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Parameter curves

What is a parameter curve ?

Parameter curves are a fast and accurate way to change the sound of an instrument while music is playing.
As you could read in previous chapters, general digital effect settings, in the "Play tools" palette, enables to change the global volume of a document, as well as bass boost, noise reduction, etc...
These settings apply to the whole instruments of the document. If you change the volume, for example, it affects the whole piece.

Then on each staff, digital effect processors can be inserted in order to add specific effects : Distortion, Flanger, Chorus, Reverb, etc. These are "Effect processors" objects.

From Harmony Assistant version 8.0 (Melody Assistant 6.0), several curves can be related to each staff. Each curve defines the way a parameter evolves during time. The curves are processed in priority in regard to effect processors, but you can use both on the same staff.
A curve enables to control more finely the variation of this parameter.
For each time position in the written music, you can select precisely the parameter value, or make the parameter vary smoothly betwee two time positions.

Here are some samples of use :

How to access curve editing ?

We saw that in scroll mode (the only display mode available in Melody Assistant) or in page mode with control handles enabled (Harmony Assistant only), little icons are displayed on the left of the staff. The third icon from the top is a green arrow. When clicking this icon, a pop-up menu opens.
You can select the curve to be edited. When a curve is currently edited, the staff is grayed out in order to ease the layering between notes and the parameter curve values.

The first menu item resets the standard display and editing mode for notes on the staff.
The next one enables to edit note velocities (power). A red curve joins the notes. The bigger value for note velocity, the higher curve point. By clicking in "Editing" (pencil) mode, you can change graphically the velocity value of each note.

Then, with Harmony Assistant only, you can adjust delay and pressure time for each note. A blue horizontal line shows the delay (offset from the note head) and the pressure time (line length). As for velocity, you can can change graphically these values in "Editing" (pencil) mode.

A second section in the menu grants you the access to other parameters, like volume, panning position, frequency, chorus level...
You can also define parameters that are dedicated to MIDI output management.

Parameters in this second section, contrarily to velocity, delay and pressure time, are not related to the notes, but to the staff itself. Deleting or moving note won't change the curve. It is therefore preferable to adjust curves after having input all notes.

When a curve exists for a parameter, the curve name is displayed in bold in the pop-up menu.

Then, the third section of the menu enables to configure the curves, or to apply changes to existing curves.

How to edit a curve ?

A curve is made of segments (coloured lines) between control handles (little squares). On the left side of the staff, the minimum and maximum value of the parameter, as well as its name. You can configure the parameter, in order to change its minimum and maximum value, as well as its display color.

To add a control handle, click the staff in "Editing" (pencil) mode.
To move a control handle, drag it in "Editing" (pencil) or "Select" (lasso) mode.
To move a curve, drag its first control handle while Shift key is down.
To change several values at a time, include the group of control handles to change in the selection range, the drag one of these control handles.
To split a curve into two parts, click a segment with the delete tool (bolt)
To delete a control handle, click it with the delete tool (bolt)
To delete a curve completely or partially, select the staff then Edit>Erase
You can copy/paste parts of a curve on the same staff, or from a parameter to another.
You can add or subtract a value to the selected range through the apply option in the pop-up menu.
You can fill the selection range (or the whole staff if nothing is selected) with triangle or square curve through the apply option in the pop-up menu.

How the parameters are applied ?

Values of parameters that are displayed as a curve are applied in real-time while music is playing, 200 times each second. The value is read at the required time position in the written score, and eventually calculated to perform smooth changes between two control handles. If, at a given position, there is no segment (that can occur for example if you splitted a curve by deleting a segment), the parameter is not applied.

Some parameters are specific to digital output, some other to Midi only, or to both digital and Midi output.
The array below shows each possible parameter curve as well as its field of action.
Parameter name
Maximum range
Digital output MIDI output
Virtual Singer
Digital tracks
Volume Output level from 0 (quiet) to 100 (loud) Yes Yes Yes Yes
Panning right - left panning position from -100 (extreme left) to 100 (extreme right) Yes Yes Yes Yes
Frequency Pitch variation (pitch bend) from -2400 (-2 octaves) to 2400 (+2 octaves) Yes Yes Yes No
Flanger/chorus power Flanger/chorus power from 0 (no effect) to 100 (maximum effect) Yes Yes Yes Yes
Reverb power Reverb power from 0 (no reverb) to 100 (maximum reverb) Yes Yes Yes Yes
Resonator resonance Resonator (filter) resonance from 0 to 100 Yes No Yes Yes
Resonator frequency Resonator cutoff frequency from 50 Hz to 4000 Hz Yes No Yes Yes
Distortion power Distortion power from 0 to 100 Yes No Yes Yes
Distortion color Distortion color (bass/treble) from 0 (bass) to 100 (bright) Yes No Yes Yes
Treble Equalization : treble from 0 (regular) à 100 (treble) Yes No Yes Yes
Bass Equalization : bass from 0 (regular) to 100 (bass) Yes No Yes Yes
MIDI-specific from a to f User-defined MIDI command from 0 to 16383 (14-bits MIDI parameter range) No Yes No No

If you define your parameter curve to be applied to all staves in the document, it will be applied to any staff EXCEPT if a curve also exists for this parameter in the staff.
It enables to define global curves that are replaced by specific curves in some time ranges in some staves. To ease the reading, it is recommended (but not needed) to group all global curves in the first staff of the document.

MIDI parameter curves

These parameters are specific to your MIDI device and enables to control the non-standard features of your synthesiser.
You can define up to 5 MIDI parameter curves in each staff.

Note :
Because these parameters are specific to your synthesizer, they can have different effect on other hardware device than yours.

To define this kind of parameter, open the parameter setting window and select the parameter in the list. Then input a text that defines the command to be sent to your synthesizer. The manual provided with your MIDI hardware should describe these specific items.

Command input is made in hexadecimal (16-based digits, each digit being a valued between 0..9, A..F). The value read on the curve replaces characters 'm' and 'l' in the command line.
'll' represents the less significant bits (LSB) of the value, 'mm' represents its most significant bits (MSB).
Channel number replaces the 'n' character?
All other characters, like space or comma, are ignored and can be used as separator.

MIDI value
 Number of bits
Written as

Let's take an example :
On my Roland JV-30 synthesizer manual, I read a specific command, part of the NRPN (Non-registered parameter number) section, can be used to manage the internal filer cutoff frequency. Values for this command can be in a range from de 0 to 127.

I open the configuration box from the curve pop-up menu, and select the first MIDI parameter curve. I enter the minimum (0) and maximum (127) valuer. The value will therefore be represented in the command text by 'll'.
I input the command text "Bn 63 01 Bn 62 20 Bn 06 ll" (by refering to the synthesizer manual)
I just have now to draw the curve shape to send commands to my synthesizer. Character 'n' will be substituted by the channel number, and 'll' by the value that has been read on the curve.

Note :
Coherence of the command string is not checked by the program.
You are therefore responsible to ensure it matches the indications in your synthesizer manual.

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