07 December 2011

Computer modeling of Renaissance acoustics


From a presentation at the Acoustical Society of America investigating the acoustics of the Basilica of San Marco and Palladio’s Redentore:
[H]istorians have raised many questions about this period: how could complex polyphonic music be heard in these huge, reverberant churches... modern acoustic measurements show the Redentore to be highly unsuitable for fast-tempo, polyphonic music. The church’s reverberation time – the time it takes for a sound to decay to inaudibility – is greater than 7 seconds. This reverberation blurs fast music, reducing its clarity and intelligibility...

...the monks who lived there would have sung simpler monophonic chants. On the day of the festival, however, the church would have been completely filled with people, tapestries, and temporary wooden seating in the chancel. By consulting with architectural historians, we were able to estimate the absorptive properties of these materials and audience members... Using our acoustic model, we can predict the time and intensity of nearly all the sound reflections in the Redentore...
Modern acoustic measurements have shown that sound sources in the pergoli have an excellent blend of resonance and clarity at the position corresponding to the Doge’s throne. Even in the empty church, the Doge’s position has a reverberation time of 4 seconds, while listeners in the nave experience a reverberation time of nearly 7 seconds...

Like the Redentore, San Marco was filled with people and decorations for festive occasions and holidays. Using paintings of the festal chancel, the computer model was able to simulate the effect of this change, again increasing clarity but reducing overall loudness. The model predicts that the reverberation time at the Doge’s position in the festal church would have been between 1.5 and 2 seconds, which is the desired range for modern concert halls today!  ..

In San Marco, a geometrical analysis shows that Sansovino’s extended galleries were essential to the favorable musical acoustics at the Doge’s throne. This evidence supports the conclusion that Sansovino constructed the pergoli for the purpose of enhancing the split-choirmusic for his employer, the Doge. Even in the Renaissance, it took money and power to get a really top-notch sound system.
More details at the link, where you can also listen to audio simulations of empty and filled "festal" spaces, and compare them with anechoic recordings.

Via CBS News.

2 comments:

  1. Actually, as a choral singer, I had been wondering about just that sort of thing, especially after having been in some of the churches on a tour of Italy (including San Marco). Thanks!

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  2. What?! You mean people could actually figure things out before computers and fancy recording/analysis equipment? That's just crazy talk....

    Sorry. It just drives me crazy to read articles implying that we should be amazed by this type of thing. Hundreds of years ago, people managed to build soaring cathedrals of stone, wood and glass that stand to this day, without using so much as a slide rule.

    Often the only tools the builder (what we would today call an architect or engineer) had were a set of wooden patterns similar to French curves, some pre-measured cords to determine proportions, and his own brilliant imagination and vision.

    The perfection of the acoustical properties were no doubt the fruit of hundreds of years of careful listening, observation, trial and error and - one element sorely lacking in today's society - patience. Such knowledge would then be passed on from one generation to the next.

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