Is it possible to do Frequency Modulation with Halion 6 ?
No it is not possible to do FM. You can’t use the oscillators as modulation sources for other oscillators.
Actually let me somewhat revise my statement. I was looking through the Halion manual and one of the oscillator types in synth zone is “cross modulation”, so you can get FM-like tones:
CM (cross modulation) provides a combination of two oscillators where a master oscillator is modulating the pitch of a slave oscillator (sine, triangle, saw, or square) at the rate of the audio sample. The Waveform parameter adjusts the pitch ratio between slave and master oscillator, resulting in a sound close to frequency modulation.
You can’t change the modulator signal (I think it’s a sine wave) but you can set the carrier to sine, triangle, or pulse. You can modulate the ratio with the LFO’s but that’s about it.