(picture lovingly donated by the Fairbanks Summer Arts Festival)

Above we have the lovely Davis concert hall. This hall is used as an example of acoustics at work in a concert hall.

At first glance one can note the concave reflector at the top, although for some reason it is broken up at various points for lights to hang down from. There is enough surface area up there, however, that the reflector works in reflecting most of the sound sent from the stage. Also note the walls behind the stage - they are recessed squares, each containing a V-shaped backing. Interestingly the walls alternate by either having a convex or a concave backing. Assumedly this is for maximum diffusion of sounds so that no one position in the theatre is the focal point of reflected sound. The walls of the theatre, although you cannot see them, are designed mainly to dissipate sound - the walls are made of sound absorbant material comparable to carpet.

It is the opinion of the author that this hall was designed with fashion in mind more than pure acoustics. Were the author to revise the theatre, he would improve the reflector at the top of the theatre by decreasing the gaps provided for lights. He would then angle the walls of the theatre (those walls not visible in the picture) to diffuse the sound rather than absorb it - he would most likely use sound-reflecting materials with a high coefficient of absorption, as he doesn't want all the sound reflected back at the audience. He would also angle these diffusional wall down slightly, that the reflected sound is not reflected up into the ceiling where there is no reflector and no audience. These are the revisions of a physics 211x student.

Now, to design our own concert hall.

We have chosen the original Greek design of a stage surrounded in a semi-circle by the audience. Since this hall will be used primarily to host speeches by politico revolutionairies and the author's beer bottle quartet, a large stage is not needed. And since we will have a rather large audience at each concert, we will need quite a bit of sound reflected to the back. We have chosen a semi-circular backdrop behind the performers, angled in such a way that it will diffuse the soundwaves.

At right we have the performers on the stage. Sound waves will travel directly from performer to listener, but the clanging of the sticks upon bottles will also travel into the shell and be reflected and diffused in the direction of the audience. We use a diffusionary wall design in order to minimize any 'sweet spots' in the theatre, rather, the entire theatre is the sweet spot.
At left we have our theatre design, note the angled ceiling in order to provide the rear audience with the most sound possible. The audience near the stage is receiving plenty of noise already. The walls of this hall will be designed to have a rather low reverberation time, as the percussive beer bottle group's sound will not be enhanced by a long reverberation, nor will speech. Thus the walls will be constructed of a material with a rather high absorbacy coefficient (0.40) and will be angled to diffuse the sound evenly throughout the theatre.

The colour scheme of this theatre will be lime green and hot pink, designed to have the audience close their eyes to avoid the terrible visuals. This will increase their reliance upon their ears and overall will produce an even more intense sonic experience.

Now, onto the dance club...

(ow! Too long of a reverberation time for dance music!)
(http://www.partyvibe.com/picture_galleries/ravingmad/)

Creating a good dance club is quite different from the concert hall.
As before we wanted an even distribution of sound, but we do not have the good fortune of being able to have a sloped floor (without the dancers falling on their behinds). Much of what goes into creating a most excellent dancefloor is up to the sound engineer, who decides what speakers go where. Yet, an architect can do what he can to make life easiest for the engineer.

With many concert halls, a long reverberation time is preferred, as it enhances the sound of the orchestra - in this setting, we want a rather low reverberation time - no more than 1.2 seconds. Thus we will put heavy curtains on the walls to absorb as much of the sound as possible. The ceiling will also be absorbant - we will hang a sound diffracting mesh from the ceiling, and the real ceiling will be a highly absorbant foam core. We use the mesh as a first level diffuser, but for the most part we are doing it for aesthetics, and also to provide a solid base for the light guys to do their thing.

The room will be something of a parallelogram, and we need not worry about the stage for the speakers placed throughout the room will be making the sound, not the dj. The dancefloor we need not worry about either, for it will be covered with people and they absorb most of the sound before it hits the floor. For their comfort it is suggested that a thick wood floor is used, or perhaps a very very light carpet? We will consult a dance expert.

After that it's up to the sound engineer to make our club come to life.


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