BK-12M   Floorstanding as in Hobby Hifi 6/2016

Technical data
  • impedance: 8 Ohm
  • sensivity (2,83V/1m): 92 dB
  • size (HxWxD): 810 x 190 x 380 mm
  • frequency range (-8dB): 70 - 18000 Hz
  • crossover frequency(s): Hz
  • speaker type: de bocina

BK-12m and BK-12m-Sol are two small floorstanding horn speakers with Fostex fullrange speakers.

BK12M has been developed by Bernd Timmermanns, Madisound USA and Günter Damde.

The speaker is built as a backloaded horn.

The crossover contains two wave traps in series to the speaker.

Between 200 Hz and 10 kHz, the frequency response of this loudspeaker is nearly smooth on axis. The decay spectrum is nearly without faults. At low volume, i.e. 90 dB at 1 m, the nonlinear distortions are below 1% above 200 Hz.

Our kit consists of

  • Fostex FE 126EN, 12cm, full range, 8 Ohm
  • 3x Damping fleece MT Bondum 800 (30 x 50 x 2 cm)
  • Damping Sonofil 100 x 35 cm for 20 litres
  • Binding Post PK31, gold plated (one pair, red and black)
  • 2m Speaker cable 2x2.5 mm2, transparent
  • 0,5x Pan screws 4x20 black, cross recess, 8 pieces
  • Plan for DIY kit

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

  • Audaphon MKP CAP Superior 2.2 uF / 400 Vdc
  • Mundorf, electrolytic capacitor, unetched, 33uF / 70 Vdc
  • 1.0 mm air core coil, 0.22 mH/0.21 Ohm
  • 1.0 mm air core coil, 0.47 mH/0.32 Ohm
  • Metal-oxide resistor, 10W 6.8 Ohm (blue-grey-gold)
  • Metal-oxide resistor, 10W 18 Ohm (brown-grey-black)

Kit without cabinet, price per speaker   EUR 114,00 excl. VAT: € 95.80 / $ 108.25

Kit with high-end crossover

The high-end kit comes with Mundorf MCAO EVO oil capacitors and Mundorf baked varnish air core coils which minimize the 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.

Kit with high-end-crossover without cabinet, price per speaker   EUR 168,00 excl. VAT: € 141.18 / $ 159.53

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).


Price per impedance correction for one speaker, to be mounted on a small wooden board.     EUR 6,90 excl. VAT: € 5.80 / $ 6.55

universal PCBs

If you prefer to mount the crossover components on a 159 x 127 mm universal PCB instead on wood:
Universal PCB RA160, order no.. I-2766, price per unit:   EUR 5,10 excl. VAT: € 4.29 / $ 4.84
We recommend one board per kit (two boards for a speaker pair)


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