Finished ESL picture (finally!)

[Mallickarjuna]

Dear MR,

How does one calculate the required size of the ESL, let us say I need to operate between 100Hz to 20KHz, does the width and height matter or just total area?

I could not lay my hand on an DIY ESL book, where can I find more technical info on the website?

Is it possible to make our own audio transformer?

Thanks in advance.

[MRehorst]

For bass to 100 Hz without a lot of equalization you need to make the thing 24" wide or maybe a bit more. That means the driver itself should be 24"wide or the baffle with the driver mounted in the center should be about 24" wide. The height should be at least the same as the width- i.e. the 24" is the minimum dimension of a rectangular driver/baffle.

Look for Roger Sanders' book on ESL at Amazon.com
Also go here ESL Circuit

It is possible to make your own transformers, but determining what materials are needed (the core) and obtaining them is going to be a real challenge. Winding transformers, especially high performance audio transformers, is a bit of an art.

MR

[stokessd]

Very nice work...

Did you do any measuring of your speaker? I'm currently working on a smaller ESL and I'm using a pair of Fisher (x-100) transformers run backwards much like what you did with your transformers form antique electronic supply. The fisher's have the typical reactive peak that all transforms have driving reactive loads, but the fisher peaks pretty low; in the 13K range.

Are you running them full range? What are you doing about pressure feedback?

Sheldon

[peterr]

The stretcher you used is a variation of the metal bars with screws that Roger Sanders used in his Speaker Builder (or was it Audio Amateur?) articles many years ago. I tried it and discovered that since the metal bars will flex, you always end up putting lots of tension on the corners of the film and very little at the center. This can be seen when the diaphragm fails because of over tightening -it is always split along the corner-to-opposite- corner axis

I have used something very similar to stretch my mylar. but I first stretched it in only one direction ( top to bottom) and only after that I taped it to the sides of the streching table and stretched it left to right. It worked fine and as far as I can tell very evenly.