About expressions

In OpenUtau, parameters such as volume, velocity, Voice Color (append subbanks), modulation, and UTAU flags are collectively referred to as “expressions.”
Additionally, there are expression types that allow drawing curves rather than applying them to individual notes.
The available expressions vary depending on the renderer.

Edit expressions

Use the arrow by the expressions to select which one you want to edit.

The gear icon will allow you to view the expression settings for the whole project.

Click to set a value, and right click to reset it to the project default.

Default expressions

Name	Abbreviation	Purpose	Range	Default
Velocity	VEL	Consonant velocity (stretch/shorten preutterance)	0 - 200	100
Volume	VOL	Note volume	0 - 200	100
Attack	ATK	Envelope starting volume	0 - 200	100
Decay	DEC	Envelope ending volume	0 - 100	0
Voice color	CLR	Utilizes voicebank appends/colors	No range, options	Blank
Resampler engine	ENG	Change resamplers on the fly	No range, options	, worldline64.exe
Gender	GEN	g flag (formant shift)	-100 - 100	0
Breath	BRE	B flag (breathiness)	0 - 100	0
Lowpass	LPF	H flag (low pass filter)	0 - 100	0
Modulation	MOD	Note modulation from original pitch	0 - 100	0
Alternate	ALT	Alternate aliasing for duplicates in oto.ini	0 - 16	0
Tone shift	SHFT	Allows for selecting pitch alias	-36 - 36	0

VEL (velocity)

This corresponds to UTAU's Consonant Velocity. This affects the length of the fixed region of the OTO, which is the beginning of the note/phoneme.

VOL (volume)

This raises or lowers the overall volume of the note/phoneme.

ATK (attack)

This raises or lowers the volume of the beginning of the note/phoneme.

DEC (decay)

This lowers the volume of the rest of the note/phoneme.

ENG (Resampler Engine)

Selects resampler engine used to render this phoneme. If value is "", the engine selected in Preferences is used.

MOD (modulation)

This determines how much the pitch is flattened from the original recording. By default this is 0, or completely flat.
This is an obsolete feature and is not recommended for use.

MOD+ (modulation plus)

Reflect the original pitch of the voicebanks on the gray pitch line in the piano roll.
Unlike MOD, it can also be used with VCV/CVCV.

Options Flags (Non-Numerical Flags)

Add a flag. Change its type to "Options" and set "Option Values" to ",e". You will be able to use an expression to add nothing or "e" to resampler flags.

Other expressions

All other expressions are like flags in UTAU.

Edit expressions lineup

Expressions are saved per-project. To edit expression settings, go to Tools > Expressions.

Adding expressions

Use the + and - buttons in the lower left corner to add and remove expressions. Some expressions cannot be removed. There are two types of expressions, numerical expressions and fixed options.

For numerical expressions fill out the name, abbreviation, resampler flag, minimum, maximum, and default value. The resampler flag must be a single flag by itself without any numbers. If you want the whole project to have a certain value (eg. Mt+20) please put the number in the Default box.

For options, fill out the name, abbreviation, checkbox, and option values. This is for flags that don't take any numbers, like for toggling between stretching and looping.