Hard limiting can add a few dB, very often without any real change in the sound. I can't speak to all possible capabilities but the Hard Limiter in Cool Edit has four parameterslimit maximum amplitude to __ dBboost input by __ dBlook ahead time __ msrelease time __ msIt is going to depend on the material but for older, more dynamic stuff you can often get 6 dB without any pain (limit max amplitude to -6 dB), maybe considerably more in some cases.I always use 0dB in the boost parameter. That way, nothing except the extreme peaks are changed by the hard limiter (i.e. for a -6dB setting, only peaks higher than -6dBfs will be effected). After limiting, I amplify the entire waveform by the amount I want (which in the example here would be at least +6dB without clipping). Experimentation will tell you what works for any given track.I've also used the relatively simple Dynamic Range Processor in Cool Edit to good effect on some music. It isn't going to give you the same thing as a good multi-band compressor, and is unlikely to work satisfactorily on some, perhaps much music (again, depending on the type of material), but I've found it to work well enough for my purposes a number of times.