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Old 15th January 2014, 11:04 PM   #11
beanbag is offline beanbag  United States
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Quote:
Originally Posted by Calvin View Post
Imho its especially the quality and balance in the lowmids and upper bass that makes the difference between HiFi and Music.
Too low volume in that range and the system sounds anemic, with a technical note. In other words there's linear distortion.
The right volume and the system comes to life, sounding more authentic and real. If You play the panels of Hybrids alone and wo. xover You will immideately notice that larger and wider panels can put out alot of energy just in that lowmid range. This energy finds it way directly into Your guts and chest and creates a lifelike impression.
I don't think, that it is a matter of distribution spreading or an other measurable parameter, at least I don' know of a plausible explantion.
The way you say it, it sounds like just an equilization problem. But both the little low end and big high end Martin Logan speakers claim to measure fairly flat. And the low end speakers cross over at 500 Hz, and the medium end cross over only a little lower (maybe 450 hz), yet people still claim the medium end sounds better for some reason or another.

Last edited by beanbag; 15th January 2014 at 11:12 PM.
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Old 15th January 2014, 11:12 PM   #12
beanbag is offline beanbag  United States
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Quote:
Originally Posted by Bob Richards View Post
The bigger the radiating area, the more directional, which means less coloration from room reflections on many axis.
1. That seems to be Sander's approach in going back to flat panels. But if directional is what you want, why not have a smaller panel, but put some kind of sound absorbing aperture or baffles in front of the speaker to aim the sound right at your ears?

1a. And why would Martin Logan suggest you to toe out the speakers slightly instead of aiming right at your ears?

2. If less room reflections is the goal, then for a panel of the same width, a taller panel would be worse because it sprays sound at your knees, in addition to your ears. That extra sound will bounce around.
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Old 16th January 2014, 01:34 AM   #13
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I have taken the approach of building narrower panels instead of wide ones.
I like their horizontal dispersion characteristics better.

I also have started to employ electrical segmentation in my latest build as well, I just haven't gotten the needed resistors yet.

I also use a bit more D/S than most, 1.85mm is what my new panel is set and may need to be increased a little, as this will allow for more output at the lowest frequency's than your typical panel made just for the midrange and higher with a typical D/S of 1/16".

I can get really good performance down to the 150hz to 250hz range just at the edge of diaphragm\stator clipping with a D/S of 2mm (3/32") and a width of 3.25" (and a 9.75" length) or so, and it is quite loud at this point (est. about >105db at 1 meter).

To compensate for this I use a much higher Bias voltage as well.
And higher transformation ratios (1:150-250) as well are possible increasing the overall efficiency using smaller area panels.

When the panels width equals one wavelength or greater than the frequency being produced, Then the dispersion starts to transition form a figure 8 pattern in to a narrow beam and keeps getting narrower as the frequency rises.
It also produces main smaller lobes off to the sides as well.

I have no issues of getting a high output from my little panels even down to the 200hz to 300hz range, providing that the stator coatings are up to the task of with holding such high voltages and there is plenty of D/S spacing.

At the lowest Frequency's the output level is directly related to diaphragm displacement and of course the dipole cancelling effect otherwise it would have a circular horzontal dispersion because the diaphragms width is much much less than one wavelength of the frequency being produced.

Wings can help with this and in a small setup I have found that it can increase the low end output by as much as 3db.

I have had better luck with not ruining the sound quality by using reflectors directly behind the diaphragm than I have had trying to dampen the backwave with some sort of absorbing material that is close the the diaphragm.

The back pressures created from anything within about 10"-12" from the diaphragm would reduce all of the finest details in sound that ESL's are so well known for, in my earlier experiments.

Using wings will help with the low end roll off as per dipole action, But the width of the diaphragm itself will determine the horizontal dispersion effects (beaming) for the higher freqeuncys.
And the more the displacement, This helps with the low end.

