ORGANSOUNDpulls tonewheel drawbarslight / dark

ORGAN

ORGAN is a tonewheel organ (an organ that builds each note from a set of sine "wheels") played from its drawbars. Pull the bars up and down to set the registration (the mix of pipe pitches), then add percussion for a struck attack.

pulls tonewheel drawbars

Half

SOUND

Reach it

a custom build, FELUCCA_ORGAN=1 (else on ANALOG)

ALGORITHM

PERC

Engine

ORGAN

Factory sounds

9

Playing it

MAIN holds the three drawbars that matter most, 16', 8' and 4', plus PERC. With 8' alone you hear the plain note; 16' adds the octave below and 4' the octave above. A drawbar's numbers work as on the console: 0 is silent, and each step up adds about 3 dB (decibels; 3 dB is about 1.4 times the level).

PERC adds a decaying 2nd (4') or 3rd (2-2/3') harmonic to the attack, fast (about 0.2 s) or slow (the S settings, about a second). As on the real instrument it is single trigger: only a note struck with no other key held gets it, so legato lines stay smooth and detached notes click and pop. Every note also starts with a short key click, the sound of the key contacts closing.

ORGAN is on the sidelines: SQRL-1's build leaves it out. A custom build with FELUCCA_ORGAN=1 brings it back, picked on the PAIR page (hold HOME, tap GLO, KNOB 1). Without it, an ORGAN sound in a project or a saved sound plays on ANALOG.

MAIN

Pages

BARS LOW

The console's first four drawbars: 16', 5-1/3' (the fifth above the note), 8' and 4'.

Knob	Label	Range	Starts at
1	16'	0 .. 8	8
2	5-1/3	0 .. 8	8
3	8'	0 .. 8	8
4	4'	0 .. 8	0

BARS HIGH

2-2/3' and 2', then TOP, which moves the console's three highest bars (1-3/5', 1-1/3' and 1') together, and PERC again. Nine drawbars do not fit on eight knobs; TOP is where they meet.

Knob	Label	Range	Starts at
1	2-2/3	0 .. 8	0
2	2'	0 .. 8	0
3	TOP	0 .. 8	0
4	PERC	OFF 2ND 3RD 2ND S 3RD S	3RD

ORGAN and WHEEL

Felucca's own organ, WHEEL, is not built into SQRL-1: ORGAN covers it, and leaving it out frees flash and RAM for the rest. A project or preset that holds a WHEEL sound plays it on ORGAN's first sound.

ORGAN sets all nine drawbars directly (the top three as one) and sums them into one wavetable, which it rebuilds only when a bar moves. A voice costs one table read a sample whatever the registration. It has no rotary speaker of its own; use the ROTOR insert.

Where it comes from

firmware/src/eng_organ.c, organ.c and organ.h, from databurn's sound engines (MIT). The drawbar footages, the 3 dB steps and the single-trigger percussion follow the Hammond console.