That's questionable. Again, I don't believe anyone who claims things about sound unless they're doing a blind test with well-encoded files. You need to make a stronger argument than "they feel bad". Why? What frequencies are not being reproduced accurately and why do you think that makes them sound bad?
A "2 kW" sound system doesn't have any special properties by nature of its wattage, but a club does have a sound system which can reproduce frequencies that are below that what a typical home (or studio) system can. MP3s are usually encoded with a high-pass filter (usually around 20 Hz), and some club systems can get down close to that range (more often 30 Hz), but it's very questionable that they're hitting border.
It is true though that on those types of systems, you're more likely to expose the effects of doing things like double lossy encoding, use of bad encoders, etc.
The further away from the "ideal" reference listening case of high fidelity headphones in a quiet room, the less likely that the assumptions behind the psycho-acoustic model used in the lossy codec are valid. Frequencies can be missing because of shitty speakers, room cancellation, or deliberate post-processing, and expose sounds that the codec thought would be masked. On my surround sound, the difference between a 320kbps mp3 and a FLAC is not only audible but obvious when played in Pro Logic 2 mode, which exploits phase information to place different sounds in different speakers.
A "2 kW" sound system doesn't have any special properties by nature of its wattage, but a club does have a sound system which can reproduce frequencies that are below that what a typical home (or studio) system can. MP3s are usually encoded with a high-pass filter (usually around 20 Hz), and some club systems can get down close to that range (more often 30 Hz), but it's very questionable that they're hitting border.
It is true though that on those types of systems, you're more likely to expose the effects of doing things like double lossy encoding, use of bad encoders, etc.