Dear Glai: Bojack is right: the pre-out is the best way to go.
Now, the integration of subwoofers in an audio system is more much more than only " more bass ". Take a look to these links:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&27&4#27
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&31&4#31
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&84&4#84
Regards and enjoy the music.
Raul.
Now, the integration of subwoofers in an audio system is more much more than only " more bass ". Take a look to these links:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&27&4#27
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&31&4#31
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&84&4#84
Regards and enjoy the music.
Raul.