Screw me. Seems I plugged the speakers into 'rear' output of the card, hence the situation. However, after plugging into another jack, PCM and FM (emulation) are heard, but no GM music in DOS mode. Is it what supposed to be?

I can't speak for the card you have, but on mine (Diamond Monster Sound MX300) I believe General Midi only works with a daughter board attached to the waveblaster header. The reason you don't hear anything is probably due to the absence of a synthesizer on the gameport.

In Win98SE and its DOS box I have GM music (software it seems), I can even load sound banks into system memory using Aureal control panel. I already tried loading AWE32 ROM bank and it sounds pretty much alike the original.

If it's a software synth then it's not going to work under DOS, as there is no facility to initialize it or to load sound banks.

The Vortex 2 has bad digital support in DOS, in my opinion. I think it locks up the computer when playing samples in the Indians Jones Atlantis game, as one example.

My experience has been much better. I love the Aureal SQ2500 for DOS, but yes, you do need to have a wavetable card on the header. The FM synth is really bad.

Some cards require the SB link cable for dos mode.