The procedure is quite simple, first play Wolfenstein3D to hear if the channels orientation and speaker placement is correct, you can skip this step if you sure the left and right speakers are correctly placed.
Or you can touch the Tip of the 1/8" TRS plug and listen for noises on the Left speaker.
Doom: Test if PCM/digital sounds come from the proper side, or are they reversed.
Duke3D: Test the sound sample in the Setup utility without the reverse switch (unticked), should sound correct.
Tie Fighter: imuse.exe setup utility, in the sound test the ship flyby from left to right, reverse switch unticked.
Descent: setup.exe, do the sound Test (Twice, accept then again, important) and hear if the channels are correct with reverse stereo disabled [make sure StereoReverse=0 in descent.cfg file].
Quake: sound should be correct.
* Please select the SBPro setting in all game setups.
Also, please test THIS SBTEST app (attached) by the developers of DOSBox and report what you hear, this is the most important test.
On the CT1600 I hear the sound twice on the Left channel, while in DOSBox it is first Right then Left.... none of my SBPro (and clones) cards behaves like this.
The SBPro plays stereo by interleaving the left and right bytes, and it is thought that the CT1330A behaves differently that the CT1600, this is what we trying to figure here.
Made a little test app that plays 8bit stereo with and without a single byte start transfer.
Here are some results with my SBPro collection:
These tests should suffice to tell how the CT1330A behaves in contrast to CT1600.
I really appreciate your help, this will help the developers of DOSBox understand more and fix the emulation, because clearly they still have issues with understanding how the Stereo of the CT1330A works and very well may be that it is emulated wrongly.
Invert Left/Right Audio Channels Stereo Sound?
I attached a small soft SBCHECK which tells what card it is and what DSP.
Also SBTEST by DOSBox developer Harekiet to test how the SBPro behaves.