Напольная акустика — Blumenhofer Acoustics 40th Anniversary

The 40ies Anniversary is a horn loudspeaker that Blumenhofer Acoustics of Germany built to celebrate the company's 40th birthday. It appears in the maker's R&D section next to three other large projects, the Wiki, the Concert X and the DV-3, and Blumenhofer states that it would be offered only once, as a collector edition. Announcing it, the company called the model an absolutely special jewel and a surprise. The goal of the project was higher efficiency, and the company describes experimenting with possible configurations to reach it.

Key specs that matter

Two ways are used. A compression driver with a 2 inch horn throat and a 100 mm beryllium membrane handles the range above the crossover, while two 380 mm paper woofers take the bass. The crossover is external and divides the band at 850 Hz. Blumenhofer quotes 30 Hz to 20 kHz within plus or minus 2 dB, while adding that it considers a single frequency figure unable to show the full potential of such a speaker. Efficiency is 100 dB, impedance is 8 ohm and maximum power input is 150 W RMS. Each speaker weighs 180 kg.

Engineering and use context

Panels are 25 mm birch plywood in a modular construction with a highly complex structure, and the internal bracing is designed as a structural interaction between them. In the bass section the reflex port opens toward the floor. Time alignment between the two drivers is part of the design, and impedance linearisation keeps the load curve flat. Adjustable spikes form the feet of each cabinet, allowing it to be levelled on the floor. Within the R&D group it differs from the Wiki, which uses one 380 mm woofer in a bass horn, from the Concert X, which places a horn in an open baffle, and from the DV-3, whose bass horn can take two to six woofers. Blumenhofer offers real wood veneers from its own workshop, pointing out that differences in colour and grain are natural to wood and not a defect. The warranty runs for 10 years.

Pairing

Blumenhofer lists the 40ies Anniversary as tube friendly, and the combination of a flat load with high efficiency suits low-power valve amplifiers. Gold-plated tellurium copper binding posts support bi-wiring and bi-amping, so the woofer pair and the horn section can each receive their own amplifier channel.

Alternatives

The Wiki from the same R&D section is a two-way horn design rated at 103 dB, with an 800 Hz crossover and a weight of 300 kg.