The Concert Companion consists of an off-the-shelf personal digital assistant modified with custom-designed software. During a concert, it displays appropriate commentary—about the thematic development of a work, for instance—prompted by radio signals from a backstage laptop computer.

The Companion has previously been tested at performances of the Philadelphia Orchetra, New York Philharmonic, and Pittsburgh Symphony. According to Valliere, concergoers were overwhelmingly positive about the tests: 93 percent said they would use the device again, and 60 percent said it would make them more likely to attend concerts.

But some musicians and other classical-music veterans consider it yet another intrusion into the concert hall.

"I think the real effect of this thing is to keep people from listening by distracting them by giving them stuff to read, and also by giving them a gadget to fiddle with," Michael Steinberg, a former program annotator for the San Francisco Symphony and New York Philharmonic, told the Chronicle.