Other ESL build with simple materials available from local grocery stores

[Audio_idiot]

Hi,

Thanks for sharing you experience.

On the cureve plate, do you have to make a curve form to hold the stator in shape. I couldn't convince myself that the shape will hold by it self... A part from this, I feel that curve panels are really any more difficult to construct then a flat one...

Another very stupid question,
Does the nerrow dispersion of the ESL really matters in small listening areas?

Cheers

[I_Forgot]

Some like to argure otherwise, but my experience with my self-built flat panel speakers and my Quad ESL-63s is that the narrow dispersion afforded by flat panel speakers results in better "imaging". The drawback is that the sweet spot really is a spot, but that spot is a slice of heaven. When listening to speakers with wider dispersion (such as the Quads), you're less likely to hear complaints from people who aren't in the spot, but even in the spot, there is some reduced imaging and transient quality, I suspect due to multipath resulting from wider dispersion of mid and high frequencies. There may also be some effect due to the aiming of the speakers at the ears. The left ear, slightly off axis with the right speaker, will experience a slightly different frequency response for the right channel, and vice-versa.

A flat speaker with nothing done to broaden dispersion has a predictable frequency response- 6 dB per octave rise in level if I recall correctly. This is very easy to make a filter to flatten for on axis listening. As soon as you do things to broaden dispersion, if you do it sucessfully, you now have a more complex on-axis response pattern to try to even out.

I_F

[Calvin]

Hi,

there might be a positive effect with a strong curvature (btw. ML used to use 30°, i.e. +-15° on older panels. The new panels use less curvature) but You might experience greater problems when mounting the film. Stability of the panel is increased substantially even with such a slight curvature. It will be strong enough as soon as the panel is fixed along its sides with a mounting frame. I use an aluminium profile that has an 10mm wide slot in which the Panel (~6mm thick) is pushed. Between panel and slot walls is a layer of damping foam.

The process of curving is imo the easiest and cheapest way to improve stability! There is no time consuming or extra costing difference in the other building steps. So the choice is to curve the sheets, which is done in a few seconds on a machine, or to fix some bracing elements onto at least one stator (how for example?).
ML´s choice was the curved stator since ML not only built good speakers but speakers with terrific looks and lowest production costs.

Sonically there is a difference between panels where the complete film area is driven (wether they feature a curvature or be they flat) and panels with electrical segmentation. Dynamics in the upper freq-range improve with complete panels, but it will cost seriously in the distribution character department. Imho the sonic result is a matter of taste. I like the strong dynamics of a complete panel, but since I wasn´t prepared to fix my head on a tiny little spot area I curved the panel to give at least a slightly better dispersion. So for me curving payed off twice If You want at least a second person to have a good listening, You have to care for the distribution character of the panel.

jauu
Calvin

ps: simple etching just puts off material of the sheet, so sheet thickness will be reduced and hole diameter rises generally. Electropolishing on the other hand works best at sharp edges and small points (the points of hig filed strength). All etching processes have the advantage that the surface area becomes bigger and that the bond of the coating to the stator improves.

[MJ Dijkstra]

I made a curved wire stator with a curvature of + and - 30 degrees, so 60 degrees total and it matched the curvature of the sequel2, so I think we have 60 degrees total indeed.

I don't know about the newest models like the vantage and the summit since I haven't seen them in reality.

Cheers,

[Capaciti]

Hi,

i think there are always arguments pro and con dispersion.

For my experience it need to be a combination of both dispersion options.

The segmentation of my flat panels is optimized in such way, that dispersion is very good between +/15° and decreases rapidly at higher angles.

The mentioned better image of narrow dispersion panels has nothing to do with the dispersion itself, but with the interaction of early room reflexions. As long the dispersion is limited to avoid early reflections, preferably from side walls, it should have identical image.

On the other hand the discussion need to consider the frequency range we are talking about. I would say that all ESL show comparable dispersion up to 2 Khz and just differ at higher frequency. And high frequencies will be better absorbed by air, thus minimizing wall reflexions.


capaciti

[Audio_idiot]

Hi,
Thanks guys,

Looks like dispersion is up to individual taste... No quarms with that

Curve plate will definately stiffen the panels, but my question is the how well will the stator hold up its profile during construction? please do elaborare more.

I really like the idea of curve panel, I am tempted to make a tube to hold the panels, and the cavity behind the panel (in the tube) can be filled with fibre..etc resistive materials to absorb the back wave. Like a vented box... the looks is appealing (to me at least)What do you think?

Cheers

[Calvin]

Hi,

MartinLogan manufactures curved panels by the thousands.
1mm thick sheets are already quite strong and there are no such great forces while manufacturing that the curvature could be endangered in any way apart from maybe stomping on them

I strongly recommend not to use any kind of box or chamber.
One of the biggest advantages of an ESL is that You can get rid of it, because every compartement is an unwanted energy reservoir. And thats audible!
Since an ESL is constructed -and works- different to a dynamic driver, the demands for an compartement differ significantely anyway.
PJ Walker gave some hints of what could be used in praxis -and those compartments definitely look different - but as we know, he never gave up on building open/boxless ESLs, for thats the best way to build an ESL.

jauu
Calvin

[Audio_idiot]

Hi,
Thanks for clearing that out.

Another question, when you mentioned 15~20degree, that is 15~20degree dispersion off the axis? to phisically the panel will cover double off that?

And the panel width can be same as flat panels considerations without any additional considerations?


Cheers

[wolf_moses]

Roger Sanders' ESL book states it is very hard to keep the diahragm parallel to curved stators, as over time it will tend to be pulled into the back stator, causing non-linearity. I'm sure manufacturers can get around this, but what about the average DIYer?

[Calvin]

Hi,

there are quite a few mistakes and failures in Sanders Book.
The one about curving is imo one of those ;-)

jauu
Calvin