Micro Block   Shelf speaker as in Hobby Hifi 2/2015

Technical data
  • impedance: 6 Ohm
  • sensivity (2,83V/1m): 82 dB
  • size (HxWxD): 350 x 150 x 310 mm
  • frequency range (-8dB): 40 - 34000 Hz
  • crossover frequency(s): 1200 Hz
  • speaker type: bass reflex

The Micro-Block is a compact loudspeaker with extremely well-behaved sound dispersion and other very good sonic properties at a low price. Bernd Timmermanns has developed this bass reflex speaker. The Micro-Block is home to a Wavecor dome, the TW030WA12, and the subwoofer SW118WA02.

We warmly recommend this loudspeaker.

Its crossover consists of a low-pass and a high-pass branch each of second order, i.e. with a slope of 12 dB per octave. A resistor sits in series to the tweeter as a voltage divider. To give a slight lifting to the highest treble, a capacitor is wired parallel to that resistor. No components were needed for eliminating any resonances or bulges in the frequency response.

We see a very even on-axis frequency response from 30 Hz to 30,000 Hz. The decay spectrum (waterfall diagram over frequency) is exemplary, free of any disturbing resonance. At 90 dB and 1 m, non-linear distortions remain below 0.4 % almost everywhere above 200 Hz.

An excerpt from the Hobby HiFi review

Conclusion of the magazine Hobby HiFi:

Our kit consists of

  • Wavecor silk dome tweeter TW030WA12, 8 Ohm
  • Wavecor Subwoofer SW118WA02, 8 Ohm
  • Bass reflex tube HP50, 50x143mm, black
  • Damping fleece MT Bondum 800 (30 x 50 x 2 cm)
  • Binding Post PK31, gold plated (one pair, red and black)
  • 2m Speaker cable 2x2.5 mm2, transparent
  • Pan screws 4x20 black, cross recess, 8 pieces
  • Plan for DIY kit

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

  • Mundorf MCAP EVO Oil 6.8 μF / 450 V
  • Mundorf MKP capacitor 33 μF / 250 V
  • Audaphon MKP CAP Superior 1.0 μF / 400 Vdc
  • Mundorf baked varnish air core coil BL71, 1.5 mH/1.13 Ohm
  • Mundorf baked varnish air core coil BL140, 2.2 mH/0.46 Ohm
  • Metal-oxide resistor, 10W 8.2 Ohm (grey-red-gold)
  • Metal-oxide resistor, 5W 6.8 Ohm (blue-grey-gold)

Kit without cabinet, price per speaker   EUR 366,00 excl. VAT: € 307.56 / $ 353.70

Kit with high-end crossover

The high-end kit contains Mundorf MCAP EVO capacitors of which 2 are Silver Gold Oil capacitors. The coils are a Mundorf Hepta coil and a baked varnish coil for diminishing the microphonics effect. Current flowing through the coil creates a magnetic field which on itself sets the reel of wire in motion. That motion induces a voltage in the coil which adds itself to the original signal.

Kit with high-end-crossover without cabinet, price per speaker   EUR 539,00 excl. VAT: € 452.94 / $ 520.88

Impedance correction

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

  • Mundorf MKP capacitor 6.8 μF / 400 V
  • Audaphon MKP CAP Superior 15 μF / 400 Vdc
  • Mundorf baked varnish air core coil BL71, 0.10 mH/0.23 Ohm
  • Mundorf baked varnish air core coil BL71, 1.5 mH/1.13 Ohm
  • Metal-oxide resistor, 10W 18 Ohm (brown-grey-black)
  • Metal-oxide resistor, 10W 22 Ohm (red-red-black)
  • Metal-oxide resistor, 10W 27 Ohm (red-purple-black)
  • Metal-oxide resistor, 10W 33 Ohm (orange-orange-black)


Price per impedance correction for one speaker, to be mounted on a small wooden board.     EUR 42,00 excl. VAT: € 35.29 / $ 40.59

universal PCB

If you prefer to mount the crossover components on a 159 x 127 mm universal PCB instead on wood:
Universal PCB RA160, order no.. str-RA160, price per unit:   EUR 5,90 excl. VAT: € 4.96 / $ 5.70
We recommend one board per kit (two boards for a speaker pair)


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