Напольная акустика — Line Magnetic LM-812

The LM-812 is a passive two-way horn loudspeaker from Line Magnetic, modelled on the historic Altec 812 horn system. To recreate that layout, the company combines its own duplicate of the Altec 808-8 horn and driver with an 18 inch bass driver of Line Magnetic design. The maker lists the LM-812 in its retro loudspeaker range next to the LM-69, LM-755A and LM-222 models. Of those neighbours it is the one that splits the band between a large cone woofer and a separate horn sitting above it.

Key specs that matter

The quoted sensitivity is 102 dB, the nominal impedance is 8 ohm and the frequency range runs from 37 Hz to 20 kHz. Line Magnetic gives a power rating of 40 W. Each cabinet measures 720 mm in width, 1180 mm in height and 590 mm in depth. The enclosure is built from multiply wood with a mahogany tint. A pair of screw terminals on each speaker also accepts banana plugs.

Engineering and use context

The upper band is handled by the LM-808 horn, which is loaded by an LM-802B compression chamber, and the low range goes to the BA-18 woofer with a diameter of 46 cm. The horn is a cast part fitted with vernier adjustments that allow it to be fine tuned. Pairing a compression-loaded horn with a large woofer mirrors the two-way division of the Altec original that Line Magnetic set out to copy. Compared with its siblings the efficiency figure is higher, sitting well above the 95 dB of the LM-69 and the 92 dB listed for the LM-755A.

Pairing

With its high sensitivity, the LM-812 can be run from very small valve amplifiers, and Line Magnetic states that it suits all kinds of amplification. The brand's LM-845IA, a single-ended integrated whose two 845 output triodes yield 22 W per channel in Class A, stays comfortably within the speaker's power rating, and its hand-made point-to-point circuit drives output taps for 4, 8 and 16 ohm. The AS-125 is another in-house option, taking 18 W per channel from two 211 valves and using a copy of the Western Electric 618 transformer at the input of its preamplifier stage.

Alternatives

The Line Magnetic LM-222 is a two-way floorstanding alternative that uses a coaxial driver with a six-cell horn inspired by the Jensen 222.