You should use the same source for a specific sound if you don't need to play it simultaneously in different positions.
Or use a fixed number of sources (2 or 3) that you turn with.

Other temporary solution is to add a custom script to delete objects from a c++ plugin and call this script from lua when the sound finished playing. We can add this script to the trunk later.

Two scenes, Scene-1 and SNDscene.
All sounds are on SNDscene.

I'm using sounds in a OO way, so i can play a whole collection with just few lines,
for playing i'm cloning the sound from SNDscene to Scene-1,
and i'm setting the setPosition argument to place it to the object i want.

The problem is, after a while (120~ uses), it stop playing for good.
in some other projects it stops playing after 15~ uses

here's a project to show the problem : Soundbug
(this one stops sounds after 120~ uses)

Press these keys to play sound at :
4 = left
8 = front
6 = right
2 = back

Any idea what's going on ?