We’ve been making some changes at Agent Audio HQ recently, amongst them, updating our Microphone Collection.
The most recent additions to the collection are the Northern Electric 633A “Salt Shaker”, often badged under Altec or Western Electric, and the STC 4021c “Ball and Biscuit” or “Apple and Biscuit” Omni-direction pressure gradient.
I’ve been after one of these for a while. The famous STC 4021c “Ball and Biscuit” or “Apple and Biscuit” (depending on which BBC engineer you ask). The STC 4021c is an Omni-direction pressure gradient microphone which resembles a small cannonball. It sounds best as a drum mic with a genrous amount of FET based compression.
The Altec 633A, “Salt Shaker” microphne was sold under different brands, such as Western Electric. This one is branded Northern Electric. A quick look inside to rewire it for XLR operation revealed that this particular design is from 1941. It’s interesting to note the tube which equalises the pressure at the rear of the capsule making it uni-directional.