Here's a well-maintained example of a Leslie 147A, flanked by two Hammond organs. Note the Leslie cabinet's three chambers. In the upper chamber is the rotating tweeter horn assembly. One of the two horns is a plugged fake provided for mechanical balance only. The middle chamber serves as a ported speaker baffle with the port being the diagonal slice at the right of the woofer mounting board. Notice the upper and lower motor sets and control relays, the upward-firing tweeter (directly below the horn), and the fifteen-inch downward-firing woofer. In the bottom chamber, the rotor is on the right, with the "vane," which projects the woofer's sound, facing to the right-front. The amplifier chassis is on the left. The Leslie really is a complex electro-mechanical device.