ya se ha descubierto el tema de las voces de SE y el titulo
In order to get the voice appear, you need to:
1) have a save file with 012 story mode (the 12th war) cleared, and
2) PSP's data is on or after 01 Apr 2011.
Now according to your saving time of your latest save file, the following Character's voice will appear on the next day of that saving time. (Eg. if your last save was on 13th, set your PSP date to 14th and you will get the voice) Some voices need special timing though:
The main good guys: on 1st to 13th of each month respectively.
(WoL, Firion, OK, Cecil, Bartz, Terra, Cloud, Squall, Zidane, Tidus, Shantotto, Vaan, Lightning)
The main bad guys: on 21st to 30th respectively.
(Garland, Emperor, CoD, Golbez, Exdeath, Kefka, Sephiroth, Ultimecia, Kuja, Jecht)
Some of them could appear more than 1 day:
Garland also on 31st, Exdeath also on 15th, Kefka also on 16th, Kuja also on 19th
Character voice that needs special conditions: ([HH:MM] = [Hours:Minutes]) XX=anything, doesn't matter
Gabranth: [12:XX am] or [12:XX pm] or [XX:12] of 12th
Prishe: [11:XX am] or [11:XX pm] or [XX:11] of 11th AND Prishe has to be unlocked
Gilgamesh: 15th AND Gilgamesh has to be unlocked
Chaos: could appear anyday will a chance of 5% only after Feral Chaos is unlocked
Cosmos: special day
Great Will: [01:XX am] or [01:XX pm] or [XX:01] of 1st AND must have finished 013 story mode (13th war), OR (one time only) the next boot after finished 013 story mode.
Aerith: [07:XX am] or [07:XX pm] or [XX:07] of 7th/17th/27th AND must have Aerith Assist