“The Hammer of the Hammond,” the “Pulverizer of the Piano,” the “Razer of the Rhodes”—no matter what nickname Robert Walter is given, he shines as one of the heaviest jazz-funk keyboardists this side of Philadelphia. The founding member of the Greyboy Allstars now plays with his own group, Robert Walter’s 20th Congress, known for their funky shows bursting with energy. This is the kind of funk that hurts not to dance to. They play with openers the Heavy Guilt on Sunday, Sept. 8, at the Sweetwater Music Hall. 19 Corte Madera Ave, Mill Valley. 8pm. $17. 415.388.3850.