Hmm, true! Just set the ratio so that the carrier multiplier is high and the modulator multiplier is low (makes the modulation as slow as possible in relation with the carrier frequency).
Tips... experiment more! Also, try pressing the octave and 5th buttons in the wave editor and modulate with that (it mixes the wave with itself creating a fat harmony). It's a bit like if you had one extra modulator that also modulates the carrier. Related to that, I'm working on a better waveform generator/editor (attn. n00bstar).