DIY ESL

[bentoronto]

Still though imho ESL sound best when properly crossed over with an active Xover.

The input impedance of an ESL (which sometimes starts with a bit of EQ and minimum impedance protection ahead of the transformer) is all over the map from an ohm or two up to dozens of ohms. No way to divide the signal with a passive crossover with that kind of complex load where every element varies with frequency.


Hard to think of any application of interest to me where a passive crossover would make good sense.

Ben

 

[bengel]

Lots of good stuff in here.....

Active Vs. Passive Crossovers

(and sorry for hijacking the thread with my rants against passive crossovers )

 

[bentoronto]

One thing I don't understand is bass response: the lower frequencies sound tight but "thin". I really like the quality, but compared to the average electrodynamic loudspeaker it sounds thin..

I'm sure I've posted this a million times before: "flat" bass sounds thin. If you measured the homes of experienced HiFi fans (including acoustical music purists), you'd find the bass is cranked up some.

If you are able to get louder bass without destroying your speakers, try it.

BTW, another thing I've posted many times is my doubt that the textbook theory of dipole cancellation (rear wave annihilates the front wave) poorly characterizes the results in a real room where phases are wild due to reflections, baffles not perfect circles, etc.

Both are wannabee engineer errors. Basic theory is applied without understanding the subtleties.

Ben

 

[silvershadelynx]

Could you say something about the Mylar thickness, where you order the Mylar and also the sort of coating you used for this lovely ESL-build ?

Hi, sorry for my late reply, I've been busy with other activities recently.

I used 6 micron Mylar (PET) non-metalized film and bought it at a small Dutch company called Audio4 (Audio 4 elektrostaten homepage), it is 80 cm wide. But there's another Dutch stat builder (Martin-Jan Dijkstra) that, correct me if I'm wrong, sells 6 micron 100 cm wide mylar. The latter option would make it more easy if you want to get multiple stats out of one piece of mylar for equal tension, so I would recommend this option.

Because of high frequency roll-off I would go for 6 micron of smaller film, I think 6 micron is a good compromise between HF range and not tearing too soon?

There have been stat builders that used Hostaphan film, but I'm not familiar with it.

I used a coating made by Martin-Jan Dijkstra:

http://www.diyaudio.com/forums/planars-exotics/101787-membrane-coatings-martin-jay.html#post1209398

I'm happy with this coating - although I have no long term experience as my stats are only a few months old. It has a high surface resistance (Giga ohm range). I used an old version of the coaing - the bottle could be over 10 years old but it still seems to work well. It leaves a transparent thin (< 1 micron?) layer)

I used a (round) paint brush, but using an air brush could be a good alternative I guess.

 

[silvershadelynx]

Could you show us how you stretch your wires?

I'm not sure if I have pictures of the process of stretching the stator wires - but I used a very simple process: first I drilled holes in the frames; after that I hammered nails into the holes; after that I just stretched the wire around the nails - by hand.

With the bigger (wider) stators I sometimes had to remove (and re-install) a group of wires as it loosened during attaching different groups of stator wires as stator tension is increasing during attaching the wires.

Some builders pre-tension the stator by bending it before installing the wires, but I didn't do that.