A sound buffer is a chunk of memory of any given size which is filled with sound data and manipulated using various DirectSound function calls. In DirectSound, there are different types of buffers including Primary Buffers, Secondary Buffers, Primary Capture buffers and Secondary Capture Buffers.

Primary Buffers are created one per device and are generally used to control the physical input/output of a particular device.
Secondary Buffers are usually created for each individual sound element, and are automatically mixed by DirectSound when played back.