We have now released the replacement for the elderly but respected ESL III and ESL IIIb speakers. The new speaker is called the ESL IV
        (I know, quite unimaginative!)

Go HERE to see more details and a review by one of the first users.

To go directly to Geoff’s review go HERE. Gary’s ESL IV page and cabinet service can be found HERE.

Frank’s ESL IV review can be seen HERE.

More information and updates are now available on our 505 mini panel page. Click on this  link or on the Mini Panel box to the left to read about it and see what it looks like.

We have updated the 505 page with some more information from a 505 user, click here Greg's Project to see Gregs project.

Follow this LINK to read a recent review for our new 3 transformer version of the Acorn ESL.

While we have endeavored to maintain our low pricing, inevitably there are some increases to be made due to raw material increases and the drop in the Oz dollar. Be sure to refresh this page from your server so you see the revised pricing.

Note, we still have some spare parts for owners of ESL III’s and IIIb’s available and still offer support (as always).

If you own some Quad 57 electrostatic loudspeakers that are in need of repair we have posted a complete repair story from Meinolf, a client in Germany. Click HERE to take you to this page.

Our flagship ESL kit, the Acorn, has undergone some improvements to the structure and electronics, go to our Acorn page or click here to see what we’ve done.

US Distributor:- Mike Beck at Beck Audio beckaudio@gmail.com

We have added a Donation Page to the web site. This has been created because we have had customers that we have helped through tricky repairs want to donate some money as a thank you for the assistance we have provided. 

Go to DONATE to read more.


Exciting new product, the improved 505 panel and dynamic bass system.

Following the unexpected unavailability of the 440 mini panel ESL we decided to create our own improved version. Our customer feedback on the 440 product was very good indeed with the only criticisms being low sensitivity and a narrow dispersion pattern.

Because we started out with a clean canvas we had the freedom to design to our wish list which has led to a very nice loudspeaker. The panel has grown in height a little going from 440mm to 505mm, width has reduced from 168mm to 150mm. The panel thickness has reduced from 8mm to 5mm allowing a very slender frame to be used.

These changes plus changes to the conductive surfaces within the panel have resulted in a panel with excellent frequency response, dispersion and sensitivity

As with the 440 mini panel, the 505 ESL panels are supplied ready to be mounted in a baffle of your choice be it Perspex, glass, timber, lacquered MDF etc. They come complete with a ready built and tested power supply and audio transformer. All you have to do is mount them in a baffle, connect them up and play some music.

 Go to our MINI PANEL page for further details


All of the prices shown on this site are in Australian Dollars only.

We are happy to provide a quote in your currency upon application.

We will provide quotations for freight or postage of components based on the weight of the package. We will normally quote registered airmail or Pack and Track for overseas small packages and will give a courier option if required.

We normally quote the best rate obtainable at the time of shipping for loudspeaker kits. 

While we make every effort possible to minimise customs duty and taxes, customers should make enquiries whether the intended import will accrue any additional duty or tax in their own country


This website is best viewed with your browser set to medium size text, large text will cause overwriting of text and pictures etc. Please feel free to comment if difficulties are experienced navigating this site.



Side group
Side group

While we make every attempt to provide products and service that will suit most customers, occasionally there will be an application that simply does not suit our products.

E R Audio Pty Ltd reserves the right to refuse sale of a product where, in the opinion of E R Audio Pty Ltd, it is not in the best interest of the client to provide it.

Any correspondence that takes place between E R Audio Pty Ltd and an external party is private and confidential.

E-mail messages sent from E R Audio Pty Ltd to any person enquiring about any of the products shown on our website or for any other reason is also private and confidential and as such may not be copied, reproduced or disseminated in any other form without the written permission of E R Audio Pty Ltd. 

Please note, some countries levy duties and taxes for imported audio equipment, these charges are the responsibility of the purchaser, not ER Audio Pty Ltd. Australia has trade agreements with several countries so no import charges apply, but this is not the case for every country.

