Friday, December 21, 2007

DIY Electrostatic Loudspeakers / ESLs - Stators and Supports

In the initial step of the build, you are required to glue the white and black spacers to the support structures, but this was already done for me by ER Audio. This probably saved me a day or 2. Next the steel grids that formed the stators had to glued to the support structure.Here I have the Support Structures and Stators laid out in a dry run to make sure everything fits.... and it does, perfectly. It also helps me figure out where everything goes. The picture shows the narrower treble panels. The large white bottle that you see is the polyurethane glue that will be used to attach the stators to the support structures. The glue takes 24 hours to cure and is very very strong. Good stuff. Also shown in the picture are wooden strips that will be used as pressure pads. These pressure pars will be used to push the stators and the support structures together to ensure a good bond during the curing process. I also lay out the stators for the full range panels. Notice that the screws that will transfer the +ve/-ve charge to the stators are 'brazen' in place. Again, a very elegant and simple design.There are 2 treble and 4 bass panels, in total 12 stators and 12 support structures to glue. This could get tedious. So I setup a 'production line' where the polyurethane glue is rolled onto 4 stators at one time. The polyurethane glue is rolled onto on the entire stator, this serves 2 main purposes; 1. to glue the stators to the support structure; and 2. to dampen the stator from vibrations and ringing as it is only 0.6mm thick. The Polyurethane layer applied is very thin usnig a mini paint roller. The polyurethane is applied over the entire surface on one side of the stator only. The stator side that will eventually face the diaphragm is left clean. If you are thinking that the polyurethane serves as an insulator, I cannot be sure of how well it will serve as a insulator, especially with so much voltage running through it. Best is still to avoid coming into contact with the speakers when it is in operation.
The Support structures are laid out on the table, ready to accept the stators once the glue is applied. There are in total 8 full range panels and 4 treble panels to be glued. So I do it in 3 runs of 4 each, thats 3 days of gluing, curing and waiting.... ho hum. After rolling on the polyurethane glue, I place the stators on the support structure. And the I use the pressure pad and weights to ensure a good bong all along the surface of the panelI found a way to weigh down 2 panels at a go... The next picture shows the first batch of 4 panels fully cured after more than 24 hours of bonding under pressure. While applying the polyurethane, the roller brush left many tiny bubbles, shich you can see in the picture. For the 2nd and 3rd runs, I worked out a simple brushing technique that got rid of the bubbles very effectively. You learn real quick when doing this.After gluing all the stators to their support structures, I place them all againt the wall for a dry run fitting using the channel clamps.This is how a completed side of the ESL would look like... a treble panel sandwiched by a full rnage panel on either side.A closer look at one of the full range panels fitted with the channel clamp. Remember that a panel is made up of 2 support/stators, I attached the channel clamps to the front and rear support/stators that make up one panel. As expected the clamp is very tight and also serves as a well insulated frame so that the completed panel can be handled safely. The only concern here is that because the clamps are so tight, I may damage the diapharms when I finally assemble the completed panels. Guess I need to practice this somemore before I do it for real.

ext I install the clips and copper strips. The clips will be used to connect the wires to the EHT aupply that will eventually bring electric charge to the diaphragm. Here is the clip installed on the support structure. I attach the clip first so that I know where the copper foil needs to exit the air gap spacer on the other side. The copper foil will come into direct contact with diaphragm, thus delivering the EHT charge. Before I attach the copper foil, I lightly sand the air gap spacers so that the surface is smooth and free of any adhesives that may be left over from the production process or from the previous tasks. Once done I clean the air gap spacers with some thinner. Only after I am sure the surface is clean and smooth do I attach the copper foil to the air gap spacers.This is a relatively simple task but one must be very careful with the foil as it is very thin and can snap as you fold in 90 degrees at the corners.So that's it, the stators/support assembly is completed.

The next step is the Installation of The Diaphragms

Thursday, December 20, 2007

DIY Electrostatic Loudspeakers / ESLs - Out of the Box

I received the LARGE box containing the ESL III components from ER Audio a couple of weeks before christmas of 2006. Happiness is when a huge package is delivered undamaged by the courier. The size of the box was a real surprise. Mentally. I was not prepared for such a large box.
I immediately opened up the both to examine the contents. Upon opening the box, I just stared at the contents for what seemd like hours..... there were just so many components. Panic started to set it... what parts are these..., what am I getting myself into..., where do I even begin...
I thought first things first, I'd do a brief inspection and an inventory check against the components list. Well everything seemed complete and in order. All components accounted for. nothing was damaged... perfect packing. During the inspection the items that caught my eyes (and hands) were the audio transformers. They are really humongous lumps of black iron making them the heaviest items in the package. If I ever need a door stop in gale force winds, this would be it!! Here they are in all their ferrous glory:
Further rummaging in the package revealed the CNC'ed support structures tucked at the bottom of the package. These support structures are made from plastic and milled on a CNC machine to generate the desired structure. These support structures will hold the stators and the diaphragm in place. They are yery well machined. Among other things, you can also see the long channel 'clips' that will secure 2 support structures that will come together to make one working panel. You will also find a roll of mylar film, wires and also tools.... yes it comes complete with tools!!
The machined support structure is the black plastic frame. The white strips that you see are the spacers that will hold the frames, stators and the diaphragm at the correct distance in relation to each other. The white spacers are glued onto the black support frame. A very elegant and but simple design.
And completeing the basic components that make up an ESL are the stators. These are the Steel Grids will be used as the the stators for the ESL. They are thin but sturdy and are finished in black powder coat.
The next Step.... I begin the build by Installing the Stators and Support Structure

