Waldorf Quantum/Iridium: apply the modulation and envelope laws of the firmware 4.0.6, convert the filter LFO, the glide and the polyphony

[douglas-carmichael]

Stacked on #427, which is stacked on #426 and #425; the diff shows all four until those land. All four are rebased on main.

Read out of the Iridium MK2 firmware 4.0.6 and measured on an Iridium MK2 with OS 4.0.6.

Pitch modulation amounts are squared. ModMatrix::calc squares the amount of a slot on the destinations Pitch and Osc1-3 Pitch, keeping its sign - these destinations are registered with the squaring flag and the amount goes through fabs - and the voice multiplies the sum with 24 semitones. Pitch envelopes and vibratos were written and read with the linear semitones / 24: an amount of 50 % plays 6 semitones, not 12, and the amount written for a vibrato of 50 cents plays about 1 cent. Both directions use the law of the device now.

Envelope times. The sound engine plays an attack, a decay or a release as 60 x 10^(3 (x - 1)) - 0.06 seconds; the display shows - 0.001, the law which was used. Every stage played 60 ms short and every stage below 60 ms was written as instant. The creator writes x = log (1 + t / 0.06) / log (1000) and the detector reads with the same law. The minimum of the de-click rule becomes 0.01 s, which writes exactly the value of the former 0.07 s - the length the device played in the test which established that rule.

Matrix destinations by name. The list of destinations grew with the firmware: the VCA is 107 up to the format version 13, 108 in 14 and 117 in 15, Filter1 Cutoff 99, 100 and 109. The loader resolves every enumeration by the name in its hint (PatchLib::migrateIOAreaToStagingArea calls Param::DiscreteNameToIndex) and uses the stored index only without one. The detector matches destinations by the hint and falls back to the index of the file's version, which finds the tremolo of patches written by older firmware and no longer takes a version 8 slot on LFO1 Speed - index 117 there - for a tremolo. The creator writes the index of the version it writes.

New

• An LFO on Filter1 Cutoff is read and written (slot 6, LFO 3). This destination is not squared; the full amount moves the cutoff by 135 semitones, the range of Filter1CutOff.
• The portamento of a source is written as the glide: GlideOnOff, GlideRate (2 x^2 seconds, the same time for every interval), GlideType Legato for a legato source.
• A polyphony of 1 is written with the mono mode; a mono patch is read with a polyphony of 1.
• A key tracking which all key-tracked zones of a group share is written as Osc{i}Keytrack.

Fixed

• A pitch envelope whose start level is not set (-1) was written as one which starts at a level - no attack, and the attack time of the source as its decay - so e.g. the decay of an SFZ pitch drop was lost. The test is getStartLevel () > 0 now; AbstractNKIMetadataFileHandler writes Kontakt pitch envelopes with the same != 0 test.
• The hint of a negative pitch bend range was written as --2.

Measured on an Iridium MK2 (OS 4.0.6), recordings analysed by pitch tracking:

test	expected	measured
free envelope at full level into Osc2 Pitch at +50 %	6 semitones (squared), 12 (linear)	6.00 semitones at A4 and at C5
converted vibrato of 50 cents at 5 Hz	+/-50 cents	+/-49.97 cents at 4.999 Hz; the previous conversion: +/-1.04 cents
converted SFZ pitch drop of 12 semitones over 0.5 s	starts an octave high	+12.02 semitones, linear slide; the previous conversion: no slide
GlideRate 0.7071	1 s for every interval	1.000 s over 200 and over 400 cents
unipolar square LFO at +8.89 % on Filter1 Cutoff	an octave	11.75 +/- 0.5 semitones, every 1.000 s
stages written for 0.07, 0.1, 0.25, 0.5, 1 and 2 s with the display law, EnvelopeVariation 0	t - 0.06	0.011, 0.041, 0.190, 0.441, 0.940 and 1.940 s for attack, decay and release

Checked

• QPAT corpus: 19 of 19.
• All 1,787 factory patches analyse without an exception.
• An SFZ with a polyphony of 1, 50 % key tracking, a vibrato, a pitch envelope, a cutoff LFO and a tremolo round-trips through QPAT to SFZ and to QPAT; envelope times round-trip exactly.
• Reading the factory and the Flux Vol. 1 patches changes only the pitch amounts, finds 3 and 4 cutoff LFOs and moves one tremolo to the real VCA slot.
• Writing Espen Kraft's PX Vol. 2 (43 presets) and an E4B bank (474 presets) changes only envelope times; the sample maps are identical.