STEPHEN BAIRD, executive director of Community Arts Advocates, protests new restrictions on street performers. The MBTA regulations, with dress codes and banned instruments, will take effect on Dec. 1.

When Stephen Baird tries to communicate something important, his voice drops to a tremulous murmur and his eyebrows bounce excitedly above the rims of his glasses. Yesterday, his eyebrows danced so vigorously they could have been trying to make music.

Leaning into the microphone in a bar crowded with street musicians yesterday, Baird, executive director of the Community Arts Advocates, railed against a new policy that will prevent many of them from claiming their subway-station stages.

“Some people will become homeless because of this issue,” Baird told the assembled crowd, his white beard and flowing hair standing out against the red walls of the Middle East cafe in Central Square. “Others will just be silenced.”

The target of Baird’s ire was the MBTA Subway Performers program, which, as of Dec. 1, bans amplified performances and several acoustic instruments, imposes a dress code for performers, and establishes 25 other counts of MBTA authority over the musicians. Many street musicians, like Baird, consider this an assault to their professional lives and their personal freedoms.

“I can’t wrap my head around this,” street performer Brian James shouts over the crowd at the organizational meeting of Boston area street performers opposed to the changes. “This is such a part of the fabric of Boston life.”

Markus Nechay, a self-described “jack of all sounds,” who used to perform flute in the subway, came to Boston as a street musician from New York City.

“At first, I thought it was kind of a loser town,” he explains. His exposure to musicians in Harvard Square convinced him otherwise, he said—and made the transition to an unknown environment easier. “It provided a lot of relief for the stress of being in a new city.”

The subway musician Michael Sullivan voices similar sensibilities. “It’s a privilege for the MBTA to have us there, and it’s a right for us to be there,” he cries, turning the conventional phrase on end. The crowd cheers.

A Fight for Sound

Boston’s community of street musicians is an intimate one. Milo Matthews, a veteran bassist at Harvard and Davis Squares who recently extended his performance circuit to South Station, cracks several smiles of recognition as his eyes wander around the room. He says he knows most of the meeting’s other guests.

Squeezing into murkily lit booths at the Middle East bar, which an employee had donated to the cause, the group could be posing for an overcrowded Van Gogh canvas. Baird fusses with poster boards containing his hand-written agenda before taking the microphone.

“Our task ahead is quite substantial,” he says, drawing out the syllables ominously. Though frequently lamenting the brevity of the meeting—the first to be held since the proposal went public Nov. 12—Baird, who has been an advocate of street musicians since he and his audience were arrested during a 1979 performance on Boston Common, sets aside a few minutes for the guests to identify themselves.

Some are veterans of the profession, recounting careers spanning tens of years and several cities. For others, street performing offers an escape from other professions.

A young man who calls himself Fish the Magish spends part of his week working as a paralegal aide. “Then I go out and street perform, because it’s a passion,” he says. By the end of the meeting, the curbside musician is helping to coordinate the creation of a legal brief for their cause.

Several of the meeting’s attendees are simply fans.