions is desirable, the various elements of the instrument should be placed closely together and not distributed about the church. Although a horizontal arrangement in the relationship of the various divisions is permissible where lack of height is a problem, such an arrangement is far from ideal since it tends to create a non-uniform distribution of sound. The traditional and time proven arrangement requires that the instrument be built vertically, and the traditional vertical relationship in which the manual divisions of the organ are placed one above the other with the pedal divided and placed on each side is preferable as it usually provides for an equally effective distribution for the sound of the component divisions while maintaining the desired spatial contrasts.
Within a division of the organ, the stops should be placed according to their traditional relationships with the Principal stop always place at the front “en façade” with the “upper work” and mixtures placed behind.
The instrument should always be encased, preferably with an individual housing for each division. The individual cases not only project and amplify sound but, through the influence of their resonant frequencies, they play a very important part in establishing the individual timbre of the division they surrond and thus serve to heighten the constrasts between divisions. Instruments of the “exposed” type in which all of the pipework is displayed, usually with the upperwork (smallest pipes) toward the listener, have been prevalent in American organ building for more than 25 years, but they have been succesful rarely and this usually in large reverberant buildings where the instrument is a long way from the listener. Even the most successful of these exposed instruments are still lacking in the warmth, the beautifully balanced ensemble, and the clearly cut contrasts between divisions, characteristic of encased instruments, both old and new. Then, also, in spite of the extreme “brilliance” often evidenced in exposed instruments, these instruments seldom really project well and thus frequently lack “presence”. “Presence” is a special characteristic of well designed encased instruments, even when heard from considerable distance. Recent experience clearly indicates that encased instruments are a ways more successful than unencased instruments, whether the acoustics are extremely lively or relatively dry. In lively rooms, more direct sound reaches the ear of the listener when the organ is encased. Thus clarity is retained in spite of the prolonging effect of reverberation. In less lively situations, more sound is distributed by the interior surfaces of these enclosures and there is added warmth and amplification provided by countless short echoes from the walls of the cases combining with the direct sound from the pipes.
The question of the size of an organ for a given situation is one that is constantly with us. By size, of course, we usually mean the number of stops and the number of manual divisions, or, reduced to the simplest possible terms, the number of draw-knobs, or tablets, and the number of keyboards. Unfortunately, there is no standard basis for an answer to this question. However, based on an ideal church situation in which the instrument is ideally placed in an ideal acoustic environment, with a choir of a size proportionate to the seating capacity and with a congregation that sings well, a conservative formula for the number of stops in an organ that in practice has shown rather consistently good results is
one stop for each 30 people,
plus one stop for each 100 people.
Below 500 seats this would give an average of about 4 stops per hundred seats. Since a three manual organ of less than 30 stops is really more limited musically than a two-manual instrument of an equal number of stops, and since it is also economically less advantageous, this approach would mean that a three-manual organ would be considered only for a church with a seating capacity or 700 or more.
Of course, this solution can only apply, as I suggested before, for an ideal case. It would give real satisfaction only where the congregation and the musicians involved have made all the “right” decisions either by choice or by instinct concerning not only the physical aspects of the organ installation and other musical facilities but also with regard to their whole musical program. It is typical of such a situation that all overly ambitious ideas as to the character and magnitude of the music to be performed have given way to a definition of the musical needs which is entirely commensurate with the size of the church and its appropriately proportioned musical resource. This does not mean that the quality of the music or of the performance need in any way be compromised. On the contrary, the result will be a ccompletely uncompromised and worshipful musical offering of exquisite taste.
I certainly do not want to give the impression that any church with an organ not conforming in size with the solution given by this formula has violated some principle of good taste. Certainly churches in the 100 to 300 seat range would find an organ of 14 or 15 stops very satisfactory and probably not overly demanding so far as space requirements are concerned. Increases of one or two, or even four or five, stops in any range possibly even as much a 25 to 30 per cent in the range up to 500 seats could not be considered inappropriate late providing they can be easily and correctly accommodated. In the range above 700 seats, in good acoustics, instruments somewhat smaller than indicated by the formula often serve quite well and, in an absolutely superb situation, a room seating 1,500 might be well served by about 40 stops. However, as I have already said, this formula is really very conservative so far as good church use is concerned and is derived to give good results in accompanying a robustly singing congregation while maintaining a beautifully balanced instrument with a gentle, singing, unforced tone, placed and voiced in a manner entirely consistent with the principles of good organ building practice, as outlined earlier. Organs of the size given by this formula, at least those given for more than 300 seats, will always meet the true musical needs of any church. They will do justice to a more than adequate segment of the organ literature, and they will always be easy to accommodate in a properly proportioned church.
On the other hand, instruments which exceed the size given by the formula by more than 50% can only rarely justified on a basis of need, and then only on a basis of requirements other than those of church use. Such instruments will often require more space than is readily available and may be very difficult, if not impossible, to place in a manner consistent with good practice. Full musical value is not possible from an instrument poorly placed. It is always better from every point of view to have a smaller well placed instrument than to have a larger instrument that is not well placed. The general rule should be to keep the instrument as small as possible consistent with meeting the musical needs of the individual church situation. It should go without saying that basing the size of an organ on considerations of prestige or of status is an anathema.
