What wood are woofers made of?

The BR 50 is a 3-way Ba reflex-Box, which was manufactured in the energy combine Frankfurt / Oder. It was developed from the experience gained with the BR 25 by VEB Musikelektronik Geithain. Compared to the BR 25, however, some technical changes have been made, which allow a higher sensitivity and resilience with improved sound.

The first to be mentioned is the housing, which is much more complex and of high quality compared to the BR 25. It is made of chipboard and covered with real wood veneer. On the front panel there are milled beads for the 4 loudspeakers and the reflex tube. Furthermore, to mechanically isolate the mid-range speaker from the air volume of the woofer, a small chipboard housing is also glued into the box, onto which the crossover is screwed at the same time.

The mounting of the individual loudspeakers in the box is unusual. They are mounted on the front of the baffle without the screws being visible. Black molded plastic parts are used for this, which surround the loudspeakers, but leave their membranes exposed, and which are screwed into the box from behind (with a total of 30! Screws). For this reason, the BR 50 has a removable rear panel that is held in place by 8 screws and thus enables access to the box from the rear.

In order to achieve a nominal load capacity of 50 watts, two woofers had to be used in the BR 50, which were connected electrically and acoustically in parallel. The 8-ohm version L 7114 of the L 7102 known from the BR 25 with the same acoustic parameters is used as the woofer. It has a very soft foam surround that enables large cone deflections and high rise times for undistorted playback, e.g. of bangs. The membrane, which is light but still stiff due to the embossing, also contributes to this. The voice coil is wound on an aluminum support for good heat dissipation, whereby a high load capacity of 25 VA can be guaranteed. The generously dimensioned drive allows a pulse load of 50 watts.

In conjunction with the bass reflex system, which is tailored to the technical parameters of the two woofers and the speaker volume, a lower limit frequency of 45 Hz is achieved. As a result, the BR 50 has a lower lower limit frequency than other, similarly large loudspeakers in the GDR speaker range, a higher sensitivity and realizes less distortion and better impulse transmission behavior.

In the mid-range branch, the L 7113 with 4 ohms, which has a slightly different acoustics than the basic type L 7102, is used. It has a slightly shorter winding, which gives it a higher sensitivity in the middle frequencies, which is for

use as a mid-range speaker is useful. It works in a small, separate volume in order to be acoustically decoupled from the woofers.

In the tweeter branch of the BR 50, the 25 mm dome tweeter of the type L 7101 known from the BR 25 is used, which has a soaked fabric membrane. It also has a high load capacity of 25 watts. This was specially designed for use in the BR 25, as it not only has to emit high frequencies, but also a large part of the important mid-tone range down to 2600 Hz. Compared to the L 9801 dome with a polycarbonate membrane that is otherwise used, it sounds a little softer, but at only 87 dB it has a relatively low sensitivity. In addition, a horn attachment was provided to improve the radiation behavior, in the case of the BR 50 with a plastic cover.

The three loudspeakers are interconnected via an electrical crossover with a slope of 12 dB / octave for the bass and mid-range, or 18 dB / octave for the tweeter. The crossover frequencies are 800 and 2600 Hz. In the low-frequency and mid-tone branches, coils with a ferrite core are used, in the high-tone branch only MKT capacitors are used. All components of the crossover are housed on a circuit board. The tweeter also has overload protection in the form of a PTC thermistor (21 watt light bulb).

The visual design of the BR 50 is very idiosyncratic and can be traced back to acoustic rather than optical aspects. Designed as a large shelf box, the housing is not very deep, but has a fairly large baffle. The front has a very three-dimensional effect thanks to the molded plastic parts and the slightly offset front panel. The box was labeled with gray and green screen printing on the plastic parts. The membranes of the box are not covered by grids or the like. Protected, there is no additional front panel.
The aluminum-etched type plate on the box and the real ash-wood veneer look very high-quality. Almost all of the BR 50s produced are colored black, only a few boxes are made of light ash.

Since the BR 50 was also produced during the turning point, there are also different turning variants or export versions of this box. One variant has a removable, full-surface, black fabric panel that is attached to the box with 4 (rather western-looking) plastic pins.
Other variants have, for example, cable connection terminals instead of the cable, or a different label (e.g. "enko" for Enenergykombinat).

The BR 50 was presented to the public for the first time at the Leipzig spring fair in 1987.