where to purchase foil on film?

[thadman]

Where would I go about purchasing some copper imprinted on mylar, somewhere on the order of 3-5 microns thick (or lower if possible)?

[JonMarsh]

IF you're considering doing an ESL, you need to research some more concepts, especially that of charge controlled diaphragms. I really, really think you don't want copper on mylar.

There's been a lot of DIY stuff on ESL's published since the early 70's- have you read much of it yet? No point re-inventing the wheel.

~Jon

[cotdt]

actually, i think he wants to roll his own foil inductors?

[thadman]

No, Jon is right. I was considering a quasi ribbon (think magnepan). I guess I dont care about dynamics as much as I care about fidelity I wont be listening to it at realistic volumes anyway.

Never heard of charge controlled diaphragms...care to provide some links? I googled and didnt come up with anything.

Wouldnt the planar magnetic sound better than an ESL because I could power it with a traditional amplifier and toss out the transformer.

I have Rogers Sanders book (although...I am having trouble locating it at the moment) but if I recall it doesnt offer any options to avoid intense directionality other than multiple dedicated panels or a single very narrow panel. These both conflict with my design, because I NEED to reach 250-300hz for a crossover point (large surface area for displacement purposes) and I'd like to run it fullrange for obvious benefits (less crossover work, less $$$)

Im planning on using multiple EP2500s for the dipole bass array (40/50-250/300hz) and infrasonic bass (10-40). Would I be able to use one of these...or would it be highly recommended to go with a different amplifier and if so what would you recommend?

[jdybnis]

Take a read through the ESL form on diyaudio.com. A bunch of guys there have success with building ESL's and they can help you out with the practical issues like sourcing materials.

http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=54

[JonMarsh]

Foil covered mylar should be sourcable for a planar magnetic tweeter, but it's going to be aluminum, not copper- copper oxidizes into non-conductive stuff, doesn't work well at all compared with aluminum.

[cotdt]

doesn't the capacitance of ESL's destroy most amplifiers?

[Evil Twin]

Well designed ESL's should have no problem being driven by well designed amplifiers- therein lies the criteria.

ThomasW has been using Acoutat 1+1 as midbass panels for over 10 years, with no issues with amplifiers or speakers. High quality driving transformers are available from some DIY sources as well as Plitron. Inductive reactive loads can cause amplifier failues just as likely as capacitive from SOA issues- but marginally stable amplifiers will self oscillate and destroy themselves with some electrostatic speakers.

[cotdt]

Well designed ESL's should have no problem being driven by well designed amplifiers- therein lies the criteria.

ThomasW has been using Acoutat 1+1 as midbass panels for over 10 years, with no issues with amplifiers or speakers. High quality driving transformers are available from some DIY sources as well as Plitron. Inductive reactive loads can cause amplifier failues just as likely as capacitive from SOA issues- but marginally stable amplifiers will self oscillate and destroy themselves with some electrostatic speakers.

hmm, so I see you have to use transformers. Doesn't the transformers add a lot of distortion, though?

[thadman]

Would a planar magnetic be preferred over an ESL, since it doesnt have to use a transformer? Im assuming the RD75 is a planar magnetic, could a DIY version get down to 300hz @ 48dB?

[thadman]

How much excursion at the very bottom end could I expect? 1/.1/.001mm?

[cotdt]

the electrostatic membranes used in certain headphones can actually play deep low bass with excellent extension, so i'm sure that for very low output levels, you can cross quite low with them.

[gvinson]

The RD75 can reach your objective.

[gvinson]

I forgot to mention...you can buy the aluminum deposited mylar from Dave Sauter at carveraudio.com.

[thadman]

How much displacement could I expect from an ESL? Im assuming 1-2mm with the correct stator spacing, am I wrong?

The RD75 ive heard sounds best 600hz(displacement limited)-6000hz(directionality limited) and are quite expensive (cheapest I could maybe get them if I got lucky would be 1000-1200 a pair).

I'd like to build a single transducer that can handle 250/300-20khz with extreme fidelity, be able to work with cheap amplifiers (I've already got a Crown XLS-402B can provide an EP2500 if necessary), provide 110-115dB of uncompressed dynamics, and provide enough off-axis energy so that I dont feel like my head is in a vice when im listening to them.

I've got ~$1000 (maybe a little more) to build the transducers, and have access to all the machining id need and sourcing of parts (friend works at a machine shop). I can also get a pretty significant discount of neodymium.

What transducer technology should I incorporate? Ribbon? Planar Magnetic? ESL? After modeling it in linkwitz's spreadsheet im going to need roughly 26.7cm^3 of displacement at 283hz to reach 115dB on a 30" baffle (~16-18" of this is going to be dedicated to the RS390HFs)

[gvinson]

Just a clarification....the RD75 can meet your objectives on the lower end of the scale, whether it is effective on the top end - I cannor answer. I apply a very small amount of eq to the earlier RD57 above 16khz and am quite happy, of course that is blashemy, but I don't care.

A crashing symbol in my listening room sounds like a crashing symbol, full of dynamics and decay. Being a percussionists, I have my internal standards for realism, but that doesn't mean that they meet the standards of the group.

If I were just starting out on this voyage, I would play close attention to what Thomas W, Jon, and AJ have to say on the matter.