Ok i found a solution:
This is a simple solution for load and play a ogg sound using OpenAL..
The function LoadOGG do the work and get all information you need for every operation: size, format, frequency;
then store all the raw audio data in a vector, then loaded in a buffer ready to be played.
Ogg_Load_Play.rar
Source:
https://www.gamedev.net/resources/_/technical/game-programming/introduction-to-ogg-vorbis-r2031
In this way every ogg file should be loaded without any problem and from every source.
The proof is that now my "final.ogg" load and play..
( I would you take a moment on this Link if you are interesting in something more complex )
PS: if u want use proper this files in a LE project, Audiotest function must be called before any LE setup, pratically at main function start, this because LE use a proper Openal context not compaticle with this simple solution.
PPS:
According to http://wiki.audacityteam.org/wiki/OGG ogg file has usually a variable bit rate, but:
"When exporting to OGG in Audacity, you choose a quality setting from 0 to 10. This tells the encoder a very approximate average number of bits to use for the encoding" ( as listened next in the same page )
and then says
"Audacity's default OGG export quality setting is -q5, implying a bit rate of approximately 160 kbps."
From this you understand that LE has a limitation because it's fixed sound bitrate property, that doesn't allow a range.. for that audacity exported files, that has a fixed bitrate, are loaded without any problem, which does not happen for file with variable bitrates( most common files for what i have seen around ).