Avatar ST is most suited for a large variety of pads, soundscapes, atmospheres or related FX sounds but can do other sounds like e.g. certain kinds of basses too.
The 16-Step Modulator allows sounds to be fairly rhythmical in various ways if required. Also you can have one section step-modulated while the the other is not as there are two complete sections with oscillators, modifiers, VCA EG, Delay, Pan and Reverb send, plus a grain processor and a multimode filter to be inserted via different audio routings. In addition there are a lot of modulation options you might select from in order to tailor your sound.
2 x 2 PCM wave oscillators with 384 waves in 3 banks.
2 x Osc Mix section with one XY-Pad plus mix option for direct and step modulated out.
2 x Mystify with three selectable types (Bright, Soft, Dark).
1 x Grain Processor.
1 x Filter with 4 types (LP, HP, BP and Feedback) incl. 1 ADSR EG.
2 x VCA EG (ADSR).
2 x Delay, 2 x Pan.
7 x LFO, 1 x S&H, 16 Step Modulator, Keytrack and Modwheel.
1 semi-parametric 3-Band Stereo EQ, 1 small Reverb for adding some nice flavour.
16 voices, 8 Lazy Buttons.
Major differences between Basic Free and Pro version:
Pro Version = 16 voices, 128 internal patches, 384 internal waves (3 banks).
Basic Free = 4 voices, 64 internal patches, 256 internal waves (banks #0 & #2), SF2 & wave loading only with Osc B2.