The information in this topic pertains only to applications written in Visual Basic. For C++ applications, see Overview of DirectMusic Objects and Interfaces.

The DirectMusicBand class represents a set of instruments (with their volume, pan, and transposition) mapped to the parts in a piece of music. Band changes determined in a style take place automatically when a segment based on that style is played, but you can also obtain a DirectMusicBand object from a style or from a separate file or resource and create a DirectMusicSegment from it. This segment can then be played to effect program changes.

The DirectMusicCollection class represents a DLS collection. Most applications do not need to work directly with collections because the instrument data is downloaded to the port when a segment is played or when a band is downloaded.

The key differences between a collection and a band are as follows:

• A collection is a group of instruments available for use in the playback of any segment. A band is a group of instruments that actually plays a particular segment.
• Instruments in a collection contain DLS data defining their timbre. Instruments in a band contain no such data, but are linked to instruments in one or more collections.
• An instrument from a collection is not inherently associated with any particular performance channel (PChannel) of a segment. A band assigns the patch number of an instrument to each PChannel in a segment and assigns a voice priority to the channel.
• A collection does not contain any information about how the instruments are to be played. A band contains settings for the volume, pan, and transposition of each instrument.