Open the tutorial.

The groove~ object is the most versatile object for playing sound from a buffer~. You can specify the buffer~ to read, the starting point, the playback speed (either forward or backward), and starting and ending points for a repeating loop within the sample. As with other objects that read from a buffer~, groove~ accesses the buffer~ remotely, without patch cords, by sharing its name.

In the example above, the message loop 1 turns looping on, the start time of 0 ms indicates the beginning of the buffer~, the playback speed of 1 means to play forward at normal speed, and the loop start and end times mean that (because looping is turned on) when groove~ reaches a point 860 milliseconds into the buffer~ it will return to a point 572 ms into the buffer~ and continue playing from there. Notice that the start time must be received as a float (or int), and the playback speed must be received as a signal. This means the speed can be varied continuously by sending a time- varying signal in the left inlet.

Whenever a new start time is received, groove~ goes immediately to that time in the buffer~ and continues playing from there at the current speed. When groove~ receives the message loop 1 or startloop it goes to the beginning of the loop and begins playing at the current speed. (Note that loop points are ignored when groove~ is playing in reverse, so this does not work when the playback speed is negative.) groove~ stops when it reaches the end of the buffer~ (or the beginning if it's playing backward), or when it receives a speed of 0.

In the tutorial patch, three different buffer~ objects are loaded with AIFF files so that a single groove~ object can switch between various samples instantly (notice that each buffer~ object also contains two additional optional arguments that identify the length of the buffer and the number of channels). The message set, followed by the name of a buffer~, refers groove~ to that new buffer~ immediately. (If groove~ always referred to the same buffer~, and we used read messages to change the contents of the buffer~, some time would be needed to open and load each new file.)

• Click on the preset object to play the samples in different ways.

The first preset just functions as an ‘Off’ button. The next three presets play the three buffer~ objects at normal speed without looping. The rest of the presets demonstrate a variety of sound possibilities using different playback speeds on different excerpts of the buffered files, with or without looping.

• You may want to experiment with your own settings by changing the user interface objects directly.

If you want to create smooth undetectable loops with groove~, you can use the loopinterp message to enable crossfades between the end of a loop and the beginning of the next pass through the loop to smooth out the transition back to the start point (see the groove~ reference page for more information on this message). If the buffer~ contains an AIFF file that has its own loop points -- points established in a separate audio editing program -- there is a way to use those loop points to set the loop points of groove~.

The info~ object can report the loop points of an AIFF file contained in a buffer~, and you can send those loop start and end times directly into groove~. You can also use the the info~ object to find out the length (in milliseconds) of any file you load into a buffer.

The groove~ object is the most versatile way to play sound from a buffer~. You can specify the buffer~ to read, the starting point, the playback speed (either forward or backward), and starting and ending points for a repeating loop within the sample. If the buffer~ contains an AIFF file that has its own pre-established loop points, you can use the info~ object to get those loop times and send them to groove~. The playback speed of groove~ is determined by the value of the signal coming in its left inlet. You can set the current buffer position of groove~ by sending a float time value in the left inlet.