Since its introduction in 1955, the Hammond B3 organ has become a mainstay of music genres ranging from jazz to blues to gospel to rock. Hammond stopped building B3s in 1974, and a B3 in good condition fetches several thousand dollars. Now you can turn your Mac into a B3 with Native Instruments’ B4. This software synthesizer uses sophisticated modeling techniques to re-create the B3’s distinctive, beefy sound — complete with rotating Leslie speaker — with astonishing accuracy. Better still, you can control every sound parameter from a MIDI sequencer program or hardware controller. You can also tweak sounds in real time using B4’s true-to-life interface.