If you had a lot of ESL panels.... - Page 3 - diyAudio
Go Back   Home > Forums > Loudspeakers > Planars & Exotics

Planars & Exotics ESL's, planars, and alternative technologies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th August 2013, 08:24 PM   #21
diyAudio Member
 
Join Date: Jan 2008
Location: Toronto and Delray Beach, FL
Quote:
Originally Posted by bolserst View Post
With a finite rather than infinite segmented wall, there will be left and right boundaries to the listening area(shown in the figure) you would need to stay inside of for the image to stay centered in front of you. The listening area boundaries narrow as delay is increased and the angle of the virtual sources are spread further apart. Also, moving further away from the wall of ESLs narrows the left and right boundaries of the listening area.
But as you move off to the left, isn't L getting louder and earlier? Isn't the delay (and distances) making things exactly worse? (Isn't that what "toe-in" of speaker boxes tries to over-come?)

Ummm.... just occurred to me: didn't Walker feed from the centre on the Quads (for frequency and beaming if not for spatial image reasons)? That would change the whole analysis.

Ben
__________________
Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), mixed-bass Klipschorn (28-110), and giant OB using 1960's Stephens woofer (18-110); Behringer DSP. HiFi aspirations since 1956
  Reply With Quote
Old 5th August 2013, 08:34 PM   #22
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
Beaming occur's when the frequency emitted is less than one half wavelength of the width of the Panel, Diaphragm or Aperture that the wave front is being emitted from.

It is a spherical wavefront (cylindrical for a line source) up until that point and as the frequency is raised it starts to become a focused beam.

As the frequency gets higher the beam gets more focused and narrower and also some side lobes start to develop as well.

For instance for a 6" wide panel this transition starts at Aprox. 1Khz and as it approaches 2Khz where 6" equals one wavelength the pattern then becomes a figure 8 (doublet) pattern.
I have shown this in some simulation's here,

A Segmented Stator Desktop ESL

The idea of putting them in a AMT fashion is it to increase the displacement for the lowest frequency's while maintaining a small floor area.
Second, having say 1/2" to 1" (or even maybe up to 2") aperture width helps to maintain a even cylindrical wavefront as the frequency is raised.

There is also a transition that occurs due to the depth (in your case 6" to 8" or so) but I forget the details, But it is explained in one of the AMT threads concerning pleat depth.

I would like to explore this more sometime when I finally get enough panels made.
It will be very labor intensive but I think a decent bass system could be realized with such a system and not take up too much floor space.
I think just 8 panel's or so may be enough to get good results.

Right now it is all just theory and I have yet to see a working system as such, But there have been patents and many discussion about this type of approach.

jer

Last edited by geraldfryjr; 5th August 2013 at 08:45 PM.
  Reply With Quote
Old 5th August 2013, 10:57 PM   #23
diyAudio Member
 
Join Date: Jan 2008
Location: Toronto and Delray Beach, FL
Many thanks for links (and I browse at that nice emerging forum too). Good bed-time reading for me.

Alas (and here my own professional biases begin to show), that's the birds' eyes views. But what if you were to ask, "What helps or hinders my perception (or localization or tingle or enjoyment) of the sound of the English horn slightly right of centre and halfway back?"

The defect of beaming in ESLs (like the defect of longitudinal torque reaction on my BMW motorcycle) is obvious to everyone except owners after a few days experience, let alone 35 and 45 years respectively.

That's not a quibble: the dramatic lobe-filled polar charts really bear little relation to sound at a listener's chair and the perception of a speaker. Imagine that you or I made a drawing of our perceived polar response.

Must be less cumbersome ways to do what an AMT is supposed to do, however worthwhile the goal might be.

Ben
__________________
Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), mixed-bass Klipschorn (28-110), and giant OB using 1960's Stephens woofer (18-110); Behringer DSP. HiFi aspirations since 1956
  Reply With Quote
Old 6th August 2013, 12:17 AM   #24
diyAudio Member
 
bolserst's Avatar
 
Join Date: Jun 2005
Location: Fort Worth, Texas
Quote:
Originally Posted by bentoronto View Post
But as you move off to the left, isn't L getting louder and earlier? Isn't the delay (and distances) making things exactly worse? (Isn't that what "toe-in" of speaker boxes tries to over-come?)
Short version:
getting louder = no
getting earlier = yes


Long version:
Sound intensity will be independent of distance from the diaphragm and always in a direction perpendicular to the wave front. Basically you are in the near field of the ESL at all positions. Having never build a full-wall ESL I haven’t experienced it. But I do know that a floor-to-ceiling line source provides a near uniform sound when my head is moved above and below the middle of the panel, and the image stays right in front of me(perpendicular to the panel) as I move my head up and down. If the panel is tipped forward or backward, the image shifts by the same angle. Yes, moving away from a line source and the sound intensity falls by -3dB for doubling of distance. But this is only because sound is spreading out to the left and right rather than being contained as it is top to bottom in a floor to ceiling beam. If the width of the ESL line source is expanded wall to wall as well, the wave front will not spread out in that direction either and intensity will be independent of listening distance.

