for all those who are interested:
the AAC encoder of nero 6 now supports the use of SBR for bitrates below 96 kbit/s.
that will enhance quality at low bitrates a lot (this technique was used for mp3pro).
but you need special plugins to hear this extra SBR data.
there is now a SBR winamp 2 plugin available:
look for john33's new compile in this thread: http://www.hydrogenaudio.org/index.p...pic=6428&st=50