controllers designed to control its own virtual instrument software. Auxiliary controllers Software synthesizers offer great power and versatility, but some players feel that division of attention between a MIDI keyboard and a computer keyboard and mouse robs some of the immediacy from the playing experience. Devices dedicated to real-time MIDI control provide an ergonomic benefit and can provide a greater sense of connection with the instrument than can an interface that is accessed through a mouse and computer keyboard. Controllers may be general-purpose devices that are designed to work with a variety of equipment, or they may be designed to work with a specific piece of software. Examples of the latter include Akai's APC40 controller or Nakedboards MC-8 for Ableton Live, and Korg's MS-20ic controller which is a reproduction of their MS-20 analog synthesizer. The MS-20ic controller includes patch cables that can be used to control signal routing in their virtual reproduction of the MS-20 synthesizer and can also control third-party devices. Control surfaces Control surfaces are hardware devices that provide a variety of controls that transmit real-time controller messages. These enable software instruments to be programmed without the discomfort of excessive mouse movements, or adjustment of hardware devices without the need to step through layered menus. Buttons, sliders, and knobs are the most common controllers provided, but rotary encoders, transport controls, joysticks, ribbon controllers, vector touchpads in the style of Korg's Kaoss pad, and optical controllers such as Roland's D-Beam may also be present. Control surfaces may be used for mixing, sequencer automation, turntablism, and lighting control. Specialized real-time controllers Audio control surfaces often resemble mixing consoles in appearance, and enable a level of hands-on control for changing parameters such as sound levels and effects applied to individual tracks of a multitrack recording or channels supporting a live performance. MIDI footswitches are commonly used to send MIDI program change commands to effects devices but may be combined with a pedalboard for more detailed adjustment of effects units. Pedals are available in the form of on/off switches, either momentary or latching or as expression pedals whose position determines the value of a MIDI continuous controller. Drawbar controllers are for use with MIDI and virtual organs. Along with a set of drawbars for timbre control, they may provide controls for standard organ effects such as Leslie speaker speed, vibrato and chorus. Use in a data stream Modifiers such as modulation wheels,