Libra (1977)
Helios Electronics
Libra
Modular highly-configurable analogue theatre sound desk
Developed by John A Leonard and Alastair Goolden. Commercial version was created in collaboration with Helios Electronics around 1977.
Winner of ABTT Product Of The Year Award in 1978.
John Leonard writes (October 2025):
OK, I will give you chapter and verse on the development of the Libra Desk, whose original design idea came from Alastair Goolden, with development by me and him in a series of brainstorming sessions and the involvement of Neil Adams and Brian Croney at Helios Electronics - yes, that Helios, if you're a fan of custom built studio mixing desks.
It's a long story and I don't have time right now, but here's a very old photo of the original desk, hand built by me and Alastair over a long hot summer back in the mid 1970s. Oh and that includes the front panel, which was hand-drawn by me, with the legends done in black Letraset on white paper, then photo-reversed and etched onto anodized aluminium: indestructible, never wore out.
The desk was unfortunately too expensive for most theatres, and the parent company, Helios Electronics had cashflow problems.
However, the desk was hugely powerful. Fully modular, and any input channel strip could be allocated via a rotary knob to receive any input signal, and each channel strip could then be routed to any of the outputs. Sending an input from a single speaker to a series of speakers, while changing the EQ and adding an effect, was as simple as fading in the suitably configured channel strip and fading the previous one out.
Documents
Libra Sound Desk original model (July 1976)
Click on thumbnail to enlarge
[194kb JPEG]
From John Leonard Collection
Libra ABTT Award Winner (May 1978)
Click on thumbnail to enlarge
[382kb JPEG]
From Mike Hall Collection
Catalogue & Journal Entries for Libra in the Backstage Heritage Collection
Back to Sound - Mixing (Helios Electronics)
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