One of the constant problems plaguing the scene in San Francisco is clubs being located in "mixed use" areas that are both commercial and residential. In SoMa, for example, which used to be primarily industrial wasteland, you had a perfect location for clubs; they could pump the beats at night and no one cared because no one was there. But then, during the boom, there was a lot of residential development in SoMa (really the only part of SF left to develop) and there were inevitable conflicts between residents who wanted their quiet and night and the club goers who wanted to party. In recent years these problems have only gotten worse as limitations on available space force clubs and residential developments into ever closer proximity.
The case of Club 6 on 6th Street is shaping up to be a test case of how to deal with so-called "mixed-use" areas. As reported by Steven T. Jones in the San Francisco Bay Guardian (a report that has caused some friction to erupt between that paper and local politics blog beyondchron.com), Club 6 is located in the basement of a building that also houses a residential hotel, and the sound from the club reverberates throughout the building. The club owner has allegedly taken steps to improve the soundproofing, but, having been in Club 6 on a couple of occasions, I can tell you that the bass will vibrate the fillings out of your teeth. Given that Club 6 tends to host mainly hip-hop and reggae events, where you're going to hear a lot of music with long, deep, bass sounds, I'm not particularly suprised to hear that this sound travels beyond the ceiling of the club (a little physics lesson here, at least as I've learned it: waves have actual length, and in the cases of long waves, which are at the bass end of the spectrum, you won't even hear the sound unless you're at the end of the end of the wave itself. This is why if you stand right on top of a sub woofer, you won't hear the bass nearly the way you will if you step back several feet. For a long 30hz wave, which is about as low as humans can hear, it takes about 20-30 feet to get the full impact of the wave. Also, bass is omnidirectiona and notorious for travelling through walls, while upper frequencies travel in straight lines and are reflected back). I'd be curious to see if Club 6 hosted rock bands, which tend to get more into the upper frequency ranges than lower, and kept the music to the same decibel level, if they'd have the same problems.
There's a hearing on June 5 that will determine what's going to happen in this situation. It seems pretty unlikely that Club 6 will be allowed to operate in the same way for much longer, esp. when it's being portrayed as a fight between irresponsible partiers and the disenfranchised (as evidenced by the comments to Steven's article). Eventually, however, some kind of city-wide compromise is going to have to be worked out or soon there won't be any place where a club can safely operate that is also not totally inaccessible.