preenfm3 v1.06g — HQ oscillator interpolation & randomizer improvements

HQ Oscillator Mode

A new HQ oscillator quality tier is now available in the engine decimation setting, above Full.

When HQ is selected, linear interpolation is applied at the wavetable lookup site for all six oscillators. This reduces the stair-step aliasing that can appear in high-partial FM spectra, particularly on complex algorithms with multiple carrier operators. HQ also works correctly with the Warp parameter — the warped-phase and interpolation transforms are combined into a single lookup without quality loss.

HQ is mutually exclusive with wave decimation: if a decimation mode is active, interpolation is suppressed and the decimated output is used instead.

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Preset Randomizer Improvements

The randomizer (Oper / EnvT / IM / Modl) has received a large number of tuning and feature improvements.

Oscillator waveforms

• Percussive mode (EnvT = perc) can now occasionally pick user waveforms (USER1–USER6) for individual operators (~10% probability), adding custom transient color to drum and percussive patches.
• Pad mode (EnvT = pad) now draws from the full waveform palette with a strong sine bias (85% sine, 15% everything else), rather than being restricted to sine/saw/triangle.

Percussive envelope and LFO timing

• Percussive sustain and release times have been tightened (sustain max 0.5 s, release max 2.5 s) so randomized drum patches no longer have unrealistically long tails.
• Percussive LFO one-shot frequencies were raised (floor 3 Hz, ceiling 10 + 3×Modl Hz) so transient modulation — pitch drops, filter sweeps — completes well within the shorter envelope window.

Pad LFO improvements

• Pad LFOs can now use slow multi-shot sync modes (2–8 cycles, 40% probability), so modulation evolves and then settles rather than cycling indefinitely.
• Pad LFOs can carry a non-zero bias offset (±0.3) for asymmetric movement. This is only applied when the LFO is not routed to amplitude-sensitive destinations (MIX_OSC*, ALL_MIX, FILTER*_AMP). If the randomizer assigned an unsafe destination, it is automatically rerouted to a safe one before the offset is enabled.

Stability fixes

• All releaseLevel values are now forced to 0.0, preventing voices from dying at non-zero amplitude (clicks) and closing an edge case where a modulator envelope could loop indefinitely.
• Output mixer gain is normalized by the algorithm's carrier count, keeping the summed output level consistent regardless of whether the algorithm has 1 or 6 carriers.