Mr. Fisher explained that they were all, in effect, testing City Center's new acoustical shell erected around the back of the stage.

And he campaigned for an acoustical shell that has greatly improved the sound at the academy.

In addition, the renovation project completed an upgrade of the Symphony Hall stage and constructed a new acoustical shell.

On either side of the stage are acoustical shells for an orchestra and choral groups.

Mr. Toyota, he said, had insisted on an acoustical shell for orchestra concerts so massive that it acts like a permanent structure.

The old heavy acoustical shell kept falling through the floor.

A customized acoustical shell was added to Reynolds Auditorium in 2009.

The thing that is most apt to drive orchestral musicians up an acoustical shell is mindless repetition without constructive criticism.

In later years, the orchestra used a special acoustical shell that was placed around the musicians, greatly enhancing acoustics for concerts.

An acoustical shell and a state-of-the-art lighting system assisted the Coliseum in presenting such activities.