Come June 21, as you walk down Broadway, you’ll be wondering, what’s that sound? Down the stone steps of The Shedd, the summer wind will carry the all-women vocals of SheSings 2013 — the Women’s A Capella Festival, with concerts, workshops and a whole lotta musicians.

SheSings is the brainchild of WACA (Women’s A Capella Association) founders Evynne Hollens and Lisa Forkish. Hollens and Forkish were both instrumental in the origins of Divisi, the UO’s women’s a capella group. From their school days, Hollens has gone on to sing, act and direct, and she recently started Synergy, a high school girls’ a capella group that made it all the way to the International Championship of High School A Cappella Finals in New York City. Forkish now teaches at Oakland School for the Arts and led her group, Vocal Rush, to winning appearances in the International Championship of High School A Cappella Finals in 2012 and 2013.

So, these ladies, as the cool kids say, are totally beast.

“When Lisa Forkish and I both moved on from our time singing with Divisi,” Hollens says, “we talked about the idea many times -— firstly, the creation of a Women’s A Cappella Association, and then later a festival. Now, in just a short time, we have created both!”

According WACA, the goal of SheSings is “to educate and inspire, and to create a forum of open discussion, mutual respect and unwavering support for current and future women in a cappella.” For the spectator, the festival will host two concerts. Friday night’s showcase will include some of the best high school and collegiate groups from around the country. Saturday night’s concert will feature Musae, an a capella group of rockin’ women made up of the very best in the business, and Julia Easterlin, a brilliant pioneer who uses looping hardware to create live one-woman choir performances (see her fantastic TEDxWomen performance at wkly.ws/1hy).

“My most simple hope for the festival is that people attend,” Hollens says, “because I know that once we get people in the door, they are going to be blown away, not only by the talent of our performers and clinicians, but by the sheer beauty, uniqueness and power of the human voice, even more specifically, in this case, the female voice.”

For the vocalist, SheSings offers a number of workshops, including Organic Group Arranging and Essential Listening. Instructors will be arriving from all over the country in what will be an extraordinary chance to mingle with the best of the a capella world.

I asked recent high school graduate Esther Ranjbar what this experience means to her. She notes, “Being surrounded by women who all have a passion for music provides a strong support network. I have not always been comfortable with my solo singing voice, but being in Synergy and surrounded by girls who all support each other’s musicality gave me the confidence to branch out.”

Ranjbar is also having trouble choosing which workshops to check out. “I’m not lying when I say I want to attend all of them! One that particularly caught my eye was the ‘Art of Live Looping’ workshop led by Julia Easterlin,” she says.

Hollens has high hopes for the future. “Lisa and I hope that SheSings will eventually become as grand as the OBF [Oregon Bach Festival] — obviously much different, but very legit as well!”

SheSings 2013 runs June 21-23 at The Shedd; $15-$45. See womensacapella.org or theshedd.org for details.