A sampler is an electronic or digital musical instrument similar in some respects to a synthesizer, but instead of generating new sounds with filters, it uses sound recordings (or "samples") of real instrument sounds (e.g., a piano, violin or trumpet), excerpts from recorded songs (e.g., a five-second bass guitar riff from a funk song) or other sounds (e.g., sirens and ocean waves). The samples are loaded or recorded by the user or by a manufacturer. These sounds are then played back by means of the sampler program itself, a MIDI keyboard, sequencer or another triggering device (e.g., electronic drums) to perform or compose music. Because these samples are usually stored in digital memory, the information can be quickly accessed.
A sampler is organized into a hierarchy of progressively more complicated data structures. At the bottom lie samples, individual recordings of any sound, recorded at a particular sample rate and resolution. While a common sound to sample is a musical instrument being played (e.g., a pianist playing a piano note or an organist playing a pipe organ), a sample could be any sound, including "non-musical" sounds such as a typewriter clacking or a dog barking. A reference center pitch indicates the actual frequency of the recorded note. Samples may also be "looped" by defining points at which a repeated section of the sample starts and ends, allowing a relatively short sample to play endlessly. In some cases, a "loop crossfade" is indicated, allowing less obvious transitions at the loop point by fading the end of the loop out while fading its beginning in. Keymaps are arranged into instruments. At this level parameters may be added to define how the keymaps are played. Filters can be applied to change the sound-color while low frequency oscillators and envelope generators can shape the amplitude, pitch, filter or other parameters of the sound. Instruments may have multiple layers of keymaps in order to play more than one sample at the same time and each keymap may have a different set of parameters so that the incoming note-events affect each layer differently. For example, two layers may have a different sensitivity to the velocity of the incoming note, altering the resulting timbre according to how hard the note is played. At this level, there are two basic approaches to sampler organization. In a bank approach, each instrument is assigned to a different MIDI channel and multiple banks can be stored to reconfigure the sampler. A different and more powerful approach is to associate each instrument with a patch number or ID so that each MIDI channel can be configured separately by sending controller information on the individual channel.

Q: can you explain the heiarchy
A: A sampler is organized into a hierarchy of progressively more complicated data structures.

Q: so how does have have any exciting points
A: Keymaps are arranged into instruments.

Q: anything else?
A: At this level parameters may be added to define how the keymaps are played.
was this great technology
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