2 Small Panels or 1 Large One - ESL

[audio.ESL]

Just wondering how to choose the correct size of ESL panel.

Option One - 1800MM * 300MM Panel for one ch.
Option Two - 2 1200MM*300MM Pancels for one ch.

If we use the same material,HV bias,spacer and step up transformer,is there a big difference of frequency response between both?

I just finished my first prototype and found it's much easier and cheaper to build the 1200MM*300MM panel.In fact,I am still looking for a big table to build the 1800MM*300MM panel.

[Calvin]

Hi,

just one panel, but make it less high and more wide, e.g. 1600x400
two panels just means increased building effort without any advantage against a single panel.

jauu
Calvin

[a.wayne]

Hello Calvin ,

Curious , why would you want a shorter panel ?

regards,

[audio.ESL]

Originally Posted by Calvin

Hi,

just one panel, but make it less high and more wide, e.g. 1600x400
two panels just means increased building effort without any advantage against a single panel.

jauu
Calvin

Thanks for your suggestions.
If I connect two panels in parallel mode,how about the frequency response change? I am afraid that the bass response is not enough.
It's easier and cheaper to buy smaller stator sheet like 300MM*900MM.

Thanks.

[Calvin]

Hi,

why shorter? Well, exactly I said shorter but wider. A panel of say 120cm height is alrady so high, that You can listen to it sitting as well as standing (if You want to mount it so). Such a panel will show it´s maximum SPL at a distance of 2.5-4m which is a common listening distance. A taller panel would show its maximum at greater distances.
The acoustic phase cancellation (apc) depends on the shortest dimension of the panel, which is the width. With a 30cm wide panel the apc will become effective below ~800Hz. Increasing panel width reduces the effect towards lower frequencies. So less equalization would be needed for a wider panel. Simply increasing width on the other hand would increase the panel´s area and so the capacitance and makes the panel a more difficult load to the amp. Above 1nF of capacitance transformer design becomes more difficult too. So to keep panel area and as such its capacitance below a certain value you trade height against width. ;-)

jauu
Calvin

ps: A FR-ESLs bass response will almost always not be ´enough´ if You ask for prime quality. But that´s my personal view ;-)

[Capaciti]

Hi,

i do not agree that any short panel is OK, depending on the listening distance.

There are some rumours saying panels get louder with increasing distance. I do not know, how this should happen. And nobody supported this statement by measurements.

I build more than 400 Pairs of ESL over the last 25 years and i can tell you, that any panel, independent from height lost sound pressure with increasing distance.

If you want most of the sound provided to your listening position without disturbance by room reflections ( and this is the main goal in typical living rooms) you should prefer cylindrical wave radiation. In best case you can achieve this radiation to lowest frequencies as possible and this is the reason why long panels easily outperform short panels.

E.G. a 180cm long panel will provide cylindrical radiation down to lower than 100 Hz.

Capaciti

[chinsettawong]

Hi Capaciti

Will stacking 2 short ones vertically result in the same as one big panel?

Wachara C.

[Capaciti]

Hi Chinsettawong,

basically yes !

Acoustat did it, Pütz did it, Quadfreaks stack their 57er three times......

There is a little compromise when stacking, since the arearless borders from one to the other panel will create the venetian blind effect, causing sound interferences, but this is limited to shorter linstening/measurement distances.

If stacking, borders at ear level height should be avoided (70 -110cm from floor)


Capaciti

[a.wayne]

Hello Calvin , Capaciti,


Thanks for explaining your positions on the above , both explanations seem reasonable and based on my experiences , Like Capaciti , I do prefer height over width, but this will require wings to archive any reasonable cut off below 400hz , Hence Calvin's comment on width. I have found it better to use wings for cut off than to have a wider panel vs height.


We also spent many hrs Last month , where a group of us have been comparing curved ESL to flat ESL and flat was better every time hands down, well at least in our setup and dedicated listening room.

regards,

[Capaciti]

Hi Wayne,

your way is my favorite as well.

Make it as tall as possible, the width of membrane area should not exceed 20cm's, otherwise you will get trouble with mechanical stability, when uisng small D/S spacing.

Its better to add asymmetrical wings, lets say one third to two third width. Off axis interferences will be smoothed, resulting in better sound dispersion to the room.

Your overall bafflewidth should be at least 50cm. Than sound cancellation will start at 400 Hz, which is your crossover point.

Capaciti