CT 301   Shelf speaker as in K+T 1/2019

Technical data
  • impedance: 4 Ohm
  • sensivity (2,83V/1m): 83 dB
  • size (HxWxD): 300 x 180 x 160 mm
  • frequency range (-8dB): 60 - 20000 Hz
  • crossover frequency(s): 4000 Hz
  • speaker type: bass reflex

CT 301 is a two way compact speaker.

CT 301 is a bass-reflex cabinet loudspeaker with drivers of SB Acoustics .

The kit is delivered with the following drivers:
- a SB Acoustics SB12PFC25-4 Coax coaxial driver

The loudspeaker has been developed by Dirk Jansen, Julian Jansen and Thomas Schmidt.

The crossover consists of:
- a 3rd order high-pass filter (18 dB per octave slope) for the tweeter.
- a 2nd order low-pass filter (12 dB per octave slope) for the woofer.

The frequency response of this speaker is mostly linear.

The decay spectrum is error-free except for a resonance around 900 Hz.

At low volume, i.e. 85 dB at 1 m, the nonlinear distortions are below 1,3% above 200 Hz and doesn't exceed 2,3% at 95 dB at 1 m between 300 and 15000 Hz.

Our kit consists of

  • SB Acoustics SB12PFC25-4 Coax
  • 0,25x Damping Sonofil 100 x 35 cm for 20 litres
  • Binding Post PK31, gold plated (one pair, red and black)
  • 1m Speaker cable 2x1.5 mm2, transparent
  • 0,5x Pan screws 3.5x17 black, 8 pieces
  • Plan for DIY kit

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

  • Audaphon MKT CAP 3.3 uF / 160 Vdc
  • Audaphon MKT CAP 8.2 uF / 160 Vdc
  • Audaphon MKT CAP 15 uF / 160 Vdc
  • 1.0 mm air core coil, 0.56 mH/0.36 Ohm
  • 0.7 mm air core coil, 0.15 mH/0.28 Ohm

Kit without cabinet, price per speaker   EUR 65,00 excl. VAT: € 54.62 / $ 62.27

Additionally you need for the bass reflex port a installation tube of 25 mm diameter and a length of 140 mm.

Kit with high-end crossover

The high-end kit is delivered with baked varnish air core 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. The capacitors for the SB Acoustics SB12PFC25-4 Coax are of type polypropylen (MKP) Audaphon 400 V.

Kit with high-end-crossover without cabinet, price per speaker   EUR 77,00 excl. VAT: € 64.71 / $ 73.76

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 7,90 excl. VAT: € 6.64 / $ 7.57

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.. I-2765, price per unit:   EUR 3,70 excl. VAT: € 3.11 / $ 3.54
We recommend one board per kit (two boards for a speaker pair)


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