You can, just do

sudo nano /etc/mpd.conf

find this part

# This setting enables on-the-fly normalization volume adjustment. This will
# result in the volume of all playing audio to be adjusted so the output has
# equal "loudness". This setting is disabled by default.
#
#volume_normalization "no"

and uncomment volume_normalization . It will become like this:

volume_normalization "no"

then ctrl + x , and exit

then restart mpd with

sudo /etc/init.d/mpd restart

Et voilà! Let me know!