Backes & Müller Sigma

Data

General

• Manufacturer: Backes & Müller
• Model: Sigma
• Type: Loudspeaker
• Years of manufacture: 1984 - 1990
• Made in: Germany
• Color: walnut, ash, ash black, mahogany, oak dark
• Dimensions: 280 x 620 x 290 mm (WxHxD)
• Weight: 20,5 kg
• Original price approx.: 3'700 DM (RRP, pair)

Technical data

• Type: 4-way, closed, fully active
• drivers:
  • Low frequency: 1x 245 mm paper cone, regulated (Backes & Müller).

midrange:

• • • version 1: 1x 120 mm paper cone (Isophon)
    • version 2: 1x 120 mm ceramic cone
  • midrange/high frequency:
    • version 1: 1x 50 mm metal dome (Visaton)
    • version 2: 1x 50 mm ceramic cone

Tweeter:

• • • version 1: 1x 25 mm metal dome (Visaton)
    • version 2: 1x 25 mm metal dome tweeter
• Power output stages: (continuous/dynamic):
  • Version 1: 4x 80 Watt
  • Version 2: 4x 70 Watt
• Frequency response:
• Transition Ranges:
  • Version 1: 300/3000/6000 Hz
  • Version 2: 180/880/4000 Hz

Special Features

• Regulated bass chassis
• Control for level and sensitivity

Remarks

• Other models of the same series:
• Backes & Müller Beta
• Backes & Müller Delta
• Backes & Müller Omega
• Backes & Müller Sigma

Pictures

• Image: Backes & Müller Sigma

Reports

• Report in "FonoForum" 11 / 1984

• Stereoplay issue 12/1986

Sound: very good

• • Manufacturing quality: very good
  • "Rank and Name": Top Class III (Reference)

"The B&M Sigma, for example, sounded quite soft in the bass, but abysmally deep and powerful..."