Altec Lansing 511 Loudspeaker

Name: Altec Lansing 511
Brand: Altec

The Altec Lansing 511 is a four-way loudspeaker system. Period reviews are the main source of information on it. The most detailed one is in Audio (April 1991, p.84). It lists a sealed-box design with two 10-inch woofers, a 6½-inch mid-bass driver, a 2-inch dome midrange and a 1-inch dome tweeter. Crossovers sit at 180 Hz, 1.5 kHz and 3.5 kHz. Rated frequency response is 24 Hz to 20 kHz ±3 dB. Sensitivity is 92 dB SPL at 1 meter for 1 watt, and nominal impedance is 4 ohms. Power handling is 150 watts nominal, 300 watts maximum. The cabinet is 57 inches tall, 13 inches wide and 13½ inches deep, and it weighs 110 pounds.

HiFi-Stereo (November 1989, p.92) tested a sample. On-axis response was reasonably flat, but off-axis it showed a sharp drop in output above the tweeter resonance frequency, measured 45 degrees off the speaker’s axis. The reviewer found the system still sounded balanced and natural on music. There was no audible sign of the tweeter resonance peak, though a slight mid-bass heaviness could occasionally be heard. Beyond these two reviews, little other documentation appears to exist for this model.