“Less than 5 percent of women are creating and shaping the sounds and media that make the constant soundtrack of our lives," Winston says. "So the perspectives of women and girls are barely audible. They need to be amplified in order for our girls to thrive."

I met Winston the following day at the WAM studio in San Francisco's SoMa neighborhood. She helped me bring my bike into the garage and walked me through the soundproofed labyrinth of studios and classrooms. In a room where an audiobook was about to be recorded, a woman sat comfortably behind a mixing console with hundreds of knobs and levers. It resembled the control panel of a spaceship in a sci-fi movie.

Winston founded WAM over 13 years ago. While teaching in the Broadcasting Department at City College of San Francisco, she was disappointed by the lack of women in her class, so she founded an audio club for women.

That year, Winston booked a booth for her club at a convention for the Audio Engineering Society, the largest professional association of audio engineers in the country. According to an AES representative speaking to Huffington Post, less than seven percent of AES members are women. Winston tells me that the conventions are overwhelmingly white and male. “They even dress the same,” she says.

At first she was met with suspicion -- organizers thought she was planning to protest the convention. But her booth was a huge success. Winston received armfuls of donated equipment from manufacturers, so much that she had to find a shopping cart to wheel it all around.

“That’s how WAM started, in a shopping cart,” says Winston.

AES has given WAM a booth every year since.

At City College, Terri’s classes reached parity with men and women attending. It didn’t go unnoticed. People began coming to Winston asking how she was able to get women interested. Instead of traveling to share her success, Winston decided to build a studio “to put all those best practices in one place” and created WAM.

These days, WAM trains 1,200 women every year. Of those, 850 are middle-school girls. Also, 93 percent of the girls are low-income, 83 percent are girls of color and 73 percent don’t have access to a computer.

Winston says she is targeting young women with some of highest dropout rates in the state of California. “We are serving the lowest-income students on purpose,” she said.

Winston says a lot of her students start out believing the nerdy male engineer stereotype. Her classes combat this by not giving anything a label while the girls are learning.

“We don’t push referring to this stuff as STEM. We know what we are doing on our end. Until those words get detached from certain stereotypes you’re not going to see girls doing it,” Winston says. “Ironically, after 18 weeks of training, they get to work on a project where they are assigned various music production roles. They usually fight over who gets to be the engineer.”

While WAM works to fix the pipeline of women studying audio engineering, many men skip the pipeline altogether. Audio engineering has a tradition of mentorship, and because most mentors are men, it becomes less likely for women to be brought into the fold.

Claire Boucher, also known as Grimes, spoke to NPR about the gendered stereotypes in song production, with men producing beats and women singing melodies. “I wasn't allowed to touch a computer, for example, even though guys in the studio were allowed to," Boucher told NPR. "I obviously know how to use a computer and I know how to produce, but I had to tell the engineer what to do if I wanted to do anything, which I thought was pretty crazy in the 21st century."

“I came in with experience as a producer and I wasn't allowed to produce -- so how could any woman who didn't have experience as a producer ever learn how to produce? It was just a little odd in that regard," Boucher added. "If there are stereotypes of, ‘Women do certain jobs in music and men do certain jobs,’ the way the studio works, it's not easy to escape that."

“We have to be twice as good as our male counterparts to be considered on the same level," says Julie Indelicato, a San Francisco-based sound engineer. "Some bands will even apologize to the audience for the fact that I’m a woman.”

Indelicato has worked the soundboard at live shows in the Bay Area for eight years. “I often have people coming up to me asking if I need help,” Indelicato says. “It happens every time. Even by laypeople. You wouldn’t ask a plumber if they need help fixing your toilet.”

She says it’s a common experience for bands to walk right past her in the sound booth and ask the nearest man where the sound engineer is. “These days I walk towards them before they can overlook the fact that I’m working there,” she adds.

"I’m an African American lesbian woman working as a sound engineer. This is a mostly white male industry," Indelicato tells me.

On top of being dismissed, women work in a world rife with sexual innuendo and misogynistic comments. “It’s a bawdy environment. There are lots of sexual jokes and complaining about girlfriends and wives,” says Indelicato.

When I ask Indelicato why she thinks it’s like this, she tells me, “This is 1099 work. We are mostly independent contractors. The only person who will stand up for you is you. It’s so hard for women to speak up for themselves when they are already being questioned the moment they walk in the door.”

“The audio industry is kind of like the wild west,” Winston says. “You see that it’s really unregulated. You don’t have a human resources department. Nobody is talking about what are appropriate conversations. There is a lot of wild and crazy behavior in studio spaces."