Scan-Dyna A-25

Data

General

• Manufacturer: Scan-Dyna
• Model: A-25
• Type: Loudspeaker
• Years of manufacture: 1968 - 1974
• Made in: Denmark
• Colour: Walnut
• Dimensions: 290 x 500 x 250 mm (WxHxD)
• Weight: 9 kg
• Original price approx.: 345 DM

Technical data:

• Construction: 2-way aperiodic (half-open, "Acoustic Resistor" / "Resistive Port/Vent" like Dynaudio Variovent)
• drivers:
  • woofer: 250 mm cone, SEAS H-336 (according to surround) / type 25TV-EM (according to label), 4 Ohm.
  • midrange driver:
  • tweeter: 40 mm dome, SEAS H-087, 6 Ohm (measured: 4.8 Ohm).

Power handling (nominal/music): 35 W / 90 W efficiency: 88 dB / W / m

• Frequency response: 32 - 20'000 Hz
• Crossover: 1'500 Hz
• Impedance: 4 Ohm

Special Features

• Aperiodic damping system
• Removable front
• Height adjustment of 5 positions for listening room adaptation with the following features:
  • 1) Low boost
  • 2) Linear frequency response
  • 3) Weak damping - Described as normal (probably means typical listening room)
  • 4) Slightly stronger damping for "hard" rooms

5) Strong damping

Remarks

• Other models in the same series:
• Receiver:
• Scan-Dyna 2000
• Scan-Dyna 2400
• Scan-Dyna 3000
• Scan-Dyna 4000

• Record Player
• Scan-Dyna 1400
• Scan-Dyna 1700

• Speakers:
• Scan-Dyna A-10
• Scan-Dyna A-20
• Scan-Dyna A-25
• Scan-Dyna A-25 II
• Scan-Dyna A-30
• Scan-Dyna A-30 II

• [[Headphones:
• Scan-Dyna K-72x

Pictures

• Picture: Scan-Dyna 3000, A-25

• Excerpt from brochure: Scan-Dyna A-10, A-20, A-25, A-30

• Picture / Scheme: Scan-Dyna A-25

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• 

Reports

Aperiodic: Manufacturer's Comment (from article by J. Gordon Holt, Dec. 1, 1969; about the first A25 version) The aperiodic design is not a bass-reflex approach, since there is no acoustic output through the port. The characteristics of the "plug" in the port are quite critical, necessitating individual adjustment of each system. This added acoustical impedance damps the woofer, improving its response to transient signals. Examination of the woofer cone motion shows that, with this aperiodic design (on which patents are pending), the cone follows the input signal all the way down to DC with far greater precision than is the case with either bass-reflex or acoustic-suspension designs. Dynaco

• Dynaudio called this design Dynaudio Variovent and at Scan-Speak it was "Flow Resistance Vent".

Links

• https://diyaudioprojects.com/Technical/Aperiodic/

• https://www.stereophile.com/content/dynaco-25-loudspeaker