Cumulus Maxx   Floorstanding as in Hobby Hifi 2-3/2023

Technical data
  • impedance: 3 Ohm
  • sensivity (2,83V/1m): 95 dB
  • size (HxWxD): 1050 x 250 x 300 mm
  • frequency range (-8dB): 45 - 28000 Hz
  • crossover frequency(s): 320, 1500 Hz
  • speaker type: bass reflex

Cumulus Maxx is a three way floorstanding speaker.

Cumulus Maxx is a bass-reflex cabinet loudspeaker with drivers of Redcatt .

The kit is delivered with the following drivers:
- a Redcatt CX8.01X8 coaxial driver
- two Redcatt Exclusive 8 woofers

The loudspeaker has been developed by Bernd Timmermanns.

The crossover consists of:
- a 3rd order high-pass filter (18 dB per octave slope) for the tweeter.
- a band pass consisting of a 2nd order high pass filter (12 dB per octave slope) and a 2nd order low-pass filter (12 dB per octave slope) for the mids-woofer.
- a 2nd order low-pass filter (12 dB per octave slope) for the woofer.

The frequency response of this speaker is nearly linear.

The decay spectrum is nearly perfect.

At medium volume, i.e. 90 dB at 1 m, the nonlinear distortions are below 1% above 200 Hz.

An excerpt from the Hobby HiFi review

Conclusion of the magazine Hobby HiFi:

Our kit consists of

  • Redcatt CX8.01X8
  • 2x Redcatt Exclusive 8
  • 0,5x PE sealing tape, 5x2 mm, 7.5 m
  • 1,5x Damping Sonofil 100 x 35 cm for 20 litres
  • 0,5x Audaphon Damping 10, 970 x 470 mm, adhesive
  • Binding Post PK31, gold plated (one pair, red and black)
  • 3m Speaker cable 2x2.5 mm2, transparent
  • 2,5x Pan screws 4x20 black, torx, 8 pieces
  • Plan for DIY kit

the crossover components (right),
to be mounted on a small wooden board.

  • Audaphon MKP CAP Superior 2.2 μF / 400 Vdc
  • Audaphon MKP CAP Superior 8.2 μF / 400 Vdc
  • Audaphon MKT CAP 0.47 μF / 160 Vdc
  • Audaphon MKT CAP 2.2 μF / 160 Vdc
  • Mundorf, electrolytic capacitor, etched, 180 μF/63 Vdc
  • JB, electrolytic capacitor, bipolar, 150 μF/50 Vdc
  • JB, electrolytic capacitor, bipolar, 220 μF/50 Vdc
  • JB, electrolytic capacitor, bipolar advanced, 15μF / 50 Vdc
  • JB, electrolytic capacitor, bipolar advanced, 22μF / 50 Vdc
  • JB, electrolytic capacitor, bipolar advanced, 68μF / 50 Vdc
  • 1.4 mm air core coil 1.8 mH/0.41 Ohm
  • 0.7 mm air core coil, 0.39 mH/0.51 Ohm
  • 2x 0.7 mm air core coil, 0.82 mH/0.89 Ohm
  • Mundorf ferrite core coil P71 10 mH/2.19Ohm
  • Mundorf ferrite core coil P71 12 mH/2.55Ohm
  • Mundorf H core coil H71, 4.7 mH/0.46 0hm
  • Mundorf H core coil H100, 3.3 mH/0.27 0hm
  • Metal-oxide resistor, 5W 1.5 Ohm (brown-green-gold)
  • Metal-oxide resistor, 5W 4.7 Ohm (yellow-violet-gold)
  • Metal-oxide resistor, 5W 5.6 Ohm (green-blue-gold)
  • Metal-oxide resistor, 5W 8.2 Ohm (grey-red-gold)
  • Metal-oxide resistor, 5W 10 Ohm (brown-black-black)

Kit without cabinet, price per speaker   EUR 549,00 excl. VAT: € 461.34 / $ 498.25

Kit with high-end crossover

The high-end kit is delivered with baked varnish air core coils on important parts of the crossover for minimizing microphonic effects. - The current flow through the coil creates a magnetic field which sets the reel of wire in motion. This motion induces a voltage in the coil which adds itself to the signal. The stiffer the reel of wire is, the less the signal will be altered. The capacitors for the Redcatt CX8.01X8 are of type polypropylen (MKP) Mundorf MCAP EVO Öl 450 V.

  • Mundorf MCAP EVO 68 μF / 350 V
  • Mundorf MCAP EVO Oil 2.2 μF / 450 V
  • Mundorf MCAP EVO Oil 8.2 μF / 450 V
  • Audaphon MKP CAP Superior 0.47 μF / 400 Vdc
  • Audaphon MKP CAP Superior 2.2 μF / 400 Vdc
  • Audaphon MKP CAP Superior 15 μF / 400 Vdc
  • Audaphon MKP CAP Superior 22 μF / 400 Vdc
  • Mundorf, electrolytic capacitor, etched, 180 μF/63 Vdc
  • JB, electrolytic capacitor, bipolar, 150 μF/50 Vdc
  • JB, electrolytic capacitor, bipolar, 220 μF/50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.39 mH/0.51 Ohm
  • 2x Mundorf baked varnish air core coil BL71, 0.82 mH/0.89 Ohm
  • Mundorf baked varnish air core coil BL140, 1.8 mH/0.43 Ohm
  • Mundorf baked varnish ferrite core coil BP71 10 mH/2.19Ohm
  • Mundorf baked varnish ferrite core coil BP71 12 mH/2.55Ohm
  • Mundorf bs140 core coil 3.3 mH/0.19Ohm
  • Mundorf H core Hepta Coil LH45, 4,7 mH/0.34 Ohm
  • Metal-oxide resistor, 5W 1.5 Ohm (brown-green-gold)
  • Metal-oxide resistor, 5W 4.7 Ohm (yellow-violet-gold)
  • Metal-oxide resistor, 5W 5.6 Ohm (green-blue-gold)
  • Metal-oxide resistor, 5W 8.2 Ohm (grey-red-gold)
  • Metal-oxide resistor, 5W 10 Ohm (brown-black-black)

Kit with high-end-crossover without cabinet, price per speaker   EUR 754,00 excl. VAT: € 633.61 / $ 684.30

Impedance correction

If you want to use a valve amplifier with this speaker an impedance correction should be employed. In this case the component quality is less important; therefore, we offer only one kit (upon request higher quality components are available).

  • Audaphon MKT CAP 47 μF / 160 Vdc
  • 0.7 mm air core coil, 0.068 mH
  • ceramic resistor 3.9 Ohm/20 Watt

Price per impedance correction for one speaker, to be mounted on a small wooden board.     EUR 17,80 excl. VAT: € 14.96 / $ 16.15

universal PCB

If you prefer to mount the crossover components on a 159 x 127 mm and two 140 x 102 mm universal PCB instead on wood:
Universal PCB RA160, order no.. str-RA160, price per unit:   EUR 5,90 excl. VAT: € 4.96 / $ 5.35
Universal PCB RA140, order no.. str-RA140, price per unit:   EUR 4,20 excl. VAT: € 3.53 / $ 3.81
We recommend one board RA160 and two boards RA140 per kit (four boards RA140 and two boards RA160 for a speaker pair)


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