NOW, concerning distances to left & right wave fronts when you move away from the center position:
Ooh! Excellent point! Apologies for being slow on the uptake. In a worst case situation with the listener positioned on the right hand edge of the right wave front and at a close 2m listening distance, the left wave front would arrive on the order of 1mS after the right wave front. So, while direction and intensity are properly retained at off center positions(as Walker states), timing between the channels is not(which Walker doesn't discuss).Certainly less than optimal for the top-shelf imaging you probably have in mind, except on axis.
Soooo why did we build this wall sized ESL? Move along, nothing to see here…


I'm not sure that toe-in of box speakers relates to this. With the polar response of box speaker in mind, generally toe-in is used to juggle first arrival frequency response and lateral reflections to provide the best perceived tonal balance and image with a sense of space and specificity.


Quote:
Ummm.... just occurred to me: didn't Walker feed from the centre on the Quads (for frequency and beaming if not for spatial image reasons)? That would change the whole analysis.
Yes, ESL-63s have concentric rings fed from the center with delay between the rings configured to produce a 2D curved wave front to emulate a point source positioned about 40cm behind the diaphragm. Similar to the wall-sized ESL, there is a boundary beyond which the point source emulation fails and the panel beaming behavior reverts to something more like that of a panel the size of its central ring.

Last edited by bolserst; 6th August 2013 at 12:19 AM.
  Reply With Quote
Old 6th August 2013, 01:24 AM   #25
diyAudio Member
 
Join Date: Jan 2008
Location: Toronto and Delray Beach, FL
Bolserst - thanks for one more highly informative clarification.

But one thing you said seems to defy the Laws of Physics, at least those laws known to earthlings with high school physics: "Sound intensity will be independent of distance from the diaphragm."

Is that right? Not even 3dB loss....?

Ben
__________________
Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), mixed-bass Klipschorn (28-110), and giant OB using 1960's Stephens woofer (18-110); Behringer DSP. HiFi aspirations since 1956
  Reply With Quote
Old 6th August 2013, 03:55 AM   #26
diyAudio Member
 
bolserst's Avatar
 
Join Date: Jun 2005
Location: Fort Worth, Texas
Quote:
Originally Posted by bentoronto View Post
But one thing you said seems to defy the Laws of Physics, at least those laws known to earthlings with high school physics: "Sound intensity will be independent of distance from the diaphragm."
I guess there are two ways to look at this:

1) From Walker's perspective the wall ESL at one end of a room could be thought of as a piston connected to the end of a pipe. Sound waves travel down pipes with very little loss. Granted the room is a very short pipe, and as Walker mentions requires a large amount of damping at the end to avoid reflection and standing waves. But, there will be very little loss traveling down the "tube" from one end of the room to the other.

2) Looking at the ESL alone without any walls around it, you would still have a flat response independent of distance as long as you are in the near field.

The formula for determining near/far field transition relative to a panel dimension is:
F = c * r / d^2

where:
c = speed of sound
r = listening distance
d = panel dimension

The calculated frequency is where the wavelength of sound is getting long enough relative to the panel dimension for the sound wave to start spreading out rather than being beamed perpendicular to the panel. So, the further you moved from the panel, the sooner the low frequencies start rolling off at 6dB/oct.
More information along with a calculator here:
Segmented Wire Stator ESL simulator (esl_seg_ui)

As an example, suppose we had a wall-sized ESL (4m x 5m) and hung it out in free space. If we compared response at listening positions of 3m and 6m distant from the ESL, the response above 100Hz would be flat and identical in level. The only difference would be that at 6m the roll off in the bass would start sooner as discussed above.
Attached Images
File Type: gif NF_3m.gif (77.2 KB, 112 views)
File Type: gif NF_6m.gif (77.2 KB, 110 views)
  Reply With Quote
Old 6th August 2013, 05:48 PM   #27
diyAudio Member
 
Join Date: Jan 2008
Location: Toronto and Delray Beach, FL
Here are the front and back pictures, as requested by Andersonix. Sorry pictures not better. CD jewel case shown for scale.

Pair of panels built around 1976 (if you are fooling with speakers and save your experiments, very good to have a house with 21 rooms). Originally powered by an oil furnace ignition transformer and two Dynaco Stereo 70 output transformers. Later, by custom HV supply and 2400 v B+ direct-drive Sanders-like amp.

These are XG8 cells, packed as closely as I could (see the back). Dayton-Wright gear is like "MIL-SPEC" construction quality among HiFi manufacturers and some other brands look like they were made in a garage. Of course, I made the crude wiring... only the cells are DW.

Each cell is 6.5 x 15.5 inches at the opening (16 cm x 40 cm). I've never measured these cells with good test equipment but they sound absolutely great to beyond my hearing range. Possibly best home audio I've ever made and possibly, ever heard, exemplifying ESL virtues like transparency and clean treble. For sure, no bass like the intact gas-filled DW XG8 or XG10 speakers (my current mid-ranges).

Ben
Attached Images
File Type: jpg Front 1976 panel.jpg (67.0 KB, 99 views)
File Type: jpg Rear 1976 panel.jpg (79.5 KB, 97 views)
__________________
Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), mixed-bass Klipschorn (28-110), and giant OB using 1960's Stephens woofer (18-110); Behringer DSP. HiFi aspirations since 1956

Last edited by bentoronto; 6th August 2013 at 05:58 PM.
  Reply With Quote
Old 13th August 2013, 09:55 AM   #28
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
Here are the drawings i was trying to find earlier,

Horn loaded electrostatic ??

jer
  Reply With Quote
Old 13th August 2013, 10:34 AM   #29
diyAudio Member
 
Join Date: Jan 2008
Location: Toronto and Delray Beach, FL
Gerald and Bolserst -

Pardon my obtuseness, I think I finally have it now. But let me begin by dropping that disinformative marketing name "AMT" and just saying "accordion-folded" or just "folded" or "pleated... like a filter."

Yes, a guy with a lot of cells can make an ESL woofer if they are folded to save room. The construction of a folded ESL is vastly more complicated than mounting plane films flat because of the number of edges to be sealed and their meandering shape.

For my Dayton-Wright cell shape, I think I could put twice the cells per inch of width. Twice more than plane but that's vastly less than the way pleated air-filters for car engines are packaged, or the imaginative patent drawings for AMTs.

Anybody ever heard such a thing? I wonder what the treble would sound like since the folded package has to be contained in a box or frame and the diaphragms are bouncing the treble off one another.....

Now a guy with a lot of cells AND a lot of wall AND a few 39-lb Dayton-Wright 1:100 transformers, might make one swell plane ESL sub-woofer (without needing to pleat them). Hmmmm.

Footnote: the bass from a pair of the gas-filled one-meter-square 8-cell Dayton-Wright ESLs is quite satisfying although far from profound. And more so, I would suppose, in the double-pair that Mike Wright advocated for theatres and that some owners use. BTW, that good bass also makes you wonder about the OB theory that predicts bass ought to be missing.

Ben
__________________
Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), mixed-bass Klipschorn (28-110), and giant OB using 1960's Stephens woofer (18-110); Behringer DSP. HiFi aspirations since 1956

Last edited by bentoronto; 13th August 2013 at 10:43 AM.
  Reply With Quote
Old 13th August 2013, 11:43 AM   #30
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
Yes, very good points!
I am sure that the highs would be lacking much so for such a system as a function of the depth of the sections (pleats).

As for as the bass is concerned I am glad to hear that it my be a feasible idea although quite very labor and material intensive.
I figure that a 4sqft. panel has about the some displacement of one 12"woofer at an acceptable SPL's.
It would take 8 panels to make up the 6db drop do to the dipole action and of course the more panels the better.

I am thinking of such a system that is small for my Desktop design, I just need to work out the construction details.

Spreading the panels out over a large area would definitely work as I am trying to think of ways to decrease the foot print (floor space).

Another thing I was thinking about was to use about 16 panels to corner load the room with.
With the panels parallel to the walls and sealed at the apex (corner).
I was thinking of a system of about 32sqft. per corner with 4 1' X 4' on each wall (8 total per corner) 8' tall.

I don't have my camera right now or else I would draw a sketch and post it for you.

I am not sure exactly if this would work but I got the crazy idea from the David Lucas Shockwave ESL sub plans so I have yet to work out the details.

I am using 2 X 10's facing into each corner right now behind my main stack of cabinets with a 250Hz passive crossover and this works very good for me.
Although they are monopole and are in phase and parallel with the corresponding stack (see picture).

I will know more too if this is going to work once I start building some larger panels.
This about to change anyhow because 3 of the 12's are now burn't.

I am leaning toward a tall dipole stack of 8's or per side at the moment.

If The ESL's in the corner idea does work then it will have a very large surface area in tucked in a small area of floor space.

Once, I get the panels made I don't want those big bulky boxes as there won't be any room for them once they are setup!!

Just a few thoughts FWIW.

jer
Attached Images
File Type: jpg my system.jpg (108.1 KB, 58 views)
File Type: jpg stack.jpg (46.0 KB, 32 views)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
MartinLogans New/Old ESL Panels tyu Planars & Exotics 4 26th February 2012 10:39 PM
New ESL panels clicking dochungwell Planars & Exotics 19 31st October 2011 01:35 AM
Acoustic Panels (lot of pics) Highef Construction Tips 6 14th September 2010 07:08 PM
JanZen ESL panels cowanrg Planars & Exotics 6 17th December 2007 06:01 PM


New To Site? Need Help?

All times are GMT. The time now is 01:27 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2