Nubert Type 471 A

Data

General

• Manufacturer: Günther Nubert electronic GmbH Schwäbisch Gmünd
• Model: Type 471 A
• Years of manufacture: 1980/81
• Manufactured in: Germany
• Colour: Walnut (veneer + corner sticks)
• Dimensions: 585 x 315 x 275mm (HxWxD)
• Weight: 14 kg
• Original price approx.: 405.- DM

Technical data

• Type: Bass reflex
• Chassis:
  • TT 205mm

HT 106x82mm (25 mm dome tweeter)

• Power handling: 100 Watt
• Efficiency: 86 dB / 1 W / 1m
• Frequency response: 42 - 18,000Hz +- 3 dB (at a dispersion angle of 30°)
• Crossover: approx. 2 kHz
• Impedance: 4 Ohm

Special Features

• Switch for treble adjustment

Remarks

Further (historical) models of the same series: Nubert Type 388 (85 W / 45 x 25 x 23 cm), Nubert Type 554 (180 W /65 x 36 x 32 cm)

Concerning: Aging of foam surrounds (Text Nubert electronic 2004)

Since about 1972, the outer diaphragm surrounds of bass and midrange loudspeakers (so-called "surrounds") have increasingly been made of foam instead of folded paper, fabric or rubber, because this material has very favourable acoustic properties due to its internal damping. 5 years of long-term testing in discotheques did not reveal any problems, - almost unlimited durability in everyday use thus seemed logical. In the meantime, however, it has become clear that all foam surrounds from the 70s to the mid 80s become unusable after about 13 to 20 years (mainly depending on temperature and UV radiation). Mostly they disintegrate because their mechanical strength (similar to wet newsprint) becomes less and less. All speaker manufacturers are affected by this problem. In most cases, a bass speaker will work perfectly acoustically until it suddenly fails; - sometimes even (at lower volumes) better than a new driver, because the softening clamping lowers the resonant frequency, allowing deeper bass to be emitted. Replacing the surrounds on defective loudspeaker systems would in principle be possible if the loudspeaker has not yet emitted any strong scratching noises. However, replacing the beading is time-consuming and not crowned with absolute certainty with success. As a rule of thumb it can be assumed that this kind of replacement is only profitable for "exotic" woofers that cost more than about € 100 and for which there is no longer a supply of spare parts. Since a few years there are also repair shops that specialize in replacing the surrounds (with diaphragm). However, it can be assumed that the differences in sound are rather greater than with the replacement types recommended by us. Since we have recognised the ageing of foam surrounds as a problem, we only use loudspeaker drivers with special rubber surrounds, but these require more complex crossovers in order to achieve equally good acoustic properties in the transition area to the tweeter. For repairs of our earlier speaker models with foam surrounds we use the special silicon coated successor types that have only been available since the beginning of the 90's and are supposed to last "forever" according to the manufacturer. After lengthy series of tests regarding "artificial aging" (in climatic chambers and with different infrared and UV radiation), we assume a service life that is at least 50% longer (20-30 years). For some speaker models we can also offer a replacement by speakers with rubber surrounds, which (even without changing the crossover) are hardly distinguishable in terms of sound.