Stop the music

The Accompaniment Machine (AMac) is a performance-enhancement program for keyboards (such as the Yamaha PSR E423/E433). One of our goals in developing the program was to include features that greatly expand the capabilities of the digital keyboard. For example, with the program you can…

  • Store unlimited song setups
  • Utilize the extensive set of styles available on the Internet
  • Define new melody voices
  • Use all available sections of a style
  • Shift style sections and perform other function in response to a single control key on the keyboard.
  • Create playlists of MIDI songs available on the Internet
  • Synchronize styles to measures with an irregular number of beats.

In other words, AMac removes all the limitations built into the keyboard.

The program development was also guided by a more fundamental motivation. We were determined that AMac would play accompaniment styles better than the original keyboard. To this end, we have constantly refined the accompaniment engine and added new features since the release of Version 1.0. One area where AMac excels is in graceful song endings. Endings are critical to a good performance. An abrupt style termination destroys the sense of a live backup. The listener immediately senses the machine behind the curtain.

AMac features multiple options for song endings. One of the main drawbacks of the PSR E423 keyboard is that there is no way to accomplish a true fade (i.e., the performance continues but the volume gradually drops). Implementation of fades was one of the main motivations for AMac. The sequence operation

Fade out     7.5

usually appears at the end of a song. Performers can invoke the command by a single press of the control key without removing their hands from the keyboard. As they continue to play, the MIDI volume drops following an inverse raised-cosine function with a length in seconds given by the command parameter. This function smoothly transitions the volume change and ends with a tail that gives performers ample time to remove their fingers from keyboard.

Another way to end a song is with the sequence operation

Stop style     0.8

In this case, performers can stop the style at any chosen point. In this case, the program holds the current style notes and drops the volume with the same procedure as the fade function over an interval given by the time parameter. A gradual stop provides a much better sound that simply sending an AllNotesOff signal. Another application for the Stop style command with fade is repairing style Endings. In styles obtained on the Internet, you may often encounter Ending sections that have a jarring termination. The solution is the operation sequence

Ending C
Stop style 2.5

Here, the performer presses the control key on the last notes of the Ending, AMac holds the notes and applies a fade with a length given by the real-number parameter.

Another option is

Stop downbeat  5.0

The operation is similar to the Stop style command, except that AMac automatically picks the stop time. In this case, the program holds style notes played on the downbeat of the next measure and applies a fade. The Stop downbeat operation makes a great all-purpose ending.

The following musical examples demonstrate the features. This one illustrates stopping variations:

Stop style demonstration

The file contains three short sections. The first stops immediately at a user-chosen point in time (AllNotesOff). The second stops at the same point but applies a fade. The final section illustrates the Stop downbeat option where AMac picks the stopping point. The next example illustrates correction of a style with a bad ending by adding a Stop style command with a fade of a few seconds:

Correcting a bad ending with a Stop style operation


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