STC 4021
Manufacturer:
STCModel:
4021Country of Manufacture:
United KingdomMicrophone Type:
DynamicPolar Pattern:
CardioidProduction Start Year:
1935Production End Year:
1973Rarity:
2
Audio Recordings:
Speech (male) recorded with an STC 4021J 'ball and biscuit' microphone.
Multiple quality options available
Speech (male) recorded with an STC 4021 with VIE grill fitted.
Multiple quality options available
Nylon string guitar recorded with an STC 4021 with VIE grill fitted.
Multiple quality options available
Impulse Response Files:
Impulse Response file of the STC 4031J Ball and Biscuit microphone.on axis
STC_4021_Ball_Biscuit_OnAxis.wav
Impulse Response file of the STC 4031J Ball and Biscuit microphone, perpendicular to sound source
STC_4021_Ball_Biscuit_Vertical.wav
Impulse Response file of the STC 4031 VIE microphone, on axis
STC_4021_VIE-Grill_OnAxis.wav
Impulse Response file of the STC 4031 VIE microphone, perpendicular to sound source
STC_4021_VIE-Grill_Vertical.wav
Frequency Response:
Microphone History:
The STC 4021 was introduced by the Standard Telephone Company in 1935. The most famous version has a flat circular screen in front of the diaphragm, which gives it a very uniform omnidirectional pickup pattern, suitable for recording groups of speakers or musicians. The spherical body and circular screen gave rise to the name 'ball and biscuit' or 'apple and biscuit'.
There were several evolutions of the 4021, denoted with different letters (A, C, E, J etc.). These vary in sensitivity. We have seen models marked with A, C, E and J. According to the Science Museum, the model F was made in 1950.
The 4021 microphones were supplied with different grills and baffles which made them suitable for a wide variety of applications. The VIE model was used with a parabolic dish, to detect approaching aircraft in World War 2.
This microphone is referenced in the title of the song "Ball and Biscuit' by The White Stripes, from their album Elephant. The song was recorded at to Rag Studies in London which had a wide selection of vintage microphones including several STC models.
From Hi-Fi Yearbook 1965-66
4021-J. Spherical omni-directional moving coil. Flat response 30- 15,000 c/s. Impedance 30 ohms. Sensitivity -80 dB. Price : £16 10s.
Technical Description:
MEAN SENSITIVITY for model STC 4021J
Open circuit voltage per dyne/sq.cm. (micro-bar): 0-100 mV
Open circuit voltage level per micro-bar ref. I volt: -80 dB.
Power delivered into 30 ohms for 1 micro-bar, ref. 1 mW: -71 dB.
American ASA rating ref. 1 mW: - 146 db
ELECTRICAL RESISTANCE
Resistance: 20 ohms; Nominal impedance: 30 ohms.
IR files
Impulse response files have been supplied with the microphone positioned horizontally (on axis) and vertically to the source. We tested one example fitted with the usual biscuit screen and another with the VIE grill.