We cannot be held responsible for any fees that are applied for importing any of our products. If you are in doubt, check with your local government to see if charges will apply.

One of our Italian clients has been kind enough to fully translate our Quad 63 - 2905 repair manual into Italian and has made it available to us to assist Italian repairers keep their speakers running properly. He has also supplied a brief description of the repairs he made and the equipment he used. The English version of this can be found HERE. Italiano HERE.


Final 0.3 and Martin Logan owners may find this of interest
We are in the process of upgrading our very well respected Acorn full range ESL to eliminate the plastic CNC support panel. The speaker will use 4 discrete panels on each side in the near future. This allows us to increase the bass panel area by around 15% without changing the width of the finished speaker.
I won’t go into this too deeply here but the new Mid-range / treble panel has been used very successfully in a pair of Final 0.3 speakers that had suffered panel fade.

The new panel is 920 x 200mm and will fit in the Final frame easily, it will also fit some Martin Logan models. No changes are required to the drive electronics.

Click HERE to see the panel fitted to Final 0.3 speakers.


If you have any queries at all for any of our products contact us on rob@eraudio.com.au

One of our local clients, Gary, purchased a pre-assembled ESL IV kit a few months ago and has now finished the project. The enclosures built by a local master craftsman are constructed in Cherry timber and finished in a satin clear lacquer. The sonic performance and appearance is stunning! In fact, so good Gary has decided to offer a construction / installation service for those not equipped to make their own cabinets and install the panels.

See Gary’s page HERE, which gives the full story and more detail of the service he can offer.

Click HERE to go directly to the ESL IV page

Frank in the USA recently purchased a partially built ESL IV kit, the panels were assembled by us, he chose to assemble the electronics.
Frank is very experienced with loudspeaker design and construction and along with a couple of audiophile friends decided to compare the ESL IV with the Quad 63 and Quad 57 ESL’s.

Click HERE to see his story and a couple of comments from yours truly.


More comments on Frank’s review, click on the link below.

Franks review has created a bit of a discussion point, with his permission, I decided to publish the email I received from Geoff querying the validity of a mono comparison. I have included my response to Geoff.

If you wish to add comments to this discussion please do. Send your comments to rob@eraudio.com.au and we will publish them in this blog (assuming they are publishable!!)

Click HERE to go directly to the review page, the latest comments will be at the bottom so you will have to scroll down to read them.

Geoff has very kindly sent in an update to his original post regarding the ESL IV.

 Click HERE to read Geoff’s latest comments.


Very important note for email contact

Please note, our ISP has changed their operation which may affect our reception of email enquiries. All enquiries should be sent to         rob@eraudio.com.au



All other email addresses on this website should be ignored. If difficulty is experienced contacting us please call on +61 8 9397 6212.

We have added a new 505 hybrid project from Stevan in Croatia,
Capture to read about his project and view the photographs.

Those of you that own or are interested in the Acorn MkII loudspeaker should read a review received recently from Gary Jacobson. Capture To read what he has to say about his Acorns.

Attention lovers and users of the classic Quad 57 electrostatic loudspeakers.

As you are all aware, this excellent loudspeaker is one of the most realistic performing speakers ever produced but it does have some shortcomings. Quite often treble panels become damaged by over-driving and, while available in some parts of the world, replacements can be difficult to source.
As such, we have been working on replacement treble panels for this loudspeaker as well as some enhanced replacement items such as EHT supplies and a treble protection board.

 Capture To see what we now have to offer

 We are often asked about the sonic differences is between the ESL IV and the Acorn MkII, Capture to see a detailed response.

Sadly the cost of materials and transport has risen to the point where we are forced to pass some increases on to our customers. We do try to keep some stability in our pricing but cannot do so any longer.


Dragan from Serbia decided to convert a pair of Quad 989’s to the equivalent of Quad 63’s by removing the 2 additional bass panels, cutting down their frame accordingly and changing the cosmetics with new grille cloth etc.

