Chapter 10· Groove OS 1.4

ARP

Play along as you read: Play it live opens a working FM-1, running its real software, on the screen this part of the page is about. Tap a control's name in the text to find it on the panel.

The arpeggiator turns a held chord into a pattern of single notes, in time with the loop, on the selected track. Hold a chord, pick a mode and a rate, and the picture shows exactly what it will play. LATCH keeps it going after you let go, and PRINT records it onto the track.

Switching it on

Press . The arpeggiator switches on for the selected track and opens its screen. Hold some keys: the arpeggio plays them, in time with the tempo. Press again to switch it off and return to TRACKS. (SHIFT is held down) opens the screen without switching anything.

Change the chord whenever you like: the note that is playing finishes, and the next step plays the new chord, in time. Nothing is cut short and the arpeggio never jumps off the beat. A new chord starts from its first note; a key added to the chord you hold joins the pattern where it is. Only when the arpeggiator has rested (nothing held for a whole step) does a chord start it at once: straight away when the music is stopped, and on the step it was played on (or the next one, if it came late) when the music plays.

There is one arpeggiator in a project, and it plays on one track at a time. A track plays either its arpeggiator or its sequencer, not both: if the sequencer is on the selected track, the button says SEQ ON THIS TRACK and nothing changes. The arpeggiator holds up to ten notes. Selecting a track whose pattern is on switches the arpeggiator off (SEQ: ARP OFF), so there is never more than one generator on a track.

The knobs

Knob	Values	What it sets
`MODE`	`UP`, `DOWN`, `UPDN` (up and down), `RAND`, `ORDER` (the order you pressed the keys)	The order of the notes.
`RATE`	`1/4`, `1/8`, `1/8T`, `1/16`, `1/16T`, `1/32`	How fast.
`OCTAVES`	1 to 4	How many octaves it climbs before starting over.
`GATE`	10 to 100 %	How long each note sounds within its step.

Try it·On the FM-1

Turn K1 to change the order the chord's notes come in: UP, DOWN, UPDN, RAND, ORDER.

K1

The picture

The picture is the pattern the arpeggiator will play from the chord you hold, over one bar. Each colour belongs to one knob: the blue line is the order (MODE), the green ticks the RATE, the yellow rules are the OCTAVES it climbs through, and the orange blocks are the notes as long as the GATE. The playhead is the orange line that moves. The keys you hold are listed down the left. With no keys held it draws A, C and E, so turning a knob always shows you what it does.

opens the menu.

Row	Values	What it sets
`LATCH`	`ON`, `OFF`	`ON`: the arpeggio keeps playing when you let go, until you play a new chord.
`SWING`	`OFF`, 1 to 75 %, one a click	Every second step later, by that share of a step.
`VELOCITY`	`PLAYED`, or 1 to 127	Every note at the velocity you played, or at a fixed one.
`CHORDS`	`OFF`, `ON`	The chord pads of KEYS (`ON` is `PADS`, the same switch as ): with them on, one pad arpeggiates a whole chord. `PLAY` is set on KEYS.

Recording the arpeggio

The arpeggiator can be recorded in two ways.

While you play it: with on, its notes are written at their exact grid time (they are never quantised, because they are already on the grid).
As a print: hold a chord, and press . The arpeggio is written onto the track's loop as one take, which takes back. After that you can switch the arpeggiator off and the track plays the printed notes.

Troubleshooting

What happens	Why, and what to do
Nothing happens when I hold keys	The arpeggiator is off. Press .
`SEQ ON THIS TRACK`	The track's sequencer pattern is on. Press to switch it off, or select another track.
The arpeggio stops when I let go	`LATCH` is `OFF`. Turn it on in the ARP menu.
The arpeggio keeps playing after I stop the music	`LATCH` is `ON`: it plays until you play a new chord, music or no music. Press to turn it off.
The arpeggio plays the wrong track	The arpeggiator plays on the selected track. Select the track you want first ().
The notes are all one loudness	`VELOCITY` is a fixed value. Set it to `PLAYED`.
`SHIFT + SAVE` does nothing	Hold a chord first: PRINT needs notes to print.