Ears still ringing from the Jazz Fest? Did the blues break your heart and give you a headache? Don't expect the city to do much about it. | "Noise levels are the responsibility of the promoter," says City spokesman Mike Keane. | The city issues permits for outdoor festivals within the city limits, but it doesn't routinely monitor noise levels. If someone complains that a band performing outdoors is too loud, the police may respond, Keane says. As for indoor volume, the city does little. | The city tried an experiment at one outdoor festival held downtown years ago: it limited performances to 90 decibels - the same volume typically given off by lawnmowers, shop tools, truck traffic, and the subway, says the American Speech-Language-Hearing Association. City officials set up meters in the festival tent and continually measured the sound, Keane says. But complaints still came from as far away as the area around I-490 and Winton Road. | Since volume is often the price concertgoers pay to watch live music, maybe next year's hot festival accessory should be earplugs. After all, leading health agencies recommend hearing protection for prolonged exposure to loud noise.