iTunes4/AAC again

[a l a n t h o m p s o n]

has anyone noticed that AAC encoded files appear to have an inherently 
lower volume level?

typically, i encode/rip my cds at 192/vbr/etc..

last night i encoded nothing's shocking (janes addiction) with AAC just 
to play around.  i used 160kbs/48Khz sampling rate, stereo/using 
velocity engine (whatever that means).

so, i go to play one of the more dramatic songs on that album.  hmm.  
sounds good.  i have the sound sticks setup and i am very happy with 
them.  but last night, to really get anything out of my listening 
experience, i had to turn ituenes' volume to its max setting, and the 
main volume up to at least 3/4 - this to get the same sound as half 
volume setings for both itunes and the main volume setting with, say, 
classic girl, stolen from the net, ripped by god knows who, at 128kbps.

i notice the same for purchased music from the "music store."  so, with 
the who's "bargain," or the talking heads' "burning down the house."  
great sound.  have to crank it up to get decent sound levels.

i have the sound enhancer feature turned off, am using the eq (rock 
setting), pre-amp level flat (default).

so anyone?

--alan