Asterion   Shelf speaker as in K+T 3/2022

Technical data
  • impedance: 6 Ohm
  • sensivity (2,83V/1m): 86 dB
  • size (HxWxD): 490 x 263 x 379 mm
  • frequency range (-8dB): 48 - 26000 Hz
  • crossover frequency(s): 290, 2600 Hz
  • speaker type: bass reflex

Asterion is a three way compact speaker.

Asterion is a bass-reflex cabinet loudspeaker with drivers of SEAS .

The kit is delivered with the following drivers:
- a SEAS MR18REX/XF (H1699-08-06) coaxial driver
- a SEAS CA22RNY (H1471-08) woofer

The loudspeaker has been developed by Dennis Frank and Daniel Gattig.

The crossover consists of:
- a 2nd order high-pass filter (12 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 3rd order low-pass filter (18 dB per octave slope) for the mids-woofer.
- 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 as shown in the waterfall diagram is exemplary, free of any disturbing resonance.

At low volume, i.e. 85 dB at 1 m, the nonlinear distortions are below 0,4% above 300 Hz and doesn't exceed 1% at 95 dB at 1 m between 300 and 15000 Hz.

An excerpt from the Klang+Ton review (Translation of the author into English)

"But even without subwoofer support, the Asterion really nails the bass. The CA22RNY is an old-style-woofer just the way I like it: With a little cabinet volume, it can produce a highly dynamic and at the same time light-footed bass, which is always a bit reminiscent of the classics of the 70s, when you couldn't get deep tones out of stiff and heavy cones, but out of large cabinets. One can forgive the box the missing sub-octave, because it otherwise sounds so incredibly rich and deep. The coax does a very good job in the midrange and high-frequency range - tonally, everything is just on-point, adjusting the personal sound preference is easily possible by directing the tweeter directly to the listening position or a bit off-axis. And then of course there is the spatial illusion - a home game for the Seas-Coax, which sets standards both in the dimensions of the stage image and in the precision in the positioning of voices and instruments. And so you can enjoy everything from rock to classic with the Asterion - a perfect all-round-speaker."

Conclusion of the magazine Klang+Ton:

"The Asterion is a box for all music genres - compact, dynamic and with an impressive spatial image."

Our kit consists of

  • Seas CA22RNY (H1471-08)
  • SEAS MR18REX/XF (H1699-08/06)
  • Bass reflex tube HP70 XL, 70x220 mm, black
  • 3x Damping fleece MT Bondum 800 (30 x 50 x 2 cm)
  • 0,5x PE sealing tape, 5x2 mm, 7.5 m
  • 0,5x Damping Sonofil 100 x 35 cm for 20 litres
  • Binding Post PK28 I, gold plated (one pair, red and black)
  • 3m Speaker cable 2x1.5 mm2 black/red
  • 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.

  • Audaphon MKP CAP Superior 2.7 μF / 400 Vdc
  • Audaphon MKP CAP Superior 3.3 μF / 400 Vdc
  • Audaphon MKP CAP Superior 12 μF / 400 Vdc
  • 2x Audaphon MKT CAP 33 μF / 160 Vdc
  • 2x JB, electrolytic capacitor, bipolar, 100 μF/50 Vdc
  • JB, electrolytic capacitor, bipolar advanced, 22μF / 50 Vdc
  • Mundorf baked varnish air core coil BL71, 0.05 mH/0.18 Ohm
  • Mundorf baked varnish air core coil BL100, 0.56 mH/0.36 Ohm
  • Mundorf baked varnish air core coil BL100, 0.82 mH/0.45 Ohm
  • 0.7 mm air core coil, 0.56 mH/0.55 Ohm
  • Mundorf H core coil H71, 6.8 mH/0.7 0hm
  • Mundorf H core coil H71, 22 mH/1.49 0hm
  • Mundorf H core baked varnish coil BH100, 2.2 mH/0.21 0hm
  • Mundorf H core baked varnish coil BH125, 6.8 mH/0.37 0hm
  • ceramic resistor 3.9 Ohm/20 Watt
  • ceramic resistor 4.7 Ohm/20 Watt
  • ceramic resistor 8.2 Ohm/20 Watt
  • Metal-oxide resistor, 10W 6.8 Ohm (blue-grey-gold)

Kit without cabinet, price per speaker   EUR 639,00 excl. VAT: € 536.97 / $ 569.19

Price for a pair of custom speakers of any color   EUR 2580,00 excl. VAT: € 2168.07 / $ 2298.15

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 SEAS MR18REX/XF (H1699-08-06) are of type polypropylen (MKP) Mundorf Mcap Supreme EVO Öl 800 V.

  • Mundorf MCAP EVO 12 μF / 450 V
  • Mundorf MCAP EVO Oil 3.3 μF / 450 V
  • Mundorf Mcap Supreme EVO Oil 2,7 μF / 800V
  • 2x Mundorf MKP capacitor 33 μF / 250 V
  • Mundorf, electrolytic capacitor, etched, 56 μF/100 Vdc
  • Mundorf, electrolytic capacitor, etched, 68 μF/100 Vdc
  • Mundorf, electrolytic capacitor, etched, 100 μF/100 Vdc
  • Mundorf baked varnish air core coil BL71, 0.05 mH/0.18 Ohm
  • Mundorf baked varnish air core coil BL71, 0.56 mH/0.64 Ohm
  • Mundorf baked varnish air core coil BL100, 0.56 mH/0.36 Ohm
  • Mundorf baked varnish air core coil BL100, 0.82 mH/0.45 Ohm
  • Mundorf H core baked varnish coil BH71, 6.8 mH/0.7 0hm
  • Mundorf H core baked varnish coil BH71, 22 mH/1.49 0hm
  • Mundorf H core baked varnish coil BH100, 2.2 mH/0.21 0hm
  • Mundorf H core baked varnish coil BH125, 8.2 mH/0.42 0hm
  • ceramic resistor 8.2 Ohm/20 Watt
  • MResist Supreme 3.9 Ohm / 20 Watt
  • MResist Supreme 4.7 Ohm / 20 Watt
  • Mresist Classic 6,8 Ohm / 10 Watt

Kit with high-end-crossover without cabinet, price per speaker   EUR 773,00 excl. VAT: € 649.58 / $ 688.55

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 MKT CAP 4.7 μF / 160 Vdc
  • 0.7 mm air core coil, 0.39 mH/0.49 Ohm
  • ceramic resistor 10 Ohm/20 Watt

Price per impedance correction for one speaker, to be mounted on a small wooden board.     EUR 8,00 excl. VAT: € 6.72 / $ 7.13

universal PCB

If you prefer to mount the crossover components on a universal PCB instead on wood
PCB 220x155 mm, order no. I-8805002, price per unit:   EUR 11,80 excl. VAT: € 9.92 / $ 10.51
We recommend one board per kit (2 boards per speaker pair)


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