# Concert Halls as Nearly Adaptive Spaces
## 4 The Case Study
### The Adaptive Concert Hall as an Active Musical Instrument  
The auditorium of the \"Nuovo Teatro dell'Opera\" in Florence is an adaptive concert hall in which the acoustic response can vary rapidly during the execution of a piece of music, without introducing noise; the RT changes seamlessly, and the referred values are known in real time. This means that the concert hall can play an active rule during a music performance without being supported by electroacoustic equipment. The RT can be reduced from a high value, which falls in the optimal acoustic range for concert halls, to a target that usually refers to speech auditoria and vice versa. These characteristics make an adaptive concert hall different from a multipurpose room, in which variable acoustic movements usually increase the background noise at unwanted levels and, in most cases, RT variations are slow and refer only to preset configurations. In the case study, the curtain movement speed, which changes the reverberation time, is controlled by the DT to ensure that the composer's requests are met as well as to allow for simulations to evaluate the values of RT in real time. For musical instruments which are not electrically amplified, the sound pressure level in the space is determined by type and number of musical instruments playing at the same time, the style of playing, and the dynamic expression, while the audience's perception of the sound pressure level changes, especially according to the reverberation time of the hall. If the reverberation time is too long, the sound becomes thick and unclear. However, if the reverberation time is too short, the music becomes dry, and the tones lose some of their timbre and brilliance. This is most significant for vocals, woodwind instruments, and brass instruments, while it is less of a problem for piano and string instruments, which have a built-in sound board. If the hall is not active, i.e., if it is a passive one, musical instruments can be played at different sound powers during a concert while the reverberation time remains constant for the entire execution of the piece, especially if the concert is not amplified with electroacoustic equipment. In an orchestra score, the most common instrument dynamic designations for different sound power are indicated. They are pianissimo-piano-mezzoforte-forte-fortissimo (pp-p-mf-f-f). Pianissimo specifies that the sound is very quiet but still with timbre; fortissimo  
Figure 11: Single seat diffuser and heat load definition by volumetric heat source. is very loud, but without the timbre being distorted. There are also ppp (extremely quiet) and fff (extremely loud). The dynamic range from pp to ff for solo musical instruments is typically around 25 dB(A) to 30 dB(A), somewhat less for the flute and the oboe, and somewhat more for the clarinet and the horn. An orchestra may have a dynamic range between 50 dB and 60 dB. This dynamic range also depends on the musician's proficiency. In analogy with the dynamics of musical instruments, a new designation is proposed for the reverberation of an active concert hall to be included in the score, as discussed with composers of the Santa Cecilia School in Rome. The highest reverberation time condition, the target suggested by the literature for concert halls, is indicated with RR, and it usually refers to the highest possible reverberation time of the hall. In the case study (with the agreement of the composer who will be commissioned to write a new piece that includes the active room response), when the RT is reduced seamlessly achieving the measured value for 50% curtain deployment, the reverberation time is identified as mR and the RT equal to the last measured configuration 100% curtain deployment is indicated as DD.