Club systems vary wildly. I usually provide my own gear, and it's quite high end (JBL SRX700 series subs, and PRX 625 mains), and is more accurate than most home stereos, while also being dangerously loud. But, I can't hear the difference between a ~200kbps mp3 and a FLAC through that system. I probably couldn't consistently hear the difference on my headphones (also high end) or my studio monitors (again, quite high end), either.
That said, a 128kbps mp3 through a really loud system tends to sound harsh. It is definitely audible, even to untrained ears. But, anything above 192kbps, or so, is fine and any flaws that might be audible in an ideal listening environment are lost in the general noise of the club environment.
That said, a 128kbps mp3 through a really loud system tends to sound harsh. It is definitely audible, even to untrained ears. But, anything above 192kbps, or so, is fine and any flaws that might be audible in an ideal listening environment are lost in the general noise of the club environment.