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The portamento effect in a MIDI is realized through the “wheel” function in music editing software such as SONAR. Different “wheel” parameters represent portamentos of different depths. You can draw a wheel event or change the pitch bender of the MIDI keyboard to change the portamento effect.

In most music editing software, the default portamento width is that of two positive-negative semitones, or 4 semitones. When you want a portamento to last for more than 4 semitones, you should change event 0 of RPN code (namely, the Bend pitch event) to adjust the wheel width. The portamento width is calculated in the following formula: Wheel pitch=2*(bend pitch/128)

Suppose you need 4 semitones’ width of portamento, you have 4=2*(bend pitch/128), so the Bend pitch is 256.

In AM4F2.0, a portamento can last for at most 4 semitones since Bend pitch is not supported, while in AM4F2.1 a portamento can last for the same width set in the music editing software (Bend pitch supported).

Setting MIDI portamento in AM4F2.0:

Create the portamento in the MIDI file. AM4F2.0 and AM4F2.1 support multi-channel portamento, that is, different portamentos can be played simultaneously in different channels.

Note:

Make sure to set the portamento parameter to 0 at the end of a portamento, otherwise, all the subsequent notes may raise or reduce by the portamento width.

Multichannel portamento

Add the prepared midi to Ezmusican2.0 for timbre editing. The timbre range you set must accommodate the portamento width, otherwise errors may occur during MIDI play. When possible, always use one patch to simulate the entire range, this can avoid range overflow. When using AM4F2.1 to make portamento longer than 4 semitones, you should set the timbre for the portamento as instrument; otherwise, errors may occur during MIDI play.

Compile the project in Ezmusican2.0 to generate the MDB file and call the MDB file in AM4F_EzCode2.0 for playing the portamento.

Note:

Attached is a demo of the portamento, please use AM4F_V2.1 with it. The program and data are for reference only.