Acoustics for theaters: Acoustic principle and order of the orchestra

Hi guys, these last months I've been studying a lot about the acoustic principle of theaters and concert halls as part of a subject of my career, and I've fallen in love a bit with the acoustic logic of the concert halls for orchestras, since it's something that not only the acoustic work of the room matters, but also the distribution and order of the instruments, the amount and strength with which they perform according to the arrangement presented by the composer.

I would like to start by explaining a bit about how these places are designed and because without the need to use microphones the sound of the instruments in the room is amplified in a uniform way, something that was very interesting for me, but there was little information about it.

The main idea in these places is to use acoustic amplification, the orchestra is inside a kind of dome that will increase 3dB of sound pressure (dB SPL) for each wall or surface that surrounds the sound source and eject everything by the only means of exit of the sound impulse, that is to say that having a floor, a roof, a back wall and 2 side walls we increase 15 dB to the natural volume that the orchestra exerts, this will allow the orchestra to sound with more force and go further without loss of volume by distance.

Another of more things that allows the volume mix between instruments is the distribution of them throughout the length and width of the stage, this way they can have depth and amplitude in the mix depending on the instruments that are used.

The order of the instruments has much to do with the principle of acoustic amplitude, in this way you can see instruments of great amplitude at the same volume as instruments of very low acoustic amplitude.

As can be seen in the image, delicate or subtle instruments such as violins and other strings go to the front, and those of greater amplitude such as percussion instruments and metals are at the bottom, thus leveling the volume of them, in addition They have the intentions or nuances to level volume.

The intentions or nuances, as some call it, are nothing more than the force with which the instrument is going to be played, this generates a sensation, a presence and a different timbre depending on the intention with which it is being executed.

Many composers also use this as a means to give space to specific instruments, to create an environment or to create prominence. These nuances are known as piano, pianissimo, mezzo piano, mezzo forte, forte, fortissimo, forte piano.

The musical scores are full of intentions for these reasons, although currently it is used more for an artistic theme of generating environments or intentions, in the past it was more used so that the instruments could be understood individually in an acoustic enclosure, since these they were not logically made for acoustic amplification.

The architecture has advanced at very important levels in terms of the construction of acoustic enclosures for concerts, theaters and auditoriums, it is increasingly mixed with sound engineering to perfect this, the clearest evidence of this is the 360 ​​theater of Circus Soleil in las vegas, which works both with acoustic conditioning, and with a surround system that allows the audience to hear the same at any point in the room.

Here I say goodbye guys, I hope this seems interesting, I will study more about this to see what new things I can bring on the subject, there is much to investigate and discover, and even other themes of music that we do not know.