His story can be found by clicking on the link. Capture


We are frequently asked to reduce the declared cost of repair kits and components when sending items to some countries in Europe. While we try to minimise costs to our clients we cannot make false customs declarations so please do not ask. If you are concerned about the cost of importation check with your local government to determine likely costs before ordering. High importation costs when you receive the goods is something you should take up with your government, complaining to us about high importation costs after the event does not help either you or us.

We have now received our very slow to be delivered shipment of audio transformers so can now supply all of our DIY products again.


We are forced into reviewing the prices of some of our products due to the recent materials and transportation increases. We have tried to maintain our prices at a reasonably static level for many years but are now forced to make some small increases.


Quad 63 owners may be interested in the rebuilding information received from Olle, in Sweden. Capture to read about his journey.

David from Victoria has added some tips for DIY’ers to his review, Capture to see what he says.


New ESL IV review. David in Victoria has contacted us with details of his full DIY ESL IV build, Capture to read part one of his journey. This may be of interest to those that are worried about their ability to tackle a full DIY kit.


Over the past couple of years we have been working on improvements to our Acorn electrostatic loudspeaker, having a number of examples in the public domain we are now ready to release it.

To read more about the changes and impact on pricing structure



We have two new reviews of our ESL IV full range electrostatic loudspeaker. Capture to read about Steve’s new speakers.

The excellent cabinet work was carried out by Gary in Queensland.

Bruce also had Gary make his cabinets Capture to read a full review.


   Important Note - We are experiencing some issues receiving email enquiries from some international service providers. If you do not receive a response within 48 hours from our regular addresses published on this website, contact us directly by telephone on ++61 8 9397 6212. Remember we are ahead of US eastern states by around 12 hours.


When ordering our DIY ESL kits we ask for a deposit of 10% to confirm the order. Sometimes a change of circumstance occurs for our client and the order is cancelled, as has happened recently. This occasionally causes us problems because the stock we have has been allocated to that customer. If stock is low and another enquiry is received for the same product but cannot go ahead because of the low stock level, not only do we lose the original sale but the potential sale to the second client.

Please be aware we will now charge an order cancellation fee of 25% of the deposit to cover this.

Please stay healthy and thanks for your support. 

New comments on the ESL IV review, see below.

Attention Quad 63 to 2905 owners.

If you own a pair of these classics and they have become troublesome over the years and you have been considering repairing them but are worried about the outcome, Alexis story may be of interest to you. Capture

There are probably hundreds of pairs of Quad electrostatic speakers that are not working, tucked away in garages, sheds, attics etc because the owner doesn’t want to get rid of them. Quad speakers command a very low price when not working so the financial loss is hard to bear or the owner likes the performance but commercial repairs are very expensive. We may have the solution for you. See HERE.

Lars in Sweden has sent some details of his 505 projects. One is a TV speaker project the other is a full range audio system using a stacked pair of 505 panels. Capture to read and see what he did.


Matt in Perth has sent us details of his new 505 project,
 Capture to read about it.

December 2023 Update.
Important Note

Due to costs of raw materials increasing uncontrollably, we have temporarily suspended production of our Acorn MkII and ESL IV kits.

We are currently exploring alternative production methods in an attempt to contain rising costs. If you are contemplating building either of these projects please contact us and we will put you on our list for contact once we know what will be available and when.

Any changes to construction will in no way compromise the sound quality of these speakers.

The 505 panels are in stock and will still be available

See below for links to new customer projects

Quad 63 - 2912 owners may be interested in this. Dave from Australia has sent us some information about rebuilding his Quad 63 speakers. Click here to read what he says.

We have also received some pictures of Geoff’s new enclosures for his ESL IV speakers. Click here to see them. To start Geoff’s ESL IV journey click HERE.

Fine Audiophile Equipment

Designers and Manufacturers of Electrostatic Loudspeakers and Fine Audiophile Equipment

E R Audio Pty Ltd. ACN: 120 797 775, ABN 48 120 797 775


© Copyright E R Audio 2002-2018 Legal Website designed by RNM

E R Audio Home
Electrostatic Loudspeakers  
by E R Audio