[X4U] AIFF-conversions in iTunes kill decibels

[Herbert Marouschek]

My converting AIFF-files with iTunes (v 7.1.1) to AAC / MP3 typically  
results in volume losses of between 3 and 8 dB.

Is this the way it is, or is there a way to preserve the volume level?

thanks...
Herbert Marouschek