No need for apology. That is what this forum is for. Don't think of sfz as a sound file in the same sense as you would a fla, wav, ogg, mp3, etc. The sfz files in session drummer actually use the flac files you are trying to access. Flac files are high quality audio files that use a lossless compression method. Sfz files within SD3 contain info tat points to the actual sound file sources, among other things. You cannot make a flac a multi-sample. There are few widely available, non-proprietary file formats that allow for multi-samples. If you open up one of the sfz files using notepad it will give you a better idea what the sfz file is. Here , for instance is what the sfz file for the high hats for the 808 kit:
// TR-808 Hi-Hats 1
// Closed Hi-Hat
<group> key=42 loop_mode=one_shot
<region> group=1 off_by=1 lovel=0 hivel=127 sample=RhythmMachines TR-808 Hats\ClosedHH.wav
// Closed & Open
<group> key=44 loop_mode=one_shot
<region> group=1 off_by=1 lovel=0 hivel=127 sample=RhythmMachines TR-808 Hats\BothHH_0.wav
// Open Hi-Hat
<group> key=46 loop_mode=one_shot
<region> group=1 off_by=1 lovel=0 hivel=127 sample=RhythmMachines TR-808 Hats\OpenHH_0.wav
// Closed Hi-Hat
<group> key=22 loop_mode=one_shot
<region> group=1 off_by=1 lovel=0 hivel=127 sample=RhythmMachines TR-808 Hats\ClosedHH.wav
// Open Hi-Hat
<group> key=26 loop_mode=one_shot
<region> group=1 off_by=1 lovel=0 hivel=127 sample=RhythmMachines TR-808 Hats\OpenHH_0.wav
This one is relatively straight forward. It defines all the files and their location this multi-sample consists of , the volume range, loop mode as well note range for each sample. Although the sfz file is loaded on to only one slot in SD3, instructions map the respective sounds to the proper places on a keyboard. The files you are attempting to open would be the files referenced within the sfz file instead of the sfz file itself. A flac or wav will work in SD3 but it will only contain the one sound.