Can't change voice and can't disable not desired modules

I'm trying to use gnome-orca --> speech-dispatcher --> festival

It works but:

* I tested speech-dispatcher putting festival in server mode and using spd-say -o festival. I got always the same voice, kal_diphone. I tried different solutions modifying speechd.conf and tunning festival configuration files. No success.

work-around

$ sudo su
# cd /usr/share/festival/english
# mv kal_diphone kal_diphone-backup
# ln -s ../catalan/upc_ca_pep_hts kal_diphone

* I didn't find also the way to disable not desired modules with speechd.conf. I need only sd_festival

work-around

$ sudo su
# cd /usr/lib/speech-dispatcher-modules
# mkdir backup
# mv sd* backup/.
# cp -p backup/sd_festival .

Any idea?

My system is Lubuntu 16.04 LTS 64 bit up-to-date.