8
A perfect point source produces a
spherical wave pattern.
The air particle movement at a plane
some distance from the source.
An identical movement in the ESL
membrane produces and identical
wave front
The membrane carries a constant
charge. The charge on the electrodes
fluctuates according to the music
signal.
The music signal is fed first to the
centre section, then to each ring in turn
via delay coils
Electrodes
Input
Transformer
Polarising
Voltage
High Resistivity
Membrane
Input
1.
2.
3.
4.
5.
1.
2.
3.
4.
5.
Naturally produced sound emanates
from a point. Virtually no loudspeaker
comes close to achieving this – but the
Quad approach comes closest of all.
The ESL is dipolar, producing front
and rear radiation. It has no box so
there is no colouration. Using large
panels ensures well-maintained bass
to well below 40Hz. The centre two
panels in each Quad ESL Loudspeaker
incorporate concentric rings on the
outer grid-plates around the diaphragm.
Each ring is subjected to a minuscule
time delay and attenuated by its own
individual circuit, the sound spreading
gradually from the centre outwards
through each successive ring. This
carefully structured delay line creates
a near-perfect spherical wave front
originating from an apparent point
400mm behind the loudspeaker.
Imaging is pinpoint and there is no
‘sweet spot’ – all listeners receive a full
sonic presentation.
The result is a loudspeaker of
unsurpassed accuracy. The Quad
ESL is probably the lowest distortion
loudspeaker ever made.
electrostatic
The
principle
