Electrostatic Loudspeakers (ESL)
It is a widely accepted fact in the audiophile world that the ESL is at the pinnacle of sound reproduction. The simple reason for this is that they produce a very fast transient response due to the light weight of the diaphragm which cannot be equalled by any conventional electromagnetic or conventional cone loudspeaker (CCL). Another common fact is that the ESL provides an exemplary frequency response both in amplitude and phase. The transparency is also superior to CCL because of the large radiating surface.
The differences between an ESL and a CCL are significant. Unlike a CCL, which is comprised of cones or diaphragms of varying size, i.e. – tweeter (for high frequencies), woofers (for mid-range frequencies) and subwoofers (for low frequencies or LF), the ESL is constructed of a single thin diaphragm stretched and fixed between two electrode plates. The electrodes carry a positive charge and the diaphragm carries a negative charge. When a music signal is passed through the ESL it carries a waveform that is replicated by the electrodes which in turn move the diaphragm thus creating sound. In simple terms, it provides one surface to reproduce most of the audible frequency bandwidth (proportionate to size).
Despite ESL’s exceptional sound quality, it has had some issues which have restrained the technology being accepted as a mainstream product. These include:
- Poor reliability
- Insufficient bass
- Poor dispersion
- Low sensitivity
- High load amplifiers
- Large physical size
- High manufacturing costs
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