Lester Smith on the EMI HB1E Microphone

The HB1E Microphone

Abbey Road’s microphone curator Lester Smith tells us about the iconic EMI HB1E Microphone.

The HB1E was the brainchild of Alan Blumlein who joined EMI in 1931. He designed and patented this microphone in May 1931 and called it the HB1A, putting his Chief Engineer Herbert Holman’s initial (H) before his own.

There were several improvements upon this until the HB1E became the standard microphone on all recordings made at EMI’s new studio in Abbey Road, St John’s Wood until the introduction of 'Capacitor' microphones in the '50s, also known as 'Condenser' microphones.
 
 
The HB1E is an electro-mechanical device, with the main elements being a coil of fine wire attached to a thin membrane, the diaphragm, situated inside the field of a very powerful magnet. Sound pressure upon this diaphragm would produce very small alternating voltages (less than 1/1000th of a volt) which corresponded exactly to the sound of the singer or instruments.

Amplifiers are required to make these sounds loud enough for recording purposes and at the time they were one of the finest ‘moving coil’ microphones manufactured by EMI, and supplied to the BBC for their new radio broadcasting stations.

Today, they are generally known as ‘Dynamic’ microphones and are used all over the world for broadcasting, concerts and events. The HB1E that was in use at Abbey Road Studios is now stowed away at the EMI Archives in Hayes due to its significant importance and rarity.