Wednesday, December 12, 2007

DIY Electrostatic Loudspeakers / ESLs - Why and How...

Electrostatic Loudspeakers or ESLs have always been thought of as very esoteric speakers to me. They seem to work on very hi-tech scientific principles only known to a few people. It was also thought of as the spekers that only the very well to do have access to. This idea was probably bourne out of the knowledge of how much it costs to buy one. My early education on the topic started thus. Little did I know that the ESLs have been around since the early1900s.

Then in 2006, I had the chance to listen to a pair of Martin Logans driven by Krells at one of the Hi-Fi trade shows. The fact that during my visit to the Hi-Fi trade show, I returned to listen to this setup 3 times speaks volumes. While seated in the sweetspot the Martin Logan ESLs did a dissapearing act, the singer was holographically projected into the room. I was really impressed. The music was, well.... very nice. Vocals were liquid, instruments were accurate and fast. The only drawback was the coned woofer at the base of the ESLs, they made the bass sound disembodied, slow and woolly compared to the rest of the music... literally.

Well after much thinking, I decided that I was not going to afford the Martin Logans on my budget. So the answer for me was going to be a DIY project. After having researched the internet for DIY ESL projects, and after reading of many successes, I felt confident enough to start my own project. While the priciples ESL are simple enough to grasp, however, I do admit that I do not have the aptitude to design and build an ESL from scratch. Through my research, I have learnt of several ESL Kit provided by ER Audio of Perth, Australia. The ESL kits comes complete with all components that would be needed to build a complete pair of ESL, with the exception of the wooden frames/cabinets, you'd need to source and build the wooden frame that holds the stators in place by yourself. Detailed instructions are provided and the support from the ER Audio is superb to say the least. ER Audio is run by Rob and Jan Mackinlay. I cannot say enough good things about Rob and Jan Mackinlay, they are both honest and helpful, eveready to offer advise and assistance at a moments notice. The fact that they are really pleasant to deal with is just a bonus.

This project is not for the novice DIYer, but the procedure to construct the kit is "foolproof". I also had the oppurtunity to discuss the ESLs with several owners that have built the kit, and all have reported outstanding reliability and support from ER Audio. What's more, all owners report that the performance of ER Audio's ESLs are equivalent to or even surpassing the ESLs commercially available today.

For my budget and my listening environment, I chose one of ER Audio's kits that bore the designation ESL III. The completed speaker is adequate for a room up to 6m x 4m. It will go down to 35-38Hz @ -5/-6db. Larger rooms would require additional reinforcements. The price of the ESL III kit by my standards, are not cheap. But its is infinitely cheaper than the of the shelf offerings by major manufacturers. The ESL III kit consists of 3 panels, 1 treble panel sandwiched on either side by full range panels.

After much thinking, I placed the order in November, 2006 or there abouts. Rob the owner then proceeded to send me the build manual, so it gave me plenty of time to get acquated in the build steps. It takes about a month to manufacture all the items and pack them. The package arrived just after christmas and I started the build almost immediately. I have now had the ESL IIIs completed for some time now. How do they sound....well... all the superlatives that you have ever heard about ESL and their inherent strengths apply here. These speakers really do need a good quality source and amplification. At the moment I am using a 100watt Yamaha AV amplifier as well as an old trusty 35watt Musical Fidelity amplifier to drive these speakers. The Musical Fidelity amplifier injects much excitement to the music, but does not have enough current to deal with the ESL's quirky impedance. The Yamaha AV amplifier is much smoother and adds a warm touch to the music, but ultimately is not fully up to the task of driving the ESLs convincingly. As such I will DIY a 200watt amp to pair with these speakers. This new amplifier is based on Pass Labs Aleph 1.2 with very good current capabilities. Stay tuned

I am doing a posthumous chronicle of the build process for the ESLs in this blog. Have fun reading.... Start Here


Welcome to my DIY Audio journey

Hello and welcome to my DIY Audio journey. Why DIY Audio and why a journey?

DIY because the chance to make something functional with your own hands is reall satisfying. And to marry this with my love for music is just a bonus.

A journey because it is my believe that there are several goals in pursuing this "hobby", it does not really have an end point. The DIY journey is full of elation and also exasperation. Sometimes you get it right most time not....