Sonora   Shelf speaker as in K+T 2/2020

Technical data
  • impedance: 8 Ohm
  • sensivity (2,83V/1m): 84 dB
  • size (HxWxD): 340 x 220 x 315 mm
  • frequency range (-8dB): 48 - 22000 Hz
  • crossover frequency(s): 3300 Hz
  • speaker type: closed box

Sonora is a two way compact speaker.

Sonora is a closed-cabinet loudspeaker with drivers of Monacor .

The kit is delivered with the following drivers:
- a Monacor RBT-1000 tweeter
- a Monacor SPH-175HQ woofer

The loudspeaker has been developed by Thomas Schmidt and Dirk Janssen.

The crossover consists of:
- a 3rd order high-pass filter (18 dB per octave slope) for the tweeter.
- 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 low volume, i.e. 85 dB at 1 m, the nonlinear distortions are below 0,9% above 200 Hz and doesn't exceed 2,1% at 95 dB at 1 m between 300 and 15000 Hz.

Our kit consists of

  • RBT-1000
  • SPH-175HQ
  • PE sealing tape, 5x2 mm, 7.5 m
  • Damping Sonofil 100 x 35 cm for 20 litres
  • 0,5x Foam N25, 100x50x4 cm, black
  • Binding Post PK31, gold plated (one pair, red and black)
  • 2m Speaker cable 2x1.5 mm2, transparent
  • 1,5x 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 3.3 μF; / 400 Vdc
  • Audaphon MKT CAP 4.7 μF; / 160 Vdc
  • Mundorf air core coil L140, 2.2 mH/0.46 Ohm
  • 0.7 mm air core coil, 0.39 mH/0.49 Ohm
  • Metal-oxide resistor, 10W 1.2 Ohm (brown-red-gold)
  • 2x Metal-oxide resistor, 10W 1.5 Ohm (brown-green-gold)
  • Metal-oxide resistor, 10W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 241,75 excl. VAT: € 208.41 / $ 243.83

Kit with high-end crossover

The high-end kit is delivered with baked varnish air core coils 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 Monacor RBT-1000 are of type polypropylen (MKP) Clarity-Cap ESA 250 V.

  • ClarityCap ESA capacitor 2.2 μF; / 250 Vdc
  • ClarityCap ESA capacitor 3.3 μF; / 250 Vdc
  • Audaphon MKP CAP Superior 4.7 μF; / 400 Vdc
  • Mundorf baked varnish air core coil BL71, 0.39 mH/0.51 Ohm
  • Mundorf baked varnish air core coil BL140, 2.2 mH/0.46 Ohm
  • Metal-oxide resistor, 10W 1.2 Ohm (brown-red-gold)
  • 2x Metal-oxide resistor, 10W 1.5 Ohm (brown-green-gold)
  • Metal-oxide resistor, 10W 15 Ohm (brown-green-black)

Kit with high-end-crossover without cabinet, price per speaker   EUR 258,32 excl. VAT: € 222.69 / $ 260.55

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).

  • JB, electrolytic capacitor, bipolar advanced, 22μF / 100 Vdc
  • 0.7 mm air core coil, 0.33 mH/0.48 Ohm
  • ceramic resistor 10 Ohm/20 Watt

Price per impedance correction for one speaker, to be mounted on a small wooden board.     EUR 9,07 excl. VAT: € 7.82 / $ 9.15

universal PCB

If you prefer to mount the crossover components on a universal PCB instead on wood
PCB 150x115 mm, tin plated, price per unit:   EUR 4,58 excl. VAT: € 3.95 / $ 4.62
We recommend one board per kit (2 boards per speaker pair)


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