The need was apparent after Byrd Ensemble's performance of Handel's Dixit Dominus with the Seattle Baroque Orchestra in March. The detail was lost in the room and the singers had to compensate by singing their heads off. It was a little disappointing, especially because St. Mark's is a fantastic venue in other ways. It has that mystical, otherworldly aura that complements our music so well. Oh, and it has PARKING.
Now that we are an artist-in-residence at St. Mark's Cathedral, we were determined to improve the sound for our upcoming concert season. We first looked into renting a shell. No luck. Apparently people are very protective over their precious acoustic shells. I suppose I would be too at a cool $7,000 a piece from the Wenger Corporation. No thank you, and, your shells are ugly.
TAP Plastics who were incredibly helpful in suggesting and providing samples of plastic we could test.
We wanted to test the reflectivity of each plastic sample so we designed an experiment that involves using a sound source (in this case a wireless Bose stereo system), a sheet of plastic to test, and a mic to record the sound reflecting off the plastic. First, we cut the plastic samples using a miter saw so they were all the same size.
Then we lined the box up with padding to be as sound absorbent as possible.
[The audio we played through the Bose speaker was a chord built from sine waves, free of overtones. We wanted to isolate frequencies closest to the chord so we moved them to the top of the sheet, in the grey boxes rows 2-15. Columns B - H shows the difference in decibel volume between the control recording and the various recordings using the sample materials. Column R averages all of the grey differences for each material.]
The next step was to design legs that could support the 1/4" 4' x 8' sheet of acrylic, weighing around 50lbs. Each leg is composed of 2 pieces of wood attached by 4 L brackets.
|Legs beta version|
We wanted the shell to be as subtle as possible so we painted the legs black.
Overall we are really pleased with the shell. It cost about $1,100 in materials for 5 panels. We had our first rehearsal with the shell at St. Mark's and I believe it makes an incredible difference. Come check out the Byrd Ensemble's upcoming concert this Saturday, October 4th at St. Mark's Cathedral. I'd be really interested in what you think!