A stereo sound when played as 3d, will be split into 2 mono voices internally which are separately 3d positionable. Multi-channel sounds are also supported, so an 8 channel sound for example will allocate 8 mono voices internally in FMOD. To rotate the left and right part of the stereo 3d sound in 3D space, use the Channel::set3DSpread function. By default the subchannels position themselves in the same place, therefore sounding 'mono'.
it is possible to use stereo assets for panning, but I have some questions about configuring it:
Does Min Extent parameter in Studio’s spatializer settings has the same behaviour as Channel::set3DSpread?
Channel::set3DSpread is a method for setting an ‘angle’ and is there a method to set up a ‘radius’ in which left and right part will be moved from center of event?
Hi Ilya,
That doc is interesting, because I think while it is too relevant to your question, that is definitely not how stereo and above sounds work in FMOD now (Ie a stereo sound does not use multiple voices, it just uses 1, and uses a special pan matrix to compute the panning of all the subchannels). I think this is a hangover from the old hardware sound card days!
To answer your question, set3DSpread is technically totally separate and unrelated to the min extent feature in studio.
set3DSpread basically moves the position of the subchannels around the final speaker array - AFTER the 3d position. So if the sound is directly in front of you, and the spread is set to 90 degrees, the sound will spread the left part of the sound to the front left speaker (ie 45 degrees to the left) and the right part of the sound to the front right speaker (45 deg to the right).
The DSP panner is a lot more complicated than that, and you can graphically see how it works with a extent (which increases or decreases the ‘spread’) and direction (which gives the sound a direction on a circle). In 3D these are set automatically, or you can control it yourself too