DigiBox 87HP   Shelf speaker as in Hobby Hifi 5/2016

Technical data
  • impedance: 4 Ohm
  • sensivity (2,83V/1m): 85 dB
  • size (HxWxD): 242 x 150 x 190 mm
  • frequency range (-8dB): 100 - 20000 Hz
  • crossover frequency(s): Hz
  • speaker type: closed box

Digibox 87 HP is a very small loudspeaker that employs a Visaton SL87 FE fullrange driver.

Digibox 87 HP has been developed by Bernd Timmermanns.

The speaker is built in a closed cabinet with a high-pass filter with different crossover frequencies to harmonize perfectly with a subwoofer.

The crossover consists of two RCL filters in series, one serial RCL and a 2nd order high pass filter (12dB per octave slope).

Between 300 Hz and 6 kHz, the frequency response of this loudspeaker is linear on axis. The decay spectrum is nearly perfect. At low volume, i.e. 90 dB at 1 m, the nonlinear distortions are below 1% above 400 Hz.

Digibox 87 HP with different high-pass filters

We deliver Digibox 87 HP with different cut-off frequencies to adopt it to a subwoofer. If you don't want to use a subwoofer, we recommend the the DIY kit Digibox 87 without high-pass filter.

Our 130 Hz kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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.

  • electrolytic capacitor, etched, 220 μF/63 Vdc
  • electrolytic capacitor, unetched, 1.5 μF / 70 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 6.8 μF / 70 Vdc
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 0.12 mH/0.29 Ohm
  • 0.7 mm air core coil, 0.47 mH/0.50 Ohm
  • Metal-oxide resistor, 10W 2.7 Ohm (red-purple-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 74,70 excl. VAT: € 62.77 / $ 65.91

Our 140 Hz kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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.

  • electrolytic capacitor, etched, 180 μF/63 Vdc
  • electrolytic capacitor, unetched, 1.5 μF / 70 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 6.8 μF / 70 Vdc
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 0.12 mH/0.29 Ohm
  • 0.7 mm air core coil, 0.47 mH/0.50 Ohm
  • Metal-oxide resistor, 10W 1.8 Ohm (brown-grey-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 76,40 excl. VAT: € 64.20 / $ 67.41

Our 150 Hz kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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.

  • electrolytic capacitor, etched, 150 μF/63 Vdc
  • electrolytic capacitor, unetched, 1.5 μF / 70 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 6.8 μF / 70 Vdc
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 0.12 mH/0.29 Ohm
  • 0.7 mm air core coil, 0.47 mH/0.50 Ohm
  • Metal-oxide resistor, 10W 1.0 Ohm (brown-black-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 74,60 excl. VAT: € 62.69 / $ 65.82

Our 160 Hz kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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.

  • electrolytic capacitor, etched, 22 μF/100 Vdc
  • electrolytic capacitor, etched, 100 μF/100 Vdc
  • electrolytic capacitor, unetched, 1.5 μF / 70 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 6.8 μF / 70 Vdc
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 0.12 mH/0.29 Ohm
  • 0.7 mm air core coil, 0.47 mH/0.50 Ohm
  • Metal-oxide resistor, 10W 0.39 Ohm 5% (orange-white-silver)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 79,60 excl. VAT: € 66.89 / $ 70.24

Our 170 Hz kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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.

  • electrolytic capacitor, etched, 100 μF/100 Vdc
  • electrolytic capacitor, unetched, 1.5 μF / 70 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 6.8 μF / 70 Vdc
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 0.12 mH/0.29 Ohm
  • 0.7 mm air core coil, 0.47 mH/0.50 Ohm
  • 0.7 mm air core coil, 3.3 mH/1.75 Ohm
  • Metal-oxide resistor, 10W 1.2 Ohm (brown-red-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 81,70 excl. VAT: € 68.66 / $ 72.09

Our 180 Hz kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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.

  • electrolytic capacitor, etched, 82 μF/100 Vdc
  • electrolytic capacitor, unetched, 1.5 μF / 70 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 6.8 μF / 70 Vdc
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 0.12 mH/0.29 Ohm
  • 0.7 mm air core coil, 0.47 mH/0.50 Ohm
  • 0.7 mm air core coil, 3.3 mH/1.75 Ohm
  • Metal-oxide resistor, 10W 0.68 Ohm 5% (blue-grey-silver)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 81,70 excl. VAT: € 68.66 / $ 72.09

Kit with high-end crossover

The high-end kit comes with two polypropylen capacitors (MKP) and two baked varnish coils in the serial RCL. 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.

Our 130 Hz high-end kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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 1.5 μF / 400 Vdc
  • Audaphon MKP CAP Superior 6.8 μF / 400 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 22uF / 70 Vdc
  • 2x electrolytic capacitor, unetched, 100uF / 50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.12 mH/0.25 Ohm
  • Mundorf baked varnish air core coil BL71, 0.47 mH/0.57 Ohm
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • Metal-oxide resistor, 10W 2.7 Ohm (red-purple-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   - not available

Our 140 Hz high-end kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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 1.5 μF / 400 Vdc
  • Audaphon MKP CAP Superior 6.8 μF / 400 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 82uF / 50 Vdc
  • electrolytic capacitor, unetched, 100uF / 50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.12 mH/0.25 Ohm
  • Mundorf baked varnish air core coil BL71, 0.47 mH/0.57 Ohm
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • Metal-oxide resistor, 10W 1.8 Ohm (brown-grey-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 111,00 excl. VAT: € 93.28 / $ 97.94

Our 150 Hz high-end kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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 1.5 μF / 400 Vdc
  • Audaphon MKP CAP Superior 6.8 μF / 400 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 68uF / 50 Vdc
  • electrolytic capacitor, unetched, 82uF / 50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.12 mH/0.25 Ohm
  • Mundorf baked varnish air core coil BL71, 0.47 mH/0.57 Ohm
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • Metal-oxide resistor, 10W 1.0 Ohm (brown-black-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 106,00 excl. VAT: € 89.08 / $ 93.53

Our 160 Hz high-end kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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 1.5 μF / 400 Vdc
  • Audaphon MKP CAP Superior 6.8 μF / 400 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 22uF / 70 Vdc
  • electrolytic capacitor, unetched, 100uF / 50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.12 mH/0.25 Ohm
  • Mundorf baked varnish air core coil BL71, 0.47 mH/0.57 Ohm
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • Metal-oxide resistor, 10W 0.39 Ohm 5% (orange-white-silver)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   - not available

Our 170 Hz high-end kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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 1.5 μF / 400 Vdc
  • Audaphon MKP CAP Superior 6.8 μF / 400 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 100uF / 50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.12 mH/0.25 Ohm
  • Mundorf baked varnish air core coil BL71, 0.47 mH/0.57 Ohm
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 3.3 mH/1.75 Ohm
  • Metal-oxide resistor, 10W 1.2 Ohm (brown-red-gold)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 115,00 excl. VAT: € 96.64 / $ 101.47

Our 180 Hz high-end kit consists of

  • Visaton SL87 FE, 8 Ohm
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Female banana jacks, red and black
  • 1m Speaker cable 2x0.75 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 1.5 μF / 400 Vdc
  • Audaphon MKP CAP Superior 6.8 μF / 400 Vdc
  • electrolytic capacitor, unetched, 5.6 μF / 70 Vdc
  • electrolytic capacitor, unetched, 82uF / 50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.12 mH/0.25 Ohm
  • Mundorf baked varnish air core coil BL71, 0.47 mH/0.57 Ohm
  • Mundorf air core coil L50, 3.3 mH/3.13 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • 0.7 mm air core coil, 3.3 mH/1.75 Ohm
  • Metal-oxide resistor, 10W 0.68 Ohm 5% (blue-grey-silver)
  • Metal-oxide resistor, 3W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 3W 10 Ohm (brown-black-black)
  • Metal-oxide resistor, 3W 15 Ohm (brown-green-black)

Kit without cabinet, price per speaker   EUR 112,00 excl. VAT: € 94.12 / $ 98.82

universal PCBs

If you prefer to mount the crossover components on a 140 x 102 mm universal PCB instead on wood:
Universal PCB RA140, order no.. str-RA140, price per unit:   EUR 4,20 excl. VAT: € 3.53 / $ 3.71
We recommend one board per kit (two boards for a speaker pair)


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