Although not strict a musical consideration, the organ has traditionally been an architectural element of considerable beauty, and the façade has always reflected the arrangement of the various divisions of the organ. Again, today, the instrument must be considered an important part of the furnishings of the interior of the church - an item of furniture, if you will, such as the pulpit or lectern. Therefore, its visual design must be carefully planned, and where funds permit, it should be a real work of art. Except in Holland, where truly great organ cases were still being built long after the year 1800, the design of organ cases deteriorated rapidly after the early years of the 18th century. Traditionally, the organ builder was always responsible for the building of the case or the renovation or enlargement of a reused case, and one need only study the solution of organ case design at the hands of organ builder Gottfried Silbermann, to know that the decline of the organ case as thing of great functional beauty cannot be exclusively attributed to church architects.
Actually, in the beginning, this decline was merely another manifestation of the evolving tonal decadence of the organ which marked the period of the heightening of romanticism as way of life, and which finally led to the complete downfall of the King of Instruments and the crowning of the symphony orchestra as the chief medium for musical expression. This period, which saw the lushness and sensuousness of “symphonic thinking” eventually permeate the music of the church, also witnessed the design of many meaningless and architecturally abominable organ cases, often from the hands of well-known architects. The eclecticism of Victorianism carried well into our present century. With both the meaning and the beauty gone from the face of the organ, is not difficult to understand the tendency of architects to place organs in chambers, and to cover them with pipeless screens which grew rapidly after 1900. Still, it is this “let's put it behind a screen” approach on the part of many of our architects today, that has retarded the progress of organ “architecture” in America. Now, while I can understand and perhaps even justify the use of screens to hide organs as a logical result of Victorian design of the organ, I cannot believe that any serious-minded architect really believes that a screen provides a legitimate solution to every difficult or un-solved design problem. If the screen is a design tool of such merit, let us not restrict its use to the organ. I know of several recent churches which might be greatly improved if they were completely concealed behind screens.
Unfortunately, no North American architect that I know of is in possession of enough information concerning either the dimensional requirements or the traditional requirements of the functionally designed encased organ to be able to do any work alone along these lines. The essentials of the design must therefore be worked out by an organ builder. However, the design possibilities are virtually limitless within the disciplines posed by the “physics” and musical requirements of the individual situations. It is the disinclination of the architect to accept these disciplines that has caused in him a sense of utter frustration in dealing with organ design. Architects have experienced similar frustration from the disciplines imposed by good acoustical practice, various liturgical practices, structural engineering, and even by the dimensional and comfort requirements of the human body, but experience shows that these frustrations fade with increased familiarity and acceptance of the disciplines involved.
A few years ago, there was hardly an architect anywhere that would allow an unencased, exposed organ in one of his churches. Today, this mode of organ design is rather generally accepted and it is indeed unfortunate that the musical value of this arrangement is so unworthy of the wide acceptance it now enjoys. The misapplication of the term “functional” to the exposed pipe work has no doubt made a considerable contribution to this high degree of popularity, but this expression is most inappropriate since very few exposed instruments really reflect, in any real sense, the musical formation or function of the pipe work or the logic of the tonal design. Actually, when an exposed instrument is arranged in a musically functional manner, the interesting pipe patterns and textures which have, done so much to sell exposure to architects are all missing or hid from view and thus it is much less acceptable visually.
However, encased freestanding instruments can be built that are in all respects musically functional and therefore architecturally functional in their design while at the same time presenting a visual effect as modern as tomorrow, if required to do so. The one element in an organ that stubbornly refuses to yield to visual design concepts is the organ pipe itself. Except for the possibility of slight design alterations in the shaping of the lips of façade pipes, the organ pipe is a purely functional device, its geometry being determined by physical laws which have defied designers for more than 500 years. The long standing traditions concerning the size and a shape, hence the appearance, of organ pipes often excite cries of “old-fashioned” from contemporary church architects, but if organ pipes are old-fashioned and therefore unworthy of a place in churches of today, then so so also is every traditional geometrical element. How do we “modernize” the circle and the straight line?
Once the architect has accepted the challenge of the organ as a visual presence in the church, although I cannot speak for my colleagues in the field, I can assure him that he will find this particular organ builder most willing, indeed eager to cooperate, in bringing to being, not only a fine musical instrument, but a beautiful visual element within the church. In any organ building program, the only valid motive must be to produce as effective an instrument as possible within a given set of circumstances. Perfection cannot be gained by compromising with basic principles, whether these are principles of organ building, acoustics, visual aesthetics, or of worship. We have all had far too much experience with compromising our ideals in so called “cooperative” efforts. It is now time that we gained a little experience in cooperative non-compromising in a concerted effort to answer the real and enduring need of the church community. In our constant striving toward perfection which is in truth our reason for being, we must maintain the flexibility of approach that will give us the freedom needed to cope with varying circumstances, but our standards of performance must not be flexible or variable in any phase of our work or we will soon lose sight of our goal, a clear view of which must always be before us if our endeavors are to be crowned with success.