Design Philosophy ELS 5 Electrostatic Loudspeaker

The ELS 5 loudspeaker has been designed as an entry level do-it-yourself electrostatic loudspeaker for those that have limited budget, equipment and time.

As with most ESL’s, the ELS 5 sonic performance, particularly low bass, is room dependant but in most rooms is quite satisfying. In larger rooms integration with a suitable sub-woofer may be necessary for best full range performance.


The ELS 5 loudspeaker consists of a vertically stacked pair of electrostatic panels approximately 950mm tall and 305mm wide making an overall panel size of 1920 x 305.

There is an offset treble strip that runs for approximately 2/3 of each panel from the horizontal centre-line in up and down directions. The treble strip is fed with full range signal but is mechanically unable to reproduce low mid-range and bass frequencies.

Stator design is very simple being a self supporting perforated steel grid with air gap spacers bonded around the perimeter. The air gap spacers are of special design and enclose the edge of the stator thereby preventing stator-to-stator arcing or tracking at the panel edge. The spacers are also as narrow as considered possible, to reduce shunt capacitance. The spacer forming the treble strip is bonded directly onto the stator surface.


Construction is simple.

The air gap spacers are bonded around the perimeter of the stator using a cyanoacrylate adhesive. The spacers are cut to size and mitred at the corners to allow easy assembly.Once the spacers are attached to the stators a copper foil tape EHT rail is applied to one stator and a tensioned diaphragm to the other. Diaphragm tensioning is easy and repeatable using the tools supplied in the kit.After fitting, the diaphragm is made conductive by brushing on our conductive coating. There are no rubbing of graphite or heat-shrinking processes.The two stators are clipped together using a channel section supplied in the kit.The stators are then installed in their enclosures, wired up and connected to the transformer and EHT supplies.

Diaphragm Material

A very thin (3.8 micron) film is used for the diaphragms. Thin films such as this reproduce transients and low level detail with stunning response, leading to the “being there” sensation so often missing from dynamic speakers.

Conductive Coating

The conductive coating we use was developed by us and is proprietary to E R Audio, see the ESL III design philosophy for more detail.

Audio Transformer

The ELS 5 transformers are the same 1:90 ratio units as used in the ESL III kits
The ELS 5 presents a very similar load to the transformer / amplifier as the ESL III, allowing this transformer to be used without compromises.


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