Audimax Bookshelf AMT   Shelf speaker as in Hobby Hifi 6/2021

Technical data
  • impedance: 8 Ohm
  • sensivity (2,83V/1m): 82,5 dB
  • size (HxWxD): 440 x 220 x 340 mm
  • frequency range (-8dB): 38 - 33000 Hz
  • crossover frequency(s): 2500 Hz
  • speaker type: bass reflex

Audimax Bookshelf AMT is a two way compact speaker.

Audimax Bookshelf AMT is a bass-reflex cabinet loudspeaker with drivers of Mundorf and Hobby-HiFi (Made by SEAS).

The kit is delivered with the following drivers:
- a Mundorf AMTU80W1.1 air motion transformer (ribbon-tweeter)
- a Hobby-HiFi (Made by SEAS) 18MW12T woofer

The loudspeaker has been developed by Bernd Timmermanns.

The crossover consists of:
- a 3rd order high-pass filter (18 dB per octave slope) for the tweeter.
- a 3rd order low-pass filter (18 dB per octave slope) for the woofer.

The frequency response of this speaker is perfectly linear.

The decay spectrum is perfect.

At medium volume, i.e. 90 dB at 1 m, the nonlinear distortions are below 0,3% above 200 Hz.

Our kit consists of

  • Mundorf AMTU80W1.1
  • Hobby-HiFi woofer 18MW12T, produced by SEAS
  • 0,5x PE sealing tape, 5x2 mm, 7.5 m
  • 0,5x Damping Sonofil 100 x 35 cm for 20 litres
  • 0,5x Audaphon Damping 10, 970 x 470 mm, adhesive
  • Binding Post PK31, gold plated (one pair, red and black)
  • 2m Speaker cable 2x2.5 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.

  • Mundorf MCAP EVO Oil 4.7 μF / 450 V
  • Mundorf MCAP EVO Oil 5.6 μF / 450 V
  • Audaphon MKP CAP Superior 1.0 μF / 400 Vdc
  • 2x Audaphon MKP CAP Superior 3.3 μF / 400 Vdc
  • Audaphon MKP CAP Superior 8.2 μF / 400 Vdc
  • Mundorf air core coil L140, 0.82 mH/0.26 Ohm
  • Mundorf air core coil L140, 2.2 mH/0.46 Ohm
  • 0.7 mm air core coil, 0.33 mH/0.48 Ohm
  • 0.7 mm air core coil, 0.39 mH/0.49 Ohm
  • Mundorf ferrite core coil P50 8.2 mH/3.14Ohm
  • Metal-oxide resistor, 10W 5.6 Ohm (green-blue-gold)
  • Metal-oxide resistor, 10W 8.2 Ohm (grey-red-gold)
  • Metal-oxide resistor, 5W 0.33 Ohm 5% (orange-orange-silver)
  • Metal-oxide resistor, 5W 1.0 Ohm (brown-black-gold)
  • Metal-oxide resistor, 5W 2.2 Ohm (red-red-gold)
  • Metal-oxide resistor, 5W 18 Ohm (brown-grey-black)

Kit without cabinet, price per speaker   EUR 937,00 excl. VAT: € 787.39 / $ 858.26

Kit with high-end crossover

The high-end kit is delivered with baked varnish air core coils on important parts of the crossover 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 Mundorf AMTU80W1.1 are of type polypropylen (MKP) Mundorf MCAP EVO Silver Gold Oil 450 V.

  • Mundorf MCAP Supreme 1.00 μF / 600 V
  • Mundorf MCAP EVO Silver Gold Öl 4.7 μF / 450 V
  • Mundorf MCAP EVO Silver Gold Öl 5.6 μF / 450 V
  • 2x Audaphon MKP CAP Superior 3.3 μF / 400 Vdc
  • Audaphon MKP CAP Superior 8.2 μF / 400 Vdc
  • Mundorf baked varnish air core coil BL71, 0.33 mH/0.48 Ohm
  • Mundorf baked varnish air core coil BL71, 0.39 mH/0.51 Ohm
  • Mundorf baked varnish air core coil BL140, 0.82 mH/0.26 Ohm
  • Mundorf baked varnish air core coil BL140, 2.2 mH/0.46 Ohm
  • Mundorf ferrite core coil P50 8.2 mH/3.14Ohm
  • Mresist Classic 5,6 Ohm / 10 Watt
  • Mresist ultra 8,2 Ohm, 3/30Watt
  • Mresist Ultra cooling rod 6,5K/W + Accessories (Set 1)
  • Metal-oxide resistor, 5W 0.33 Ohm 5% (orange-orange-silver)
  • Metal-oxide resistor, 5W 1.0 Ohm (brown-black-gold)
  • Metal-oxide resistor, 5W 2.2 Ohm (red-red-gold)
  • Metal-oxide resistor, 5W 18 Ohm (brown-grey-black)

Kit with high-end-crossover without cabinet, price per speaker   EUR 1102,00 excl. VAT: € 926.05 / $ 1009.39

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).

  • Audaphon MKP CAP Superior 0.68 μF / 400 Vdc
  • Audaphon MKP CAP Superior 18 μF / 400 Vdc
  • 0.7 mm air core coil, 0.27 mH/0.44 Ohm
  • 0.7 mm air core coil, 1.0 mH/0.88 Ohm
  • ceramic resistor 12 Ohm/20 Watt
  • Metal-oxide resistor, 10W 27 Ohm (red-purple-black)

Price per impedance correction for one speaker, to be mounted on a small wooden board.     on request

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 / $ 5.40
We recommend one board per kit (two boards for a speaker pair)


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