It is obvious as to why ML suggests to toe out there speakers!!
Its due to the delays and refraction issues of using a curved panel.

When using a taller panel in a line source arrangement the top and bottom reflections from the ceiling and the floor give the impression of having a larger room such as mirrors would do using light waves.
Giving an extension to a virtual room, If you will.

At least that is the way I understand it from reading a lot material on the subject.

Having any space from the ends of the driver to the ceiling and floor is when the reflections are refracted differently and unequally.

FWIW

jer

Last edited by geraldfryjr; 16th January 2014 at 01:41 AM.
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Old 16th January 2014, 11:34 AM   #14
Calvin is online now Calvin  Germany
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Hi,

@Bazukaz:
Quote:
Nowhere near as boomy as a monopole sub or difficult to position like dipole sub.
... then use a dynamic dipole bass instead and position it close to the panel.
A FR ESL also puts out a dipole bass, but the dynamic dipole is way more precise due to its Q beeing lower, closer to the optimal value, the vastly increased dynamic range and more compact size.
Sensitivity problems are not solved by sheer area, but rather the SPL increases and You might eventually sitting within the nearfield. -thereby solving the suckout prob in the lower mids, but exaggerating the bass resonance.
Adding damping required a frequency specific tool, that only cuts the bass resonance but wouldnīt effect the lower mids at the same.
So it must be something other than a damping felt/mat.

@beanbag:
Quote:
... it sounds like just an equilization problem
Yes it does, but it isnīt a matter of eq alone.
In the freq-range below say 400Hz where larger/wider panels make a sonic difference neither the wide nor the thin panels beam, but radiate a widespread dipole-8.
I assume that differences in the typically higher xovered MLs are rather due to different basses as partners.

@gerald:
Quote:
Its due to the delays and refraction issues of using a curved panel.
Could You elaborate? I donīt know what You mean with "delay" and "refraction". Certainly segmentation forms delays too.
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Old 16th January 2014, 01:01 PM   #15
Bazukaz is offline Bazukaz  Lithuania
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Hi,

Quote:
Originally Posted by Calvin View Post
Hi,
... then use a dynamic dipole bass instead and position it close to the panel.
A FR ESL also puts out a dipole bass, but the dynamic dipole is way more precise due to its Q beeing lower, closer to the optimal value, the vastly increased dynamic range and more compact size.
It would be interesting to see claims of high SPL levels backed up by measurements(or simulation at least). I am curious what's the sensitivity of your dipole array at lets say 50 Hz(when equalization is not taken into account) ?
Attached is the simulation of frequency response of :

a) 8x Visaton W 200 drivers in a baffle 200x60 cm. Based on this sensitivity at 50 Hz is -15 dB or around 85 db/2.83V. heavy equalization is necessary as well as high powered amplifier. Peak SPL is limited by X,max rather than thermal power I guess.

b) Simulation of segmented ESL of the same size. As it can be seen sensitivity is more or less of similar level and even higher at lower frequencies not taking resonance into account. Perhaps it won't accept the same levels of input power like 8x dynamic drivers output can still be quite adequate, even for larger rooms.

Edit :
Max. combined displacement of a) case seems to be around 1.6 litters, compared to 1.2 litters in case of b). So there is no reason for ESL not to reach similar or even higher max. SPL, as it has more area and hence is more efficient mechanically.

Quote:
Originally Posted by Calvin View Post
Sensitivity problems are not solved by sheer area, but rather the SPL increases and You might eventually sitting within the nearfield. -thereby solving the suckout prob in the lower mids, but exaggerating the bass resonance.
Why not? Doubling area gives about 6dB more SPL and that's mostly in bass. The increase in SPL is not linear across audio range.
If the cause was displacement alone then only 3 dB were gained(as SPL = 10*log(P1/P2)). another 3 dB is gained by increased coupling to air and hence better mechanical efficiency.

