Monacor Cobra-Horn RBT floorstanding loudspeaker from Hobby HiFi 5/2015

Kit without housing price per speaker

Cobra-Horn RBT is a large floor-standing loudspeaker designed as a hyperbolic back-loaded horn. The horn is driven by the Monacor broadband SP-200X; in the upper frequency range, the Monacor magnetostat RBT-95 SR takes over playback. The kit was designed by Bernd Timmermanns. The crossover consists of a 2nd order low-pass filter (12 dB/octave) for the broadband loudspeaker and a 2nd order high-pass filter (12 dB/octave) for the magnetostat. The frequency response of the loudspeaker is quite linear. The decay spectrum is slightly delayed in the middle. The non-linear distortions are quite low at 90 dB/1m in the low and mid-range and increase to just under 3% from 2 kHz.

Technical data:

• Impedance: 8 Ohm
• Sound pressure level (2.83V/1m): 93 dB
• Dimensions (HxWxD): 1078 x 338 x 500 mm
• Frequency range (-8dB): 50 - 30000 Hz
• Crossover frequency(s): 5000 Hz
• Principle: Horn

Highlights

• Magnetostat tweeter RBT-95SR
• Monacor SP-200 X broadband loudspeaker
• 0.5x PE foam sealing strip, 5x2 mm, roll 7.5 m
• 2.5x Sonofil insulation material 100 x 35 cm for 20 liters
• Pole terminals PK31, one pair, gold-plated, red+black
• 2m speaker cable 2x2.5 mm2, transparent
• Pan screws 4x20 black, Phillips, 8 pieces
• Construction plan for the kit the crossover components (right), to be assembled on a wooden board.
• Audaphon MKP CAP Superior 2.7 μF / 400 Vdc
• Audaphon MKT Capacitor 1.5 μF / 160 Vdc
• 1.0 mm air coil, 0.47 mH/0.32 Ohm
• 0.7 mm air coil, 0.15 mH/0.25 Ohm
• MOX5 resistor 68 Ohm / 5 Watt (blue-gray-black)
• Metal oxide resistor MOX5 0.68 Ohm 5% (blue-gray-silver)
• Metal oxide resistor MOX5 4.7 Ohm (yellow-violet-gold)