Altec 511E

The Altec 511E is a 1-inch exponential sectoral horn, part of Altec's long-running 511 horn family. It's the screw-on (threaded) sibling to the more common 511B, which used a two-bolt mounting arrangement. The 511E was meant for drivers that thread directly onto the horn throat. The horn is a two-piece die-cast aluminum design finished in gray, with a 500 Hz cutoff.

The documented specs are thin but consistent across sources. It's an 8-ohm horn rated at 30 watts, with a frequency response of 500-12,000 Hz and a weight of 8.5 kg. Dimensions are listed as 62 × 49 × 49 cm. The 802 series drivers are cited as compatible with the standard 511E horn. The record disagrees on coverage angle. One source says 80° × 40°, another 90° × 40°, but that second source covers both the 511B and 511E together, so the figures may be conflated. The angle is left out here rather than guessed. Altec's advertising from the period emphasized the brand's precision craftsmanship and devotion to quality in its components Audio (August 1960, p.39).

No production years, original price, or period reviews have surfaced. The 511E appears in Altec's own bulletin literature as a "1" exponential sectoral horn," and it's still bought and sold in pairs on the used market today.

- Horn type: 1" exponential sectoral, two-piece die-cast aluminum

- Driver mounting: threaded (screw-on)

- Frequency response: 500–12,000 Hz

- Impedance: 8 ohms

- Power handling: 30 W

- Weight: 8.5 kg

- Dimensions: 62 × 49 × 49 cm