CT 303   Floorstanding as in K+T 3/2019

Technical data
  • impedance: 4 Ohm
  • sensivity (2,83V/1m): 85 dB
  • size (HxWxD): 940 x 160 x 244 mm
  • frequency range (-8dB): 58 - 19000 Hz
  • crossover frequency(s): Hz
  • speaker type: bass reflex

CT 303 is a two way floorstanding speaker.

CT 303 is a bass-reflex cabinet loudspeaker with drivers of Omnes Audio .

The kit is delivered with the following drivers:
- a Omnes Audio BB3 AL full range driver
- a Omnes Audio BB3 AL full range driver

The loudspeaker has been developed by Thomas Schmidt and Bernd Burghardt.

The crossover consists of:
- a blocking circuit in series with the full range driver.
- a first order low-pass filter (6 dB per octave slope) for the full range driver.

The frequency response of this speaker is nearly linear.

The decay spectrum (waterfall spectrum) shows a decelerated swing-out behaviour in the mid-range.

At low volume, i.e. 85 dB at 1 m, the nonlinear distortions are below 0,7% above 300 Hz and doesn't exceed 1% at 95 dB at 1 m between 300 and 15000 Hz.

Our kit consists of

  • 2x Omnes Audio, full range BB3 AL
  • 0,5x PE sealing tape, 5x2 mm, 7.5 m
  • Damping Sonofil 100 x 35 cm for 20 litres
  • Terminal T105 Au, with brass, gold plated
  • 2m Speaker cable 2x1.5 mm2, transparent
  • Pan screws 3.5x17 black, 8 pieces
  • Plan for DIY kit

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

  • Audaphon MKP CAP Superior 15 μF / 400 Vdc
  • 1.0 mm air core coil, 0.33 mH/0.26 Ohm
  • Mundorf H core coil H100, 3.9 mH/0.3 0hm
  • Metal-oxide resistor, 10W 5.6 Ohm (green-blue-gold)

Kit without cabinet, price per speaker   EUR 136,00 excl. VAT: € 114.29 / $ 123.43

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 Omnes Audio BB3 AL are of type polypropylen (MKP) Clarity-Cap ESA 250.

Kit with high-end-crossover without cabinet, price per speaker   EUR 154,00 excl. VAT: € 129.41 / $ 139.76

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 10,50 excl. VAT: € 8.82 / $ 9.53

universal PCB

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 / $ 3.81
We recommend one board per kit (two boards for a speaker pair)


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