Quote:
Originally Posted by Calvin View Post
Adding damping required a frequency specific tool, that only cuts the bass resonance but wouldnīt effect the lower mids at the same.
So it must be something other than a damping felt/mat.
While resonance is a significant problem with bare open ESL it can be significantly reduced. There were some measurements done by bolserst and it proves the mesh is quite effective:

Mechanical Sectioning .vs. Silicon dots for resonance control

In addition a speaker cover has a positive effect on damping as long as it's thin and light.
Regards,
Lukas.
Attached Images
File Type: png W200 dipole.PNG (42.0 KB, 134 views)
File Type: png ESL large.PNG (20.9 KB, 136 views)

Last edited by Bazukaz; 16th January 2014 at 01:09 PM. Reason: Extend
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Old 16th January 2014, 01:26 PM   #16
tyu is offline tyu  United States
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Sanders Sound Systems Dispersion Whitepaper written by Roger Sanders.


Here the go here....... i tryed to put in my frist post..........have fun
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Old 16th January 2014, 02:43 PM   #17
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I was referring to the Path length differences.
The phase differences can be greater in a curved panel than they are in a flat panel and still more so than the phase differences caused by the simple RC filter used for electrical segmentation.

Here are a few excerpt's from Frank Verwaal's paper that explains this, although it should be read in its full entirety for a complete understanding.

Elektrostatic Loudspeakers


jer
Attached Images
File Type: jpg Frank Verwaal p28.jpg (559.0 KB, 129 views)
File Type: jpg Frank Verwaal p29.jpg (820.1 KB, 126 views)
File Type: jpg Frank Verwaal p35.jpg (478.9 KB, 125 views)
File Type: jpg Frank Verwaal p42.jpg (689.2 KB, 19 views)
File Type: jpg Frank Verwaal p43.jpg (495.6 KB, 20 views)
File Type: jpg Frank Verwaal p44.jpg (743.9 KB, 20 views)
File Type: jpg Frank Verwaal p92.jpg (485.0 KB, 20 views)
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Old 16th January 2014, 02:56 PM   #18
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I think active area was 175cm x 45cm. It was a wire stator with 7 electric segmentations. The foil 1 peace but with dots of silicon ( in later smaller models i did not used this dots anymore).

Quote:
Originally Posted by Bazukaz View Post
Hi,

I know your negative bias against full range ESL but IMO there is no all round solution. I have done many experiments with my ESL system and,although it was initially designed as hybrid crossed at around 100Hz, I like the sound of full range mode much better. Nowhere near as boomy as a monopole sub or difficult to position like dipole sub.
IMO a lot depends how a full range ESL is done. Damping mesh can be added to control fundamental and active eq of few db is not difficult to implement either. It can mean difference between bad bass and good bass.
Sensitivity problems can be solved by using large area and not every one wants to damage their ears




Wow that's big. Have you used single panel or multiple small units? What was exact radiating area? Sensitivity?

Regards,
Lukas.
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Old 16th January 2014, 07:18 PM   #19
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Quote:
Originally Posted by beanbag View Post
Does anybody have any objective or technical reasons for the perceived difference in sound between a big panel and a little one?
Short version: Lower crossover point = More ESL glory, less cone woofer woofing...
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Old 16th January 2014, 07:39 PM   #20
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Quote:
Originally Posted by beanbag View Post
1. That seems to be Sander's approach in going back to flat panels. But if directional is what you want, why not have a smaller panel, but put some kind of sound absorbing aperture or baffles in front of the speaker to aim the sound right at your ears?

1a. And why would Martin Logan suggest you to toe out the speakers slightly instead of aiming right at your ears?

2. If less room reflections is the goal, then for a panel of the same width, a taller panel would be worse because it sprays sound at your knees, in addition to your ears. That extra sound will bounce around.
1a. ML suggests that as a starting point because in a typical setup, it makes the rear wave reflections come more from the center (rather than from outside the speakers), which reinforces and deepens the center image.
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