Horn loaded electrostatic ??

[brsanko]

Well I started this thread and my intention was to increase gain. A horn typically narrows the dispertion and increases beaming in higher frequencies in dynamic drivers but by using a narrow throat and wide mouth I suppose it could possibly improve upon an ELS. My question to bolserst is; does an ELS typically reach arching before it reaches it's excursion limit?

[Calvin]

Hi,

Mark reminded of the imho one deciding factor a Horn is all about....impedance matching. The Q arises as to why the Horn works for Dynamic speakers as Driver and why it may work differently or not with an ESL. Imho the answer depends on the ESLs dimensions.
If build with appropriate dimensions the acoustic impedance the panel sees can be made real, the optimum situation. Dynamic drivers are usually working under complex conditions and the Horn increases the real part of the acoustic impedance, hence the efficiency of the coupling of the diaphragm to air. A horn could only be helpful to a small Panel. But the horn would counter the smallness and increase dimensions. A large panel on the other hand is best without any kind of baffle. The double or multiple diaphragm panel really increases the SPL because of increasing the force per unit of area.

Jauu Calvin

[markusA]

I only had time to skim the last couple of pages but one thought struck me as interesting.
If the horn was to lessen the ESL excursion as a result of horn loading, wouldn't that be sort of the holy grail?
We're always fighting high voltages and large D/S. If there's a way to keep the spl up, reduce the d/s and thus reduce the voltages it would seem like worthwhile to me?

I might have missed something important and will re-read the pages later this evening. This was just a spontaneous reflection on something bolerst wrote.

[bolserst]

Originally Posted by markusA

If the horn was to lessen the ESL excursion as a result of horn loading, wouldn't that be sort of the holy grail? We're always fighting high voltages and large D/S. If there's a way to keep the spl up, reduce the d/s and thus reduce the voltages it would seem like worthwhile to me?

Keeping D/S down while increasing SPL output is indeed a tough proposition for low frequencies. The horn can help with this for a given panel. But, if you move your panel from the throat to the mouth of the horn, increase the panel size to that of the mouth, and get rid of the horn…you will have the same max SPL capability with the same reduced excursion as for the horn loaded smaller panel. The frontal area would be the same in both cases, but the horn would add considerable depth.

Originally Posted by brsanko

My question to bolserst is; does an ELS typically reach arching before it reaches it's excursion limit?

Of course it all depends on how you design it. Most ESLs do arc or form corona before reaching excursion limits. But some designers/builders choose to use smaller D/S spacing than is needed for the LF bandwidth of their ESL panel. Usually, this is to allow the use of smaller/cheaper transformers and amplifiers to reach peak output in the midrange. It doesn’t make sense to me because you can only play them loud when playing music without heavy bass content. But, not everybody has the same priorities.

The key point to remember is that the max force per unit area is not dependent on D/S spacing. It is dependent on voltage gradient in the gap. Choose the D/S required to keep the diaphragm from hitting the stators at the LF bandwidth limit you desire, and this dictates the bias voltage and stator drive voltages required to reach the max force condition before arcing.

Originally Posted by geraldfryjr

I know that we have discussed many different methods to combat this issue,But I am still curious as to if a horn might be a viable alternative at least for the midrange frequency's and up.

For midrange and up where ka>3 (ie wavelength is considerably smaller than the smallest dimension of your ESL panel) the airload the ESL “sees” will be resistive in nature and horns will provide gain as expected. But, remember that all ESLs have by nature a response that rises with frequency. So, if you boost the output of midrange and higher frequencies with a horn you will have a more difficult time getting an ESL woofer to match up in output capability.

[mwmkravchenko]

I think I understand what you are getting at, let me try and restate it to check.

bolserts Yes you understand.

Calvin yes you have it right to.

See below to have your cake and eat it to.



Well you guys remind me of the ESL fundamentals and in a different thread there was a sketch done of a larger panel stack with a side exit. That would provide enough air velocity from the electrostatic panels to take proper use of the horn loading.



Keep this in mind that in an optimal horn the air is pressurized and basically behaves as a fluid right off of the area creating the pressure front. So you could create a panel stack that exited out on edge, much more conducive for horn loading.

Horn I understand well.

The second problem always inherent in the horn loading dilemma is that a large throat area is not conducive to a good horn design.

The thin side exit stack idea would solve that problem to.

I have a few clients that would be interested in this if I could get it working. Heck I would be interested if I could get this working.

Time, more time!

[bolserst]

Originally Posted by mwmkravchenko

Well you guys remind me of the ESL fundamentals and in a different thread there was a sketch done of a larger panel stack with a side exit. That would provide enough air velocity from the electrostatic panels to take proper use of the horn loading.

Keep this in mind that in an optimal horn the air is pressurized and basically behaves as a fluid right off of the area creating the pressure front. So you could create a panel stack that exited out on edge, much more conducive for horn loading.

What you are describing (...large panel stack with a side exit...) is an ESL AMT(Air Motion Transformer).
I’m guessing you may have seen some sketches in the Electrostatic AMT thread:
Electrostatic AMT?

Attachments #1 & #2 are some figures pulled from US patents 3,008,013 & 3,136,867.
Attachment #3 is a drawing of a stator-less AMT posted toward the end of the AMT thread.


What do you think the advantages would be to horn loading an AMT vs. the AMT by itself?
.

[mwmkravchenko]

yes the one on the right is the sketch I was remembering.

The center diagram looks interesting. As does the left most one.

So we are not the first to have thought of this?

Hah.

There is nothing new in audio.

Only better materials in some instances.

This is looking more feasible as you show examples.

Depends on my work load , but I think I will give this a try.

I'm only four designs behind right now.

[brsanko]

Well if a horn would work well for a smaller diaphram but would end up being larger than a larger diaphram, I guess I wonder if perhaps it would be cheaper.