20GDS-4-8 as a low-frequency

It is known that low-frequency drivers are extremely rare on sale. Much more often in stores you can find mid-frequency dynamic heads 20GDS-4-8 (the old name is 15GD-11). If required, they can be used as low frequency ones by increasing the flexibility of the corrugated centering washer. [1]…

For this purpose, two opposite sectors of 90 degrees each are removed from it (see Fig.) The parts to be removed are carefully cut out with a thin sharp scalpel so that no paper flakes and separate threads remain on the cut. Smear the edges of the holes with vibration-absorbing mastic

By this refinement, it is possible to lower the resonant frequency to 60 Hz. All operations are performed through the windows of the diffuser holder for disassembling the head.

The small dimensions of the 20GDS-4-8 head make it possible to use it in small-sized acoustic systems as well. According to a subjective assessment, a two-way acoustic system with a volume of 8 liters, made in the form of a VI, in which, modified by the method described above, a mid-frequency dynamic head 20GDS-4-8 and a high-frequency head 3GDV-1-8 (the old name 2GD-36) are used, quite satisfactorily reproduces both higher and lower sound frequencies.

Obninsk, Kaluga region

Literature

1. Effrucy M., Reducing the resonant frequency of heads. Radio, 1975, no. 3, p. 35