-XG vs. GM-
2. Voice Editing
3. Effects
The XG format has three effect groups:
Each of these three groups includes several individual effect types. The reverb groups features hall, room, and other reverb effects, while the chorus group has chorus, flanger, and other related effects. The variation group includes variations of the reverb and chorus effects as well as rotary speaker, tremolo, amp simulator, auto-wah, distortion, and more. For even further flexibility the variation effects can be inserted into a single channel or used as an overall system effect.
[XG Studio Image diagram]
4. External Inputs
Specifically, XG offers the following four main advantages over GM:
XG fully supprts and expands on the broad applicability and compatibility of MIDI and GM, providing significantly enhanced expressive control and versatility.
1. Number of Voices
Simply, the MSB is used to specify whether a melody voice, SFX voice, or rhythm voice is to be selected. This also allows channels other than "10" to be used for rhythm. The LSB is used to select melody voice variations.
If MSB "7F" is specified on a melody channel, that channel can be used to play a rhythm part. "7E" provides access to a range of sound effects - each key on the keyboard plays a different sound effect. The default channel settings are: channel 10 is rhythm, and all others are set to bank select MSB "0" (the GM sound set).
If a nonexistent voice is specified on an XG tone generator, that part wil be played by an appropriate GM voice. If, however, the MSB specifies an SFX voice or kit and the specified voice or kit is not available, no sound will be produced - a little caution is necessary in this area.
GM tone generators allow the sound of the 128 voices to be modified through modulation, main volume, pan, expression, sustain, RPN , and similar parameters. All of these are "superficial" parameters, not the kind of true voice editing parameters that serious music production requires. XG tone generators provide all of the same parameters, plus an additional range of parameters that allow the actual sound of the voices to be changed in many ways. For example, it is possible to brighten up the sound of a piano, or program a slower attack for a strings voice. The XG format provides a wide range of voice parameters via MIDI control change messages, allowing easy, in-depth voice editing.
In MIDI, a number of control change numbers are already assigned to voice editing parameters: brightness, harmonic content, attack time, release time, and more. In the XG format these assignments are re-interpreted for practical use: for example, "brightness" controls filter cutoff frequency, "harmonic content" controls resonance, and so on. The NRPN numbers - a range of unassigned control change numbers provided for individual manufacturer use - are additionally assigned for even finer control.
Thus the XG format allows detailed control. Further, drum editing is facilitated by allowing the filter cutoff frequency, resonance, EG attack, etc., of each drum instrument - snare, kick, etc. - to be edited individually.
As one example of the subtle nuances that can be controlled with XG, consider the dynamics of an acoustic instrument. The harmonic spectrum of the sound is different when the instrument is struck, plucked, or otherwise played hard or soft. This effect is simulated in the XG format by using a low-pass filter, achieving a new level of musicality and presence.
The XG format provides a remarkable sophisticated system of effects and effect control. More than just the basics, XG makes it possible, for example, to change reverb types and precisely control reverb time. Flanger, phaser, and distortion effects are also provided for exceptionally versatile creative sound control. Some models even feature a graphic equalizer for flexible response shaping.
The three effect groups can be used simultaneously, and parameters can be varied in real time for extraordinary expressive potential.
Some models also feature a graphic equalizer for overall response shaping. In addition to a number of presets designed for specific musical genres - rock, pops, classic, etc. - the EQ bands can be individually set as required for pinpoint sound shaping precision.
XG offers more than just music data playback. External audio input allows user participation as well. The audio signal is processed via the internal digital mixer, and can be controlled to some degree in the same way as the tone generator. Effects, for exameple, can be fully applied to the external audio signal.
One possible application is to connect a microphone and mix the microphone sound with that of MIDI playback for state-of-the-art "karaoke" enjoyment. Of course, it's just as easy to connect an electric guitar, bass, or keyboard and mix the sound of the instrument with MIDI playback for minus-one practice. The XG distortion and amp simulator effects can be applied to a guitar signal for top-quality sound. There are also endless possibilities for live performance.
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