Bay seniors know they are not the intended audience for the SF Symphony’s new youth-slanted Soundspace in the bowels of Davies but what ushers are going to stop us from coming to hear the edgy music performed there? Its imaginative programming like surreal cabarets and minimalist choirs, not to mention state-of-the-art acoustics, sound intriguing. Go early as there are not many chairs and most of the audience stands. Just like what we used to do at the Fillmore. Cocktails and small bites.