Midesk   Shelf speaker as in Hobby Hifi 2/2017

Technical data
  • impedance: 6 Ohm
  • sensivity (2,83V/1m): 82 dB
  • size (HxWxD): 250 x 140 x 180 mm
  • frequency range (-8dB): 55 - 19000 Hz
  • crossover frequency(s): Hz
  • speaker type: bass reflex

Midesk is a very small speaker that employs a Mivoc FR 358 N fullrange driver.

Midesk has been developed by Bernd Timmermanns.

The speaker is built in bassreflex technology.

The crossover consists of a highshelf-filter and a RCL curcuit in parallel to the fullrange driver. These are smoothing the frequency response and compensating the baffle step.

Between 70 Hz and 10 kHz, the frequency response of this loudspeaker is nearly linear on axis. The decay spectrum is without fault below 10 kHz. At low volume, i.e. 90 dB at 1 m, the nonlinear distortions are below 1% above 400 Hz.

Our kit consists of

  • full range loudspeaker Mivoc FR 358 N
  • Bass reflex tube HP35, 35x125 mm, black
  • 0,5x PE sealing tape, 5x2 mm, 7.5 m
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Binding Post PK31, gold plated (one pair, red and black)
  • 1m Speaker cable 2x0.75 mm2, transparent
  • 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
  • Mundorf air core coil L50, 0.82 mH/1.29 0hm
  • Mundorf air core coil L50, 4.7 mH/3.777 Ohm
  • Mundorf H core coil H71, 2.2 mH/0.38 0hm
  • Metal-oxide resistor, 5W 1.5 Ohm (brown-green-gold)
  • Metal-oxide resistor, 5W 18 Ohm (brown-grey-black)
  • Metal-oxide resistor, 5W 47 Ohm (yellow-violet-black)

Hint: In addition 10 pcs. of sink screws 4,5 x 50 mm for the front panel and 4 pcs. of screws M4 x 20 mm with nuts for the fullrange driver are needed.

Kit without cabinet, price per speaker   - not available

Kit with high-end crossover

The high-end kit comes with MKP capacitors and uneteched electrolytic capacitors instead of etched capacitors for the fullrange driver. All inductances are baked varnished 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.

Kit with high-end-crossover without cabinet, price per speaker   - not available

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 4,30 excl. VAT: € 3.61 / $ 3.87

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.. str-RA160, price per unit:   EUR 5,90 excl. VAT: € 4.96 / $ 5.31
We recommend one board per kit (two boards for a speaker pair)

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