Напольная акустика — Blumenhofer Acoustics Concert X

The Concert X is a two-way horn loudspeaker from Blumenhofer Acoustics, the company Thomas Blumenhofer started in 1977 and still runs from a site in the Augsburg Western Forests nature park, not far from Munich in southern Germany, and which has built horn loudspeakers for more than 40 years. Its in-house techniques include Bass Horn, Floor Effect and Impedance Linearization. It sits in the Research and Development line next to the Wiki and the modular DV-3x16. Work on it began in 2014, when the company set out to build larger loudspeakers and to learn how two 16-inch woofers could be combined inside one horn.

Key specs that matter

Treble and midrange come from a 2-inch compression driver with a beryllium diaphragm loaded by a front horn. Below 800 Hz the signal goes to a pair of 38 cm (16-inch) paper-cone woofers. Blumenhofer rates the range at 30 Hz to 20 kHz within 2 dB and the sensitivity at 103 dB. Nominal impedance is 8 ohm, and the maker describes the impedance curve as flat. Maximum input is 150 W RMS. Each loudspeaker weighs 300 kg, and the warranty runs for 10 years.

Engineering and use context

The lower section is an open baffle combined with a bass horn. A face plug placed ahead of the woofers raises the compression factor before the horn mouth, and an air flow duct is part of the layout. Because the baffle is open, the mid-bass part radiates to the front and the rear as a dipole, which the company chose to raise the speed of that part of the design. The front horn is built from 25 mm birch plywood, and the bass horn geometry was shaped for low resonance and smooth air flow. The crossover network is housed outside the cabinet as a separate unit. The drivers are arranged for time alignment between the compression driver and the woofers. The company calls the construction modular and highly complex. Adjustable spike feet level the enclosure on uneven floors, and the cabinets are finished in real wood veneer, so grain and colour vary from pair to pair.

Pairing

Given its high efficiency and even load, the maker lists the Concert X as tube friendly, so modest tube amplifiers are a practical match. Separate gold-plated tellurium copper terminals for the horn and the woofers allow bi-amping, with one stereo amplifier for the compression drivers and another for the woofers. In that arrangement a preamplifier with two sets of outputs, or a splitter, drives both amplifiers.

Alternatives

The Blumenhofer Acoustics DV-3 in the same line uses a 2-inch beryllium compression driver with between two and six 16-inch woofers, giving 4 to 16 ohm depending on the configuration.