Напольная акустика — Blumenhofer Acoustics Corona 4x180 P2C

The Corona 4x180 P2C is the higher-rated of two versions of the Corona 4x180 floorstander from Blumenhofer Acoustics, a German maker of horn loudspeakers that has made hi-fi products since 1977. Its sibling, the Corona 4x180 P, has the same cabinet and horn but conventional paper woofers, while the P2C gets Peek-Carbon sandwich cones and a higher power rating. Blumenhofer describes the Corona 4x180 as a two-way box that has been boosted, built to carry speed, horn loading and power into a better-looking outfit, and says the design gathers all the technologies the firm had developed in recent years.

Key specs that matter

Four 6.5 inch (17 cm) woofers with P2C Peek-Carbon sandwich membranes handle the range below 1000 Hz. Higher frequencies go to a compression driver with a 1.4 inch horn throat and a 3 inch (75 mm) titanium membrane. The maker quotes 36 Hz to 20 kHz within plus or minus 2 dB. Cabinet dimensions are 425 x 605 x 1190 mm, and a single speaker weighs 50 kg, the same as the paper-cone P.

Engineering and use context

Blumenhofer explains that the P2F and P2C membrane structures came from a cooperation with ATE in Ulm and were developed alongside the complete bass driver unit, which Ehman and Partner in Gundelsheim then assembled. The cabinet uses 18 mm birch plywood with interacting structural braces, and a dedicated compartment isolates the crossover from the bass volume. Low frequencies are vented through a harmonic bass reflex port that exits at the front, behind the horn. Under the harmonic construction principle the walls are set at non-parallel angles to fight standing waves, and every panel is tuned to its own resonance so that excess energy is distributed over a chosen band rather than suppressed by heavy damping. Blumenhofer also lists waveformer technology and time alignment of the drivers. The speaker stands on adjustable spikes, can be finished in true-wood veneer from the Blumenhofer workshop, and comes with five years of warranty.

Pairing

The maker rates efficiency at 94 dB and nominal impedance at 4 ohm, and the P2C can take up to 300 W RMS. For valve amplifiers the crossover includes an impedance linearisation that can be switched out, since some owners prefer to run without it depending on taste and the overall system, and the terminal panel supports bi-amping.

Alternatives

The Blumenhofer Corona 4x180 P uses the identical cabinet, horn and compression driver with plain paper woofers and a maximum input of 250 W RMS.