BBC Marconi AXBT microphone

Marconi AXBT microphone

The BBC Marconi AXB pressure gradient microphone was introduced in 1934, reputedly as a means to avoid the cost of importing RCA44 microphones from the States.


With its 2.5 inch ribbon and bass proximity boost, it became synonymous with the ‘voice of Aunty’ and an iconic symbol of the Corporation’s global reach.

bbc-axbt-chinese-sectionSubsequently improved with advances in magnetic materials, the T-painted AXBT (see top photo) with Ticonal magnet appeared in 1946 with an improved sensitivity for 6dB more output gain and better transient response.


Whilst designed primarily for the speaking voice,  a fabulous microphone for ambient applications such as drum overhead with a tight angle of incidence and general room vibe in the modern music studio.

STC 4038 microphone

4038 employing the old BBC handkerchief trick

Iconic BBC ribbon design, commercially manufactured under licence by Standard Telephone & Cables using spider technology.


Developed from the PGS, the 4038 was the BBC’s successful attempt at designing a general purpose pressure gradient microphone, with excellent linear performance at a reasonable size and cost compared to the AXBT.

The red line is Cole’s master reference microphone, kept in their anaechoic cupboard

Two versions were produced, a 30 Ohm version for outside broadcast and television studios, a 300 Ohm version for the sound studio.

Used just about everywhere in the BBC.

STC standard T-bar for 4038s, with debatable comb filtering effect

Wonderful on just about everything!