Audimax -TL 28.3   Floorstanding as in Hobby Hifi 5/2018

Technical data
  • impedance: 4 Ohm
  • sensivity (2,83V/1m): 85 dB
  • size (HxWxD): 1150 x 318 x 420 mm
  • frequency range (-8dB): 28 - 40000 Hz
  • crossover frequency(s): 200, 1900 Hz
  • speaker type: transmission line

Audimax-TL 28.3 is a three way floorstanding speaker.

Audimax-TL 28.3 is a transmission-line loudspeaker with drivers of SB Acoustics, SEAS and Visaton.

The kit is delivered with the following drivers:
- a SB Acoustics TW29BN tweeter
- a Hobby-HiFi Tieftonlautsprecher 18MW12T (von SEAS produziert) mids driver
- a Visaton TIW 250 XS 8 Ohm 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 band pass consisting of a 2nd order high pass filter (12 dB per octave slope) and a 2nd order low-pass filter (12 dB per octave slope) for the mids-woofer.
- a 2nd order low-pass filter (12 dB per octave slope) for the woofer.

The frequency response of this speaker is perfectly linear.

The decay spectrum as shown in the waterfall diagram is exemplary, free of any disturbing resonance.

At 90 dB and 1 m, nonlinear distortions are below 0,4 % almost everywhere above 100 Hz.

Our kit consists of

  • SB Acoustics beryllium dome tweeter SATORI-TW29BN, neodymium
  • Hobby-HiFi woofer 18MW12T, produced by SEAS
  • Visaton woofer TIW 250 XS, 8 Ohm
  • 2,5x Damping fleece MT Bondum 800 (30 x 50 x 2 cm)
  • 0,5x PE sealing tape, 5x2 mm, 7.5 m
  • 1,5x Damping Sonofil 100 x 35 cm for 20 litres
  • Audaphon Damping 10, 970 x 470 mm, adhesive
  • Binding Post PK31, gold plated (one pair, red and black)
  • 4m Speaker cable 2x2.5 mm2, transparent
  • 1,5x Pan screws 4x20 black, cross recess, 8 pieces
  • Allen wood screws, black, 5x30 mm, 8 pieces
  • Plan for DIY kit

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

  • Mundorf MCAP EVO Oil 3.3 μF / 450 V
  • Mundorf MCAP EVO Oil 8.2 μF / 450 V
  • ClarityCap PWA capacitor 6.8 μF / 160 Vdc
  • ClarityCap PWA capacitor 47 μF / 160 Vdc
  • ClarityCap PWA capacitor 68 μF / 160 Vdc
  • Audaphon MKP CAP Superior 2.2 μF / 400 Vdc
  • Mundorf, electrolytic capacitor, etched, 560 μF/63 Vdc
  • Mundorf, electrolytic capacitor, unetched, 100μF / 50 Vdc
  • Mundorf air core coil L140, 2.2 mH/0.46 Ohm
  • 1.0 mm air core coil, 0.68 mH/0.39 Ohm
  • 0.7 mm air core coil, 0.39 mH/0.49 Ohm
  • 0.7 mm air core coil, 6.8 mH/2.68 Ohm
  • 0.7 mm air core coil, 15 mH/4,45 Ohm
  • Mundorf bs140 core coil 8.2 mH/0.33Ohm
  • Metal-oxide resistor, 10W 3.3 Ohm (orange-orange-gold)
  • Metal-oxide resistor, 10W 8.2 Ohm (grey-red-gold)
  • Metal-oxide resistor, 5W 1.0 Ohm (brown-black-gold)

Kit without cabinet, price per speaker   EUR 1612,00 excl. VAT: € 1354.62 / $ 1476.54

Kit with high-end crossover

The high-end kit is delivered with foil coils and 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 tweeter are of type polypropylen (MKP) Mundorf Mcap Supreme EVO Öl mit 800 V.

Kit with high-end-crossover without cabinet, price per speaker   EUR 1934,00 excl. VAT: € 1625.21 / $ 1771.48

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 22,70 excl. VAT: € 19.08 / $ 20.79

universal PCB

If you prefer to mount the crossover components on a 240 x 165 mm universal PCB instead on wood:
We recommend one board 240 x 165 mm and a half board 159 x 127 mm per kit (two boards 240 x 165 mm and one board 159 x 127 mm for a speaker pair)
Universal PCB RA240, order no.. str-RA240, price per unit:   EUR 8,60 excl. VAT: € 7.23 / $ 7.88
Universal PCB RA160, order no.. str-RA160, price per unit:   EUR 5,90 excl. VAT: € 4.96 / $ 5.40


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