US1737666A

US1737666A - Auditorium

Info

Publication number: US1737666A
Application number: US55044A
Authority: US
Inventors: Milkutat Ernst
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-04-08
Filing date: 1925-09-08
Publication date: 1929-12-03
Anticipated expiration: 1946-12-03

Description

1 1 E. MILKUTAT 1,737,666

AUDITORIUM Filed Sept. 8; 1925 5 Sheets-Sheet l Dec. 3, 1929.-

E. MILKUTAT AUDITORIUM Filed Sept. v 1925 5 Sheets-Sheet 2 Fig.8.

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E. MILKUTAT AUDITORIUM Filed Sept. 8, 1925 5 Sheets-Sheet 5 Fig.13.

Patented Dec. 3, 1929 PATENT OFFICE ERNST MILKUTAT, 0F TILSIT, GERMANY:

AUDITORIUM Application filed September 8, 1925, Serial No. 55,044, and in Germany April 8, 1925.

My invention relates to a method of constructing rooms to insure good acoustic effects, and it is an object of my invention to so construct rooms for concerts, theatrical and other performances, lectures, etc., that the sounds produced are heard to full effect.

To this end, I proportion such rooms to the golden rule of proportion and construct them with a ceiling of hyperboloid shape.

It is well known that musical and other performances, lectures and the like, are often much impaired by bad acoustic conditions, by deadening of sounds, resounding, etc. The attempts made heretofore to improve such poor conditions were more or less of a tentative character, though based on the experience of years.

These drawbacks are overcome by my invention which enables the effect of sound to be increased and opens up quite new prospects-in the architecture of rooms of the kind described.

It establishes a new rule by which rooms having good acoustic conditions may be constructed regardless of size. It shows the connection of cause and effect and so enables not only new rooms to be designed on these principles but also enables existing ones to be tested for their acoustic properties.

Obviously, conditions which bring about a more rapid reflection of sound and eliminate resounding, for instance, polished wainscotting, will favorably influence the acoustic conditions of a room, but such details are secondary to the fundamental principle of proportion aslaid down by my invention.

In the drawings, the application of my novel method is illustrated by way of example.

Fig. 1 is a diagram of the golden rule of proportion or golden section.

Figs. 2 to 8 are diagrams showing the paths of sound waves in parallel toa wall,

Fig. .9 is a diagram showing the influence of a disturbing element in the path of the waves,

Figs. 10 and 11 illustrate the arching of the ceiling of a room constructed in accordance with my invention,

Fig. 12 is a plan view of a concert room in accordance with my invention, with a room for the band,

Fig. 13 shows the path of the sound waves as it will be under the influence of the arch in Fig. 10.

Referring now to Fig. 1, the line a will be divided on the golden rule of proportion if the larger section b is the geometric mean of the entire line a and the other section (a-b).

To effect such division graphically, erect a vertical on the line a-in one of its end points, B, make this vertical BC equal to one half I the line a, draw a circle about C with the radius CB, connect A and C and draw another circle about A with a radius equal to the distance from A to the point of intersection with the first circle of the line AC, this point being indicated by D. The intersection of the circle AD with the line a, G, is the point of division on the golden section.

Now, b is to (ab) as a is to Z), or, expressed as an equation,

he length of the larger section is and the length of the shorter section is These equations are established as follows:

By forming the quadratic completion to the equation b +aba =0, the following is obtained:

and, by adding both sides of the equation, the result will be by multiplying with 4 from which extracting g,

If constructing a room from these data, so that a is its length, b is its width, and (a-b) is its height, it will be found that its acoustic conditions are very good.

This is based on several causes the most important of which is the very regular distribution of the waves or systems of Waves in space so that throughout the room and even in its smallest part the frequencies and intensities of the sound are substantially equal and no particular type of sound is accumulated or separated anywhere in said room. Another cause is the fact that a system of waves emitted from any point of the room in any direction, is, after comparatively few reflections, as compared with other rooms, directed into the corners of the room or returned to the origin, the sound emitting body.

Figs. 2 and 3 illustrate wave systems extending in parallel to the walls and having a reflection angle of 45 degrees. The cause I is the continuous reflection of the waves by the walls because said walls are in a steady constant ratio to each other.

As the proportion is a constant one, the same law also applies when the wall has the length a and the width (a-b) or 2ba.

Figs. 4 and 5 illustrate systems of waves extending in parallel to the walls for the first case in which the length is a and the width (ab). Figs. 6, 7 and 8 show that this applies to any angle of reflection.

A disturbing body in the way of the waves does not destroy this acoustic behavior. On the contrary, it will often even reduce the length of the wave routes, as shown in Fig. 9.

Considering now the routes of the waves, for instance, in Figs. 4 and 5, as projections of the wave routes on the walls of the resonator, the same will apply to the route as to its projection.

Another cause of the good acoustic conditions is that with superimposition of waves for the same sound, amplitudes of equal, viz, double, and therefore, maximum length are formed, which are uniformly decreased by reflection. The resulting energy I from the two interfering oscillations is equal to four times the single energy, if the energies of the interfering oscillations are equal, because the energy is pr iportional to the square of the amplitude. his also applies to overtones.

Such a room has a high sound capacity even for very high sounds emitting short waves.

To prevent the reflection coeflicient in the resonator from becoming too hi h, it is possible to reduce said coeflicient %y a special construction of the ceiling, that is, intensifying the sound. This requires arching of the ceiling of the resonator. A ceiling constructed in accordance with my invention is shown in Figs. 10 and 11 Fig. 10 is a cross section of the room. The hyperboloid arch is constructed by suitable means, for instance, from evolvents, by dividing the height of the room into two halves and dividing the upper half into n equal parts.

Similarly, the length of the ceiling is divided into halves, each half being subdivided into n equal parts.

Said verticals are erected on the points where the lines are tangent to the curve. In this manner, a hyperbola is obtained, 0 being the factor of proportionality. This hyperbola can be used from b =%y 2112b, to m =a d yn 5 Or,1fa

' b 10, 37 :1 l :1 to d ab 2ba a b I a-b but also the indirectly steady relation of and and so on.

Fig. 13 shows the route of the waves under the influence of the arch in Fig. 10. The principle of steadiness of wall lengths applies to all rooms including those that have more than six plane walls.

As an example of a room with band stand, Fig. 12 is given. Here, a is the length, l) the width, (ab) the height of the room. The length of the band stand (or' stage) is (a 6), its width being (2ba), and being shaped iike Fig. 10 in plan View.

In a specific case; given the length of the hall or room, for example 100 feet, the other dimensions of the hall could be computed as follows: i

The arm A0 of the triangle, see Fig. 1 being 100, and the arm B0 being %or 50, the hypotenuse A0 would be 111.8+. The distance AD would be A0DU=AU 0B=111.8+ 50=61.8+. The line AD being the same length as AG, the distance Z) 61.8+. The distance GB a b 100 61.8 38.2. The dimensions of the room then are: length 100 feet, width 618+ and maximum height 38.2-. In the same manner lb-a 1236+ 100=23.6+, etc. It will be seen that these dimensions 100, 61.8+38.2 and 235+ bear a constant relation to each other. It will be obvious that the dimensions of any size room can be computed by this method.

I claim:

1. An improved concert hall or the like which consists in a room the numerical values of the dimensions of the length, breadth and maximum height of which form a mathematical series formed according to the golden rule of proportion, which comprises a series in which each term is the mean proportional of the terms which precede and follow it respectively and in which the ceiling of the room is hyperboloidal in form to avoid obliterations of sound.

2. An improved concert hall or the like which consists in a hall the numerical values of the dimensions of the length, breadth and maximum height of which form a mathematical series formed according tothe golden rule of proportion, which comprises a series in which each term is the mean proportional of the terms which precede and follow it respectively.

3. An improved concert hall or the like which consists in a room the numerical values of the dimensions of the length, breadth and maximum height of which form a mathematical series in which each term is the mean proportional of the terms which immediately precede and follow it respectively and in which the ceiling of the room is formed according to two hyperbolae the asymptotes of which intersect on a line passing vertically through the center of the ceiling and the limbs of said hyperbolae meeting at one end of the center of the ceiling and at the other end joining with walls parallelly disposed so as to maintain the symmetry of the shape of the room.

4. An improved concert hall or the like which consists in a room the numerical values of the dimensions of the length, breadth and maximum height of which form a mathematical series in which each term is the mean proportional of the terms which immediately precede and follow it respectively and in which the ceiling of the room is formed according to two hyperbolee the asymptotes of which intersect on a line passing vertically through the center of the ceiling and the limbs of said hyperbolae meeting at one end at the center of the ceiling and at the other end joining with walls parallelly disposed so as to maintain the symmetry of the shape of the room, there being an orchestra space built on to the concert hall proper having the shape and dimension ratio of the large hall while the hyberbolic interior formation is used on the side of the orchestra space facing towards the concert hall.

In testimony whereof, I have signed my name to this specification.

ERNST MILKUTAT.