The time taken for a sound to achieve maximum amplitude. Drums have a fast attack, whereas bowed strings have a slow attack. In compressors and gates, the attack time equates to how quickly the processor can change its gain....
2500 Modular Unveiled in 1970 under the name, Tonus, Inc., this was ARP's first synthesizer. Modular in design, it uses [color-coded] sliders for patching, doing away with other modulars' messy cords. However, the sliders introduced problems with cross-talk. [Where patch cords are necessary, and they are for some things, the 2600 uses mini-jacks, not 1/4-inch] It was available in custom configurations.
Along with Philip Dodds [ARP vice-president of engineering], the 2500 made a cameo appearance in Close Encounters of the Third Kind (1977,1980), where it helped man communicate with the visitors from outer space through music and mathematics.