The Aulos Ensemble will take listeners on a trip back in time tonight when it brings Baroque music and instruments to Schwab Auditorium.

The ensemble will play music from three well-known Baroque composers -- J.S. Bach, George Friederich Handel and Antonio Vivaldi.

The Baroque style of music was popular in Europe from about 1600 to 1750. Many musical concepts and instruments were developed during this era.

"This is great music, played with a lot of energy, finesse and commitment," Penn State School of Music double bass professor Robert Nairn said.

Nairn will perform with the Aulos Ensemble, although he is not a regular member. He first became involved with the group because of the Handel and Haydn Society of Boston, in which most of the Aulos musicians also participate. The Society, like Aulos, performs classical music on original instruments.

"The instruments [of the Baroque era] themselves are in most cases very different from those in use later in time," Marica Tacconi, associate professor of musicology, said.

However, Aulos didn't always use original instruments of the era.

"When we started we played 'modern instruments' although we played mostly baroque music," Marc Schachman, Aulos oboe musician, said. "We changed to 'old' instruments in 1975."

Schachman said the baroque instruments have a "softer and mellower" sound than today's instruments that evolved from them.

"The sound of baroque instruments is a very intimate sound, in keeping with the settings and situations that composers and performers found themselves in during the 18th century," Schachman said.

Nairn said Aulos' use of restored instruments from the historical period creates a lighter and richer sound and provides a fuller tone. He also said the instruments aren't the only reason the group sounds the way it does today.

"Period performance is not just a historical re-enactment," Nairn said. "It begins with a study of the historical literature, then has a lot to do with spending many years performing on the instruments, learning instinctively what works and what doesn't."

The Aulos ensemble was formed in the 1970s while the members were students at Julliard. Today, they tour often and have created their own concert series in New York City. They also perform an annual Christmas concert in the Medieval Sculpture Court at the Metropolitan Museum of Art.

"I helped form the group as an outgrowth of the various activities in chamber music and baroque performance," Schachman said.

Nairn said people rarely get the chance to hear a small Baroque ensemble of this caliber.

"For people who have never heard these instruments, it will be an interesting thing to discover, and the music that we're playing is some of the greatest music of the early 18th century," Schachman said.