New hybrid ESL Build

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Hi mavric,
thanks for joining in!
I've been reading all I can about this stuff... actually, I read your entire thread a few nights ago, the 33 page one. I learned a lot, Charlie's blog is very informative too. I plan on thoroughly documenting my build with lots of photos as well.
Can anyone tell me about the diaphragm thickness? My previous post...
 
What is the effect of the diaphragm's thickness? I see 6 micron film from TAC and also 3 micron on ebay. Is it simply a matter of thinner is better because of less mass up to a certain point where structural integrity gets compromised? In other words, if it's too thin then it could break too easily?

Maybe some one who's used the 3 micron film will chime in-- but since no one has, I will comment about 6 micron film.

As I said, I've only used the 6 micron film but your logic sounds about right to me. That is; at some point the mass of the film will limit the high frequency response-- the heavier the film, the lower the roll off point. Hence, 3 micron would be most accurate for highest frequencies. I don't know the roll off frequencies for the various weight films but I can attest that 6 micron is adequate beyond beyond what most of use can hear. I've heard that Martin Logan uses 12 micron film because it can be tensioned higher; so, how bad can 6 micron be, eh?

I know from working with 6 micron film that it's tricky to handle-- extremely strong in tension, yet it tears all too easily if you stress it along an edge. I use very sharp scissors to cut it off the roll so I get a smooth cut edge with no place for tears to start and then I handle it with the utmost caution. I suspect that the 3 micron film would be even tricker to handle and install but I doubt it would be prone to breaking once it's successfully attached to the stator.

I'm looking forward to hear the impressions of anyone who's used the 3 micron film-- so come on and chime in here, you guys!
 
Hi,

I do not have any test measuring done. I only use my ears. I have tried 6, 3, 1.5 and 0.8 microns films with my headphones, and I like the 3 microns Mylar the best.

On my current ESL, I run them full range. I tension the 3 microns Mylar upto 1.5% elongation. My stretcher is exactly like what Charlie is using. I feel that I have all the bass I need without the need of using an extra subwoofer. As for mids and highs, I have nothing to complain about them. :)

Wachara C.
 
The lesser treble in 6 or 12 my films is compensated for by the simple Peter Walker Law, which says: 5 mA ac in, 100 dB out. This applies for the perfect (theoretical) Esl of any shape or stator/stator distance. But we can use in practical Esl:s also, i.e with rising frequency in an Esl, the impedance lowers, the current increases and so does the output..this is why M-a-r-t-i-n L-o-g-a-n-s with 12um metalized membranes can play treble.
 
I've worked with both 4 micron and 6 micron tensilized Mylar films.
While 6 micron is somewhat more robust, the 4 micron tensilized Mylar® turned out to be strong enough for all of my applications. In fact, using the very thin ones may prevent you from achieving a film which is stretched too tautly (too high resonance frequency).
Sonically, the 4 micron offers very smooth sound without sounding harsh. On the other side, 12 micron, sounded more like a (though good) dynamic tweeter. (12 micron feels like a thick cracking chips bag, 4 micron is more like a thin sandwhichbag)
 
Thanks for reading my post, there are many more pics that I did not have time to post or time to explain. Charlie and I use basicly the same setup, his are taller and not as wide, as mine are short and fat.
Being that way opened the sweet spot alot, and i mean alot. At or about 15 feet away, three people can enjoy encredible sound without one sounding louder the other.
It also may have to do with your area you plan on putting your panels,as I have read and understand, the bi-pole has it pros and cons, Charlie has a flat ceiling as mine is vaulted. At first I tried his posistion and did not work. Since i am in the car audio business, i had plenty of high grade wire to move them, the sound is something you cannot describe, you can talk about it all day, but when you build something unique, that has such sonic, fast and VERY accurate tones, I will say, I cannot wait to get off work just to listen. And not even in the sweet spot, they play throughout my home with such clarity, even turned allmost all the way down. You can talk on the phone while playing, hear every detail, but it does not interfere, like, you dont have to yell or say "what or i cant hear your" . spectacular.
These are just a few of the things I have noticed over traditional coned speakers, which I deal with on a daily basis. Good luck and please go for it! I will never forget this experience. DIY, there is nothing like it.
Kind regards, Mav
 
I am already entertaining the idea of buying enough extra material to make a small set of hybrid ESLs to mix on for my recording studio. I'd like to know what the effect of downsizing the panels would be. I think the the idea of a tight "sweet spot" is not a problem when mixing because I'm always sitting in the sweet spot. Also it would be a nearfield monitoring situation with my ears no more than 3 or 4 feet from the speakers. I should also mention that I rarely monitor over 95 db. Typically 85db.
Any recording / mix engineers here? Anybody ever try this? I just wonder because I have never, ever seen ESLs in recording studios.
 
Hi,

downsizing shows several effects, depending on what You downsize.
Since for a given SPL the air volume which has to be moved is known, You can trade -within limits- membrane area against excursion.
Since the maximum excursion needs to be lower than the d/s this means an increase in d/s with all its negative effects. First to mention is lower efficiency, which is countered by a higher transformation factor of the audio tranny. Quality-wise and sonically a lower transformation factor is desirable. You can of course increase the crossover frequency and keep a small d/s, but this will put a greater part of the frequency range on the dynamic mid-bass. The higher the crossover frequency the more of the ESL´s "magic" vanishes. A small ESL sounds like a fairly good tweeter. I´d say that a crossover of no higher than 400Hz preserves the ESLs outstanding qualities.
The building effort for a small or a large panel is nearly the same. Downsizing increases the needed overall building effort and opens room for failures and tolerances.
Downsizing might allow to use materials which have a certain dimensional limitation. If You for example think about PCBs as stator material You will be size restricted to less than 600mm and it allows for the combination of differently shaped and dimensioned panels that work over different frequency ranges (more about this later).

In Your special situation of a fixed and relatively small distanced listening position a tall and thin ESL wouldn´t be optimal. I´d opt for a wider and less high panel, maybe even quadratic dimensions. The wider panel suffers to a lower degree from acoustic phase cancellation than a thinner one. This allows for a lower degree of equalization or lower crossover frequency. With a panel that wide (suggestion: ~600mm) You should use electrical segmentation or curving. Electrical segmentation would have the advantage that You are not restricted to a one-dimensional shaping of the distribution character. It would allow for not only a slightly widened horizontal distribution, but a vertical too, similar to the Quad63 but without the complex and rather useless delay line nicknack.
The distribution character would be dipolar lobed which is closer to the monopolar (or single lobed) character of a partnering midbass.

When You opt for a multi panel ESL how´s about this idea:
A H-shaped combination of 3 panels. The - part of the H would be a quadratical shaped upper-mids-high panel with small d/s and 2, maximal 3 circular or oval segments to control dispersion. The left and right leg could be 2 panels with slightly greater d/s supplying for the range from lower- to upper mids.
2 dynamic bass drivers could be put between the legs of the H. Similar to the D´Appolito design the bass drivers wouldn´t be too far apart from each other and the 2 side-panels increase the membrane area to the needed size. Beeing a Monitor for close listening conditions the ESL´s sound radiation to the rear could and should be strongly dampened. A cabinet rather deep and open to the rear and with two ´internal´ pyramidal shaped bass cabinets. So the ESL could be part of the complete casing. It would omit with the dipolar character which would be disturbing in te described situation anyway. The monopolar lobed distribution character of the ESLs easens the crossing-over-/seamless-integration-problem to the basses. Measurements need to be taken though to insure that the ESL diaphragms would not be blown into the stators by basswaves. The concept would allow for close-wall positioning. Electronics would be more complex because of different transformation factors and polarizing voltages for the panels. Preferrably the system would be driven active or mixed active/passive.
Possibly something like this:
Nearfieldhybridmonitor

jauu
Calvin
 
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Hi,

build it quickly in my mind. You know I´m Calvin....Interplanetary Explorer Extraordinaire...on a mission of weird thinking. ;)
No, just kiddin. Just thought a bit about what a mixing monitor in a close listening distance situation might demand. I haven´t checked the thoughts on sensibility or practicability. So hit me with Your death blaster desintegrator ray. :p

jauu
Calvin
 
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