Vintage Microphones

BBC PGS (1953)

Developments of magnetic materials made possible the PGS mic, which was introduced in 1953. This weighed only 2½ lbs. and although the ribbon was only 1 inch long compared to the AXBT's 2½ inches, the output was only 4dB lower.

One problem with ribbons is that the HF response could easily drop off. Placing a perforated fibre baffle on each side of the ribbon within the housing gradually lifts the HF by means of resonance.


The shorter ribbon allowed the mic to be tilted to a greater degree than was permissible with the AXBT, which was limited to 20°. At greater angles than this there was cancellation of the higher frequencies due to the length of the ribbon being similar to the wavelength of the incident sound, although in the days before EQ was available in the studios, tilting the mic could cure a speaker of excessive sibilance. The same could not be done with the PGS.

Why PGS? It stands for Pressure-gradient Single, the 'S' referring to